INTERNATIONAL CONFERENСE “ORGANIC NANOPHOTONICS”

(ICON-RUSSIA 2009)

SYMPOSIUM “MOLECULAR PHOTONICS”

Dedicated to Academician A.N.Terenin

SYMPOSIUM “FUNDAMENTAL PRINCIPLES OF NANOPHOTONICS”

BOOK OF ABSTRACTS

June 21-28, 2009 St. Petersburg, Russia

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Ministry of Education and Science of the Russian Federation

Russian Foundation for Basic Research

Russian Academy of Sciences

Saint-Petersburg State University

St.Petersburg State University of Information Technologies, Mechanics and Optics

Photochemistry Center RAS

Institute of Problems of Chemical Physics RAS

Consortium “Organic Nanophotonics”

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CONTENTS INTERNATIONAL CONFERENCE “ORGANIC NANOPHOTONICS” ..................... 15 ORALS ................................................................................................................ 15 LINEAR AND NONLINEAR OPTICAL PROPERTIES OF UV-INDUCED GOLD NANOPARTICLES IN POLYMERIC MATRICES Afanasiev A.V., Alexandrov A.P., Mochalova A.E., Smirnova L.A., Bityurin N.M. ................................... 15 FEMTOSECOND NANOPHOTONICS OF GOLD AND SILVER CLUSTERS PHOTODEPOSITED ON CRYSTALLINE AND AMORPHOUS MESOPOROUS FILMS OF TiO2 Aiboushev A., Astafiev A., Nadtochenko V., Sarkisov O.M. ....................................................................... 16 DISSOCIATIVE LUMINESCENT SENSOR BASED ON QUANTUM DOT/ORGANIC MOLECULE SYSTEM Baranov A.V., Maslov V.G., Orlova A.O., Toporova Yu.A., Ushakova E.V., Fedorov A.V., Cherevkov S.A. 17 SELF-AGGREGATION OF LUMINESCENT SILICA NANOPARTICLES IN AQUEOUS SOLUTIONS OF AMPHIPHILIC COMPOUNDS AND SURFACTANTS Fedorenko S.V., Mustafina A.R., Konovalova O.D., Konovalov A.I. ........................................................ 18 INCOHERENT ENERGY TRANSFER IN QUANTUM DOTS: TIME-DOMAIN LUMINESCENT SPECTROSCOPY Fedorov A.V., Baranov A.V., Kruchinin S.Yu., Ushakova E.V., Savelyeva A.V., Mukhina M.V ............... 19 THEORY OF OPTICAL NANO MANIPULATION Ishihara H., Iida T., Ajiki H. ...................................................................................................................... 20 SILICON NANOPHOTONICS: PRESENT STATUS AND PERSPECTIVES Khriachtchev L. .......................................................................................................................................... 21 NOVEL NANOCOMPOSITE MATERIALS BASED ON MESOMORPHIC GLASSES OF METAL ALKANOATES: STRUCTURES AND NONLINEAR-OPTICAL PROPERTIES Klimusheva G., Garbovskiy Y., Bugaychuk S., Tolochko A., Mirnaya T. .................................................. 22 ELECTROLUMINESCENCE OF ORGANIC MOLECULES IN BLUE-GREEN AND RED RANGES OF THE SPECTRUM Kopylova T.N., Mayer G.V., Gadirov R.M., Degtyarenko K.M., Egorova A.V., Eremina N.S., Kukhto A.V., Meshkova S.B., Topilova Z.M., Shul’gin V.F., Samsonova L.G. ............................................................... 23 LEPR STUDY OF CHARGE TRANSFER PHOTOINDUCED IN POLYMER/FULLERENE BULK HETEROJUNCTIONS Krinichnyi V.I., Yudanova E.I., Denisov N.N. ........................................................................................... 24 OPTICAL AND ELECTROPHYSICAL PROPERTIES AND APPLICATIONS OF ORGANIC AND ORGANIC-INORGANIC THIN FILM NANOSTRUCTURES Kukhta A.V. ................................................................................................................................................ 25 EFFECT OF J-AGGREGATES ON OPTOELECTRONIC PROPERTIES OF CONDUCTING POLYMERS Maltsev E.I., Lypenko D.A., Perelygina O.M., Pozin S.I., Vannikov A.V. ................................................. 26 FABRICATION OF NANO SPACE FOR CONTROL OF INCIDENT LIGHT FIELD Masuda H., Kondo T. ................................................................................................................................. 27 LASER AND ORGANIC NANOPARTICLES Masuhara H. .............................................................................................................................................. 28 QUANTITATIVE ANALYSIS OF PH AND METAL IONS SENSITIVE PHOTOCHROMIC SPIROPYRANS AND SPIROOXAZINES Micheau J.C. .............................................................................................................................................. 29

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CALIXARENE-BASED COMPLEXES AS PROMISING LUMINOPHORES FOR LUMINESCENT SILICA NANOPARTICLES Mustafina A.R., Fedorenko S.V., Konovalova O.D., Konovalov A.I. ........................................................ 30 LOW-THRESHOLD TRANSFORMATION OF FREQUENCY IN SOLID SOLUTIONS OF Zn0.6Cd0.4S WITH ADSORBED METAL-ORGANIC CLUSTERS Ovchinnikov O.V., Smirnov M.S., Leonova L.Yu., Kosjakova E.A., Latyshev A.N., Kluyev V.G. .............. 31 SUPRAMOLECULAR WATER-SOLUBLE COMPLEXES OF CAROTENOIDS Polyakov N.E., Leshina T.V., Meteleva E.S., Dushkin A.V., Konovalova T.A., Kispert L.D. .................... 32 BRANCHED AND DENDRITIC POLYARYLSILANES AS NANOSTRUCTURED LUMINOPHORES Ponomаrenko S.A., Surin N.M., Borshchev O.V., Luponosov Y.N., Shumilkina E.A., Muzafarov A.M. ... 33 THE EFFECT OF METALIC NANOPARTICLES ON THE OPTICAL CHARACTERISICS OF PORPHYNATES AND MEH-PPV SOLUTIONS Revina A.A., Tedoradze M.G., Plachev Yu.A., Bogdanova I.V. ................................................................. 34 SPECTRAL AND LUMINESCENT PROPERTIES OF SEVEREL ACRIDINE COMPOUNDS IN SOLUTIONS AND SiO2-FILMS Samsonova L.G., Selivanov N.I., Kopylova T.N., Artyukhov V.Ya., Solodova T.A. ................................... 35 OPTOELECTRONIC SENSOR SYSTEMS BASED ON THIN FILM ORGANIC ELECTRONICS Schoo H.F.M., Koetse M.M., Rensing P.A., Van Heck G.T., Meulendijks N.N.M.M., De Kok M., Kruijt P.G.M., Wieringa F.P. ............................................................................................................................... 36 FULLERENE NANOCLUSTERS AS AMPLIFIERS IN LINEAR SPECTROSCOPY AND NON-LINEAR OPTICS Sheka E.F. .................................................................................................................................................. 37 FEMTOSECOND PRIMARY CHARGE SEPARATION IN PHOTOSYSTEM I Shelaev I.V., Gostev F.E., Mamedov M., Sarkisov O.M., Nadtochenko V.A., Suvalov V.A., Semenov A.Yu. 38 ELECTRONIC SENSORS ON THE BASIS OF NANOSTRUCTURED CERIUM OXIDE FILMS Shmyryeva A.N., Borisov A.V., Maksimchuk N.V. ..................................................................................... 39 UV-LIGHT STIMULATED FORMATION OF ORGANIC NANOPARTICLES Skubnevskaya G.I., Dubtsov S.N., Dultseva G.G. ...................................................................................... 40 MATERIAL SOLUBILITY AND MISCIBILITY EFFECTS IN FULLERENE/POLYMER COMPOSITES USED AS PHOTOACTIVE MATERIALS IN ORGANIC SOLAR CELLS Troshin P.A., Khakina E.A., Susarova D.K., Hoppe H., Goryachev A.E., Peregudov A.S., Sariciftci N.S., Razumov V.F. ............................................................................................................................................. 41 PEPTIDES AGGREGATES AS SUPRAMOLECULAR NANOSYSTEMS. STRUCTURE INVESTIGATIONS BY PULSED ELECTRON-ELECTRON DOUBLE RESONANCE (PELDOR) SPECTROSCOPY Tsvetkov Yu.D., Milov A.D., Samoilova R.I. .............................................................................................. 42 NON-LINEAR OPTICAL AND PHOTONIC CRYSTALLINE CHROMOPHORE-CONTAINING POLYMERIC MATERIALS FOR OPTOELECTRONICS AND OPTOSENSORICS Yakimansky A.V., Nosova G.I., Solovskaya N.A., Smirnov N.N., Nikonorova N.A., Menshikova A.Yu., Shevchenko N.N., Evseeva T.G., Gromov S.P., Sazonov S.K., Koshkin A.V., Sazhnikov V.A., Alfimov M.V. ..................................................................................................................................................................... 43 FORMATION PRINCIPLES AND RELAXATION PROCESSES IN NANOSCALE HETEROGENEOUS COMPLEXES: MULTIPORPHYRIN ARRAYS AND CdSe/ZnS NANOCRYSTALS Zenkevich E.I., Von Borczyskowski C. ....................................................................................................... 44

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POSTERS ............................................................................................................ 45 PHOTONICS OF THE NON-CONJUGATED POLYARYLENEPHTHALIDES – NEW POLYMER CLASS FOR ELECTROLUMINESCENCE DEVICES Antipin V.A., Lachinov A.N., Nakaryakov A.S., Salazkin S.N., Kovalev A.A., Kazakov V.P ............... 45 MODELING OF NONLINEAR-OPTICAL ACTIVITY OF POLYMER ELECTRET AND RELAXATION STABILITY OF ITS QUADRATIC RESPONSE Balakina M.Yu ........................................................................................................................................... 46 CONTINUUM MODEL FOR ELECTROSTATIC ENERGY OF INTERACTION OF A DIPOLAR ION OR DIPOLAR MOLECULAR SYSTEM IMMERSED IN A SPHERICAL NANOPARTICLE Basilevsky M.V., Nikitina E.A., Grigoriev F.V., Alfimov M.V ............................................................... 47 OPTICAL CONTROL OF NANOPOROUS POLYMERS SYNTHESIS PROCESS FROM PHOTOPOLYMERIZABLE COMPOSITES Batenkin M.A., Konev A.N., Mensov S.N., Chesnokov S.A .................................................................... 48 SYNTHESIS, SELECTIVE AND PHOTOLUMINESCENT PROPERTIES OF THE DERIVATIVES OF TERPYRIDINES - EFFECTIVE MOLECULAR RECEPTORS FOR ZINC(II) ION Baulin V.E., Logacheva N.M., Safiulina A.M., Konstantinov N.Y., Tsivadze A.Y ................................. 49 PHOTOLUMINESCENT PROPERTIES OF FLUORENE-SUBSTITUTED PORPHYRINS Chernyadyev A.Yu., Plachev Yu.A., Tsivadze A.Yu ................................................................................ 50 PHOTOCHROMISM OF MEROCYANINE COMPLEXES OF DIPHENYLOXAZOL CONTAINING SPIROPYRANS WITH TRANSITION METAL CATIONS Chernyshev A.V., Metelitsa A.V., Gaeva E.B., Voloshin N.A., Minkin V.I ............................................ 51 MECHANOCHEMICAL PREPARATION OF WATER-SOLUBLE COMPLEXES OF CAROTENOIDS Evseenko V.I., Meteleva E.S., Dushkin A.V., Polyakov N.E ................................................................... 52 EFFECT OF THE CHROMOPHORES MUTUAL ORIENTATION ON NONLINEAR-OPTICAL RESPONSE OF MOLECULAR SYSTEM. QUANTUM-CHEMICAL CALCULATIONS Fominykh O.D., Balakina M.Yu ................................................................................................................ 53 INFLUENCE OF THE ORGANIC LIGHT-EMITTING DIODE STRUCTURE ON THE IR(PPY)3 ELECTROLUMINESCENCE Gadirov R.M., Degtyarenko K.M., Eremina N.S., Kopylova T.N ............................................................ 54 MODEL OF ENERGY CONVERSION EFFICIENCY FOR POLYMER PHOTOVOLTAIC CELLS Godovsky D.Yu., Inganas O ...................................................................................................................... 55 PHOTOPHYSICAL PROPERTIES OF AQUEOUS SOLUTION OF 3,3’-DIETHYLTHIACARBOCYANINE IODIDE IN THE PRESENCE OF CUCURBIT[7]URIL Golubkov D.V., Ivanov D.A., Petrov N.Kh., Alfimov M.V ...................................................................... 56 TRIPLET-TRIPLET ENERGY TRANSFER IN NANODIMENSIONAL MOLECULAR LAYERS Ibrayev N.Kh., Aimukhanov A.K., Seliverstova E.V ................................................................................ 57 SPECTROSCOPIC PROPERTIES OF LANGMUIR FILMS OF RHODAMINE DYES AND POLYAMPHOLYTIC POLYMER Ibrayev N.Kh., Smagulov Zh.K., Аlekseeva V.I., Marinina L.E., Savvina L.P ........................................ 58 NEW BLUE- AND GREEN-LIGHT-EMITTING ELECTROLUMINESCENT POLYFLUORENES WITH 7,8,10-TRIARYLFLUORINE AERIAL FRAGMENTS IN BACKBONE Keshtov M.L., Lypenko D.A., Pozin S.I., Maltsev E.I., Maltsev E.I ........................................................ 59 [C60(CN)5]-: A REMARKABLY STABLE [60]FULLERENE ANION Khakina E.A., Troshin P.A., Konarev D.V., Peregudov A.S., Soulimenkov I.V., Peregudova S.M., Lyubovskaya R.N ...................................................................................................................................... 60 SPECTRAL AND SENSING PROPERTIES OF 9-DTAA DYE IN POLYMER MATRICES Khlebunov A.A., Komarov P.V., Ionov D.S., Koshkin A.V., Sazhnikov V.A., Alfimov M.V ................ 61

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POLYSUBSTITUTED DERIVATIVES OF PALLADIUM TETRAPHENYL TETRABENZOPORPHYRIN. SYNTHESIS AND PROPERTIES Khoroshutin A.V., Chumakov D.E., Uzhinov B.M., Anisimov A.V ........................................................ 62 STRUCTURE AND NONLINEAR OPTICAL PROPERTIES OF BILAYER CELLS WITH ORGANIC AND SEMICONDUCTOR NANOFILMS COVERED BY LYOTROPIC MESOPHASE OF METAL ALKANOATES Klimusheva G., Garbovskiy Yu., Bugaychuk S., Tolochko A., Mirnaya T .............................................. 63 INVESTIGATION OF DEGRADATION PROCESSES IN ORGANIC LIGHT-EMITTING DEVICES Kondracki B.A., Usov N.N., Kruchinin A.U ............................................................................................. 64 DERIVATIVES OF DIVINYLBENZOXAZOLYLBIPHENYL: NEW ELECTROLUMINESCENT MATERIALS Kopylova T.N., Kukhto A.V., Kolesnik I.N., Kukhto I.N., Galinovski N.A., Degtyarenko K.M., Eremina N.S., Gadirov R.M ..................................................................................................................................... 65 MAGNETIC FIELD EFFECT ON THE POLYARYLENEPHTHALIDES ELECTROLUMINESCENCE Kovalev A.A., Antipin V.A., Lachinov A.N., Salazkin S.N., Kazakov V.P ............................................. 66 EXIPLEX ELECTROLUMINESCENCE SPECTRA IN THE ORGANIC LIGHT-EMITTING DIODES BASED ON SULPHANYLAMINO ZINC COMPLEXES Krasnikova S.S., Kaplunov M.G., Yakushchenko I.K .............................................................................. 67 INFLUENCE OF ETHANOL VAPORS ON SPECTRAL BEHAVIOR OF NILE RED IN ORGANIC-SILICATE MATRIX Lupikov D.I., Movchan T.G ...................................................................................................................... 68 EFFICIENT MULTILAYER ELECTROLUMINESCENT ORGANIC STRUCTURES BASED ON IRIDIUM(III) COMPLEX Lypenko D.A., Dmitriev A.V., Maltsev E.I., Vannikov A.V .................................................................... 69 DYNAMICS OF ABSORPTION AND LUMINESCENCE OF CdSe/ZnS QUANTUM DOTS IN THE PROCESS OF AGGREGATION IN HYDROPHOBIC SOLUTIONS Maslov V.G., Adrianov V.E., Orlova A.O., Baranov A.V., Fedorov A.V ................................................ 70 QUENCHING OF ELECTRONICALLY EXCITED CARBAZOLE BY A STABLE IMIDAZOLIDINE RADICAL Matveeva A.G., Stass D.V., Korolev V.V., Plyusnin V.F., Reznikov V.A ............................................... 71 OPTICAL FORMATION OF GRADED-INDEX WAVEGUIDE STRUCTURES IN PHOTOPOLYMERIZABLE COMPOSITES Mensov S.N., Polushtaytsev Yu.V ............................................................................................................. 72 NOVEL PHOTOCHROMIC SPIROPYRAN CATIONS WITH A PYRIDINIUM MOIETY IN THE ALIPHATIC SIDE CHAIN Metelitsa A.V., Besugliy S.O., Voloshin N.A., Soloveva E.V., Minkin V.I ............................................. 73 THEORETICAL STUDY OF ADSORPTION OF AN ACRIDINE DYE AND SIMPLE MOLECULES ON A SILICA SURFACE Minibaev R.F., Zhuravlev N.A., Bagaturyants A.A., Alfimov M.V ......................................................... 74 SPECTRAL BEHAVIOUR OF NILE RED IN ORGANIC-SILICATE SOL-GEL MATRIСES Movchan T.G., Lupicov D.I., Khamova T.V., Shilova O.A ...................................................................... 75 NEW PHOTOCHROMIC ASYMMETRIC BISPIROPYRAN OF THE 2,3-DIHYDRO-4-OXO-NAPHTO[2,1-E]OXAZINE SERIE Mukhanov E.L., Lukyanov B.S., Dorogan I.V., Besuglui S.O., Alexeenko Yu.S., Ryashin O.N., Tkachev V.V ............................................................................................................................................................. 76 COPOLYMERS BASED ON CYCLOPENTADITHIOPHENE FOR ORGANIC PHOTOVOLTAICS Myshkovskaya E.N., Ponomarenko S.A., Troshin P.A., Susarova S.D., Babenko S.D., Surin N.M., Muzafarov A.M .......................................................................................................................................... 77 MEAN FORCE POTENTIALS FOR ION PAIRS IN A BINARY SOLVENT MIXTURE Odinokov A.V., Basilevsky M.V., Nikitina E.A., Petrov N. Kh., Alfimov M.V ...................................... 78

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STUDY OF A POLYMER MATRIX INFLUENCE ON PHOTOCHROMISM OF SPIROPIRANES, INSERTED BY DIFFUSION FROM SOLUTIONS Optov V.A., Ait A.O., Barachevsky V.A., Berlin A.A., Sabsai O.Yu ...................................................... 79 FORMATION AND DISSOCIATION OF SEMICONDUCTOR QUANTUM DOT / DYE MOLECULE COMPLEXES Orlova A.O., Toporova Yu.A., Maslov V.G., Fedorov A.V., Baranov A.V ............................................. 80 ATOMIC FORCE MICROSCOPY STUDY OF J-AGGREGATE NANOSTRUCTURES Perelygina O.M., Prokhorov V.V., Lypenko D.A., Mal’tsev E.I., Vannikov A.V., Vannikov A.V., Vannikov A.V ............................................................................................................................................ 81 NEW EUIII AND TBIII HEXAFLUOROACETYLACETONATES WITH BIDENTATE O-DONOR LIGANDS: SYNTHESIS, STRUCTURE AND OPTICAL PROPERTIES Pleshkov D.N., Eliseeva S.V., Lyssenko K.A., Lepnev L.S., Kotova O.V., Kuzmina N.P ...................... 82 SYNTHESIS AND OPTICAL PROPERTIES OF HIGHLY LUMINESCENT CdS QUANTUM DOTS Raevskaya A.E., Grodzyuk G.Ya, Stroyuk A.L., Kuchmiy S.Ya .............................................................. 83 STARLIKE OLIGOTHIOPHENESILANES FOR PHOTOVOLTAIC APPLICATIONS Shumilkina E.A., Ponomarenko S.A., Troshin P.A., Hakina E.A., Surin N.M., Muzafarov A.M ............ 84 SYNTHESIS AND PHOTOLUMINESCENT PROPERTIES OF SOME LANTHANIDE COMPLEXES (LN = Eu3+, Gd3+, Tb3+, Lu3+) WITH ORTHO-SUBSTITUTED PHOSPHORYLPHENOLS Shuvaev S.V., Kotova O.V., Lepnev L.S., Kuzmina N.P., Baulin V.E., Tsivadze A.Yu ......................... 85 A NEW TECHNIQUE TO FABRICATE DIFFRACTIVE OPTICAL ELEMENTS ON THE BASIS OF PERMOLECULAR STRUCTURES Solovjev V.S., Volkov A.V., Rasshchepkina N.A ..................................................................................... 86 POLYMER/NANOCARBONS COMPOSITE MATERIALS FOR PHOTONICS Spitsina N.G., Lobach A.S., Kaplunov M.G .............................................................................................. 87 DESIGNING FULLERENE/POLYMER BULK HETEROJUNCTION SOLAR CELLS WITH ADVANCED ACTIVE LAYER MORPHOLOGIES Susarova D.K., Troshin P.A., Babenko S.D., Lyubovskaya R.N., Razumov V.F ..................................... 88 PHOTODISSOCIATION OF COMPLEXES OF QUANTUM DOT/ORGANIC MOLECULES EMBEDDED IN THIN POLYMER FILMS Ushakova E.V., Orlova A.O., Baranov A.V .............................................................................................. 89 SERS, SPECTROPHOTOMETRY AND AFM STUDY OF PHOTOCHROMISM OF SPIROCYCLIC COMPOUNDS ON NANOSTRUCTURED METAL FILMS Vasilyuk G.T., Maskevich S.A., German A.E., Sveklo I.F., Lukyanov B.S., Ageev L.A ........................ 90 DYNAMICS OF PHOTOPROCESSES IN NOVEL BIFUNCTIONAL SALICYLIDENEIMINOSPIRONAPHTHOXAZINES Zaichenko N.L., Levin P.P., Mardaleishvili I.R., Shiyonok A.I., Kol’tsova L.S., Os’kina O.Yu., Tatikolov A.S ............................................................................................................................................................. 91 PHOTOLUMINESCENCE KINETICS OF (ZINC)TETRAPHENYLPORPHYRIN-FULLERENE CHARGE-TRANSFER COMPLEXES Zakharova I.B., Ermolaeva G.M., Kvyatkovskii O.E., Belyakov L.V ...................................................... 92 PHOTOCHEMICAL PROCESSES IN SELF-ORGANIZED MULTIPORPHYRIN COMPLEXES Zenkevich E.I., Sagun E.I., Knyukshto V.N., Von Borczyskowski C ....................................................... 93

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SYMPOSIUM “MOLECULAR PHOTONICS” Dedicated to Academician A.N.Terenin .. 94

ORALS ................................................................................................................ 94

INTERMOLECULAR INTERACTIONS AND PHOTOPROCESSES IN MOLECULAR SYSTEMS Artyukhov V.Ya., Mayer G.V. ..................................................................................................................... 94 AN EFFECT OF THE THIRD COMPONENT ON THE LUMINESCENCE OF THE NANO-SIZED NAPHTHALENE – CYCLODEXTRIN COMPLEXES Avakayn V.G., Nazarov V.B., Vershinnikova T.G., Rudyak V.Y., Alfimov M.V. ........................................ 95 PHOTOCHROMIC NANOPARTICLES: PROPERTIES AND APPLICATIONS Barachevsky V.A. ....................................................................................................................................... 96 PHOTONIC MOLECULAR LOGIC GATES Budyka M.F. ............................................................................................................................................... 97 EFFECT OF SOLVENT POLARITY ON THE PRIMARY PHOTOPROCESSES OF CYANINE DYES Chibisov A.K. ............................................................................................................................................. 98 PHOTONICS OF HEMOGLOBIN AND MYOGLOBIN ACTIVE CENTERS Dzhagarov B.M., Lepeshkevich S.V. ........................................................................................................ 99 ACTIVITY AND SELECTIVITY OF PHOTOCATALYSTS Emeline A.V. ............................................................................................................................................. 100 TETRAPHENYLPORPHYRIN DERIVATIVES STRUCTURE AND MOLECULE SURROUNDINGS DEPENDING ON LUMINESCENT CHARACTERISTICS Ermolina E.G., Kuznetsova R.T., Gadirov R.M., Mayer G.V., Korovin Yu.V., Semenishin N.N., Rusakova N.V. .......................................................................................................................................................... 101 SPACE RADIATION IMPACT ON PREBIOTIC SYNTHESIS AND STABILITY OF BIOORGANIC MOLECULES: COMPARATIVE STUDY Gontareva N.B., Kuzicheva E.A. .............................................................................................................. 102 INTENSITIES OF IR BANDS OF SURFACE OH GROUPS OR OF THE C-H STRETCHING BANDS OF ADSORBED MOLEQULES - A NEW SPECTRAL CRITERION OF ACTIVATION OF CHEMICAL BONDS IN HETEROGENEOUS ACID CATALYSIS VIA THEIR POLARIZATION Kazansky V.B., Subbotina I.R. ................................................................................................................. 103 THE EVOLUTION OF PHOTOCHEMICALLY GENERATED RADICAL PAIRS IN GLASSY POLYMERS: RECOMBINATION FEATURES IN MACROMOLECULAR NANOREACTORS Khavina E.Yu., Ivanov V.B. ...................................................................................................................... 104 PHOTOSTIMULATED ELECTRON TRANSFER IN STRUCTURES OF MUTATIONALLY MODIFIED REACTION CENTERS FROM PHOTOSYNTHETIC BACTERIA Kotelnikov A.I., Medvedev E.S., Goryachev N.S., Barinov A.V., Stuchebrukhov A.A., Ortega J.M. ....... 105 LUMINESCENCE TECHNIQUE IN THE STUDY OF BIOLOGICAL PROPERTIES OF FULLERENE BASED HYBRID NANOSTRUCTURES Kotelnikova R.A., Mishchenko D.V., Zhokhova D.A., Barinov A.V., Rybkin A.Yu., Goryachev N.S., Bogdanov G.N., Grigoriev V.V., Romanova V.S., Kotelnikov A.I. .......................................................... 106 PHOTONICS OF SINGLET OXYGEN DIMOLS AND MONOMOLS: RESULTS OF PHOTOCHEMICAL AND LUMINESCENCE STUDIES Krasnovsky A.A. ....................................................................................................................................... 107 DFT MODELLING OF ADENINE STACKING DIMERS IN WATER Krauklis I.V., Chizhov Yu.V., Rapoport V.L. ........................................................................................... 108 MODELING OF EVOLUTIONARY PRIMITIVE ENERGY CONVERTER AND MOLECULAR DEVICES BASED ON THE ACTIVITY OF PHOTOEXCITED FLAVINS Kritsky M.S. .............................................................................................................................................. 109 ENERGY TRANSFER IN THE MOLECULAR SYSTEMS NEAR DIELECTRIC AND METAL SURFACES Kucherenko M.G., Chmereva T.M., Kislov D.A. ..................................................................................... 110

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COOPERATIVE PROCESSES OF ANTI-STOCKES LUMINESCENCE EXCITATION IN CRYSTALS WITH ADSORBED ORGANIC DYE MOLECULES Kvashnina N.V., Ovtchinnikov O.V., Latyshev A.N., Klinskikh A.F., Smirnov M.S., Suvorova T.I. ........ 111 THE ROLE OF INTRINSIC POINT DEFECTS IN SPECTRAL SELF-SENSITIZATION OF WIDE-BANDGAP OXIDE PHOTOCATALYSTS Lisachenko A.A. ....................................................................................................................................... 112 TRIPLET ENERGY TRANSFER FROM d0 ORGANOMETALLICS TO UNSATURATED HYDROCARBONS: RECENT RESULTS AND PERSPECTIVES Loukova G.V., Smirnov V.A. .................................................................................................................... 113 SENSIBILIZED ANTI-STOCKES LUMINESCENCE MECHANISM IN CRYSTALLS WITH ADSORBED METALORGANIC NANOSTRUCTURES Ovtchinnikov O.V., Suvorova T.I., Kvashnina N.V., Smirnov M.S., Latyshev A.N., Minakov D.A., Shulgin V.A. ........................................................................................................................................................... 114 LUMINESCENCE STUDY OF STABLE STACKING AGGREGATES OF NITRIC BASES OF NUCLEIC ACIDS – THE CANDIDATES FOR ROLE OF FIRST GENETIC TEMPLATES Rapoport V.L., Malkin V.M., Krauklis I.V., Maslova E.A., Goriuchko V.V. ........................................... 115 FTIR STUDY OF POROUS ICE FILMS Rudakova A.V., Marinov I.L., Tsyganenko A.A. ...................................................................................... 116 THE PRODUCTS AND MECHANISMS OF PHOTOCHEMICAL TRANSFORMATION OF O-QUINONES Shurygina M.P., Kurskii Yu.A., Druzhkov N.O., Chesnokov S.A., Abakumov G.A. ................................. 117 MESO-SUBSTITUTED POLYMETHINE DYES AS EFFICIENT SPECTRAL-FLUORESCENT PROBES FOR BIOMACROMOLECULES Tatikolov A.S., Akimkin T.M., Kashin A.S. ............................................................................................... 118 PHOTOACTIVATED TEMPLATES IN PREBIOTIC EVOLUTION PROCESSES Telegina T.A., Kolesnikov M.P., Vechtomova Yu.L., Kritsky M.S. .......................................................... 119 ADVANCES IN SPECTRAL STUDIES OF SURFACE PHENOMENA Tsyganenko A.A. ....................................................................................................................................... 120

POSTERS .......................................................................................................... 121

BACTERIORHODOPSIN-CONTAINING MULTILAYER STRUCTURES AS A MEDIUM FOR BIOMOLECULAR NEURONET DEVICES OF PHOTONICS Adamov G.E., Adamova D.A., Grebennikov E.P., Kurbangaleev V.R ................................................... 121 PROTONATION EFFECT AND SPECTRAL PROPERTIES OF PHOTOCHROMIC COMPOUNDS Ait A.O., Barachevsky V.A., Gorelik A.M., Kobeleva O.I ..................................................................... 122 SPECTRAL-FLUORESCENT STUDY OF THE INTERACTION OF THE POLYMETHINE DYE CY2 WITH DNA AND HYALURONIC ACID Akimkin T.M., Tatikolov A.S., Yarmoluk S.M ....................................................................................... 123 DFT SIMULATION OF PHOTOCATALYTIC NO REDUCTION BY СО ON Ti8O16 NANOCLUSTER Andreev A.S., Chizhov Yu.V .................................................................................................................. 124 RELAXATION OF HIGH-LYING EXITED ELECTRONIC STATES OF POLYPYRIDYL RU(II) COMPLEXES AND ITS RELATION TO SYMMETRY OF MOLECULAR STRUCTURE AND/OR ENVIRONMENT Artemyeva E.S., Litke S.V ....................................................................................................................... 125 2D-STRUCTURE EVIDENCE ON THE SURFACE OF SELF-SENSITIZED ZnO PHOTOCATALYST Basov L.L., Lisachenko A.A ................................................................................................................... 126 PHOTOPHYSICAL PROCESSES IN CATIONS OF THIACARBOCYANINE DIMERS Bazyl O.K., Artyukhov V.Ya., Mayer G.V ............................................................................................. 127 THE STRUCTURE AND PHOTOPHYSICAL PROCESSES IN SYMMETRIC POLYMETHINE DYES Bazyl O.K., Artyukhov V.Ya., Svetlichnyi V.A., Ishchenko A.A .......................................................... 128

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SHORT AND LONG-RANGE ORDER EFFECT ON RESONANCE ENERGY TRANSFER Bodunov E.N ............................................................................................................................................ 129 THE LIQUID CRYSTAL COMPOSITES CONTAINING AN IMPURITY OF FLUORESCENT CdSe NANORODS Danilov V.V., Baranov A.V., Elyashevich G.K., Orlova A.O., Utkina N.A., Khrebtov A.I .................. 130 INVESTIGATION OF SPECTRAL PROPERTIES OF ISOXAZOLE DERIVATIVES CONTAINED PHOTOCHROMIC LABEL Demina O.V., Laptev A.V., Belikov N.E., Lukin A.Yu., Zemtsov R.V., Varfolomeev S.D., Khodonov A.A. 131 HETEROGENEOUS PHOTOCATALYSIS BY ZINС PHTHALOCYANINE DERIVATIVES FOR PHENOLS OXIDATION Fedorova T.M., Petrova E.G., Derkacheva V.M., Butenin A.V., Kaliya O.L ......................................... 132 SPECTRAL-LUMINESCENT AND LASING PROPERTIES OF THE SOME SUBSTITUTED OF COUMARIN Gadirov R.M., Kopylova T.N., Samsonova L.G., Nikonov S.Yu., Logis A.G ....................................... 133 NEW RADICAL MECHANISM OF PORPHYRIN PHOTOSENSITIZED DESTRUCTION OF BIOLOGICAL MEMBRANES Gurinovich V.V., Vorobey A.V., Tsvirko M.P ........................................................................................ 134 METHOD OF NONDESTRUCTIVE READ-OUT OF INFORMATION Japaridze K., Devadze L., Maisuradze D., Sepashvili N ......................................................................... 135 INVESTIGATION OF THE PHOTOCHROMIC BEHAVIOUR OF THE RETINAL PROTEIN CHROMOPHORE MODELS Khodonov A.A., Laptev A.V., Lukin A.Yu., Belikov N.E., Zemtsov R.V., Zvezdin K.V., Shvets V.I., Barachevsky V.A., Varfolomeev S.D., Demina O.V .............................................................................. 136 INTERACTION OF CYCLOTETRAPYRROL COMPOUNDS WITH NANOPOROUS XEROGELS AND OPTICAL RADIATION OF DIFFERENT INTENSITY Kuznetsova R.T., Ermolina E.G., Telminov E.N., Mayer G.V., Arabei S.M., Pavich T.A., Solovyov K.N., Kalashnikova I.P., Ivanova S.S ................................................................................................................ 137 THE INVESTIGATION OF THE NO PHOTOADSORPTION IN CO PRESENCE ON TiO2 HOMBIFINE N BY MEANS OF KINETIC MASS-SPECTROMETRY AND THERMO-PROGRAMMED DESORPTION SPECTROSCOPY Laptenkov D.V., Mikhaylov R.V ............................................................................................................. 138 DIFFUSE REFLECTANCE SPECTROSCOPY FOR INVESTIGATION OF GAS-SURFACE INTERACTIONS ON WIDE-BANDGAP OXIDES Lisachenko A.A ....................................................................................................................................... 139 PHOTOINDUCED OXYGEN ISOTOPE EQUILIBRATION ON TiO2-X SURFACE UNDER VISIBLE LIGHT IRRADIATION Lisachenko A.A., Mikhaylov R.V., Titov V.V ........................................................................................ 140 EFFECTS OF DONOR STRUCTURE ON TRIPLET ENERGY-TRANSFER FROM AMINES TO ALKENE IN SOLUTION Loukova G.V., Lukov A.V., Smirnov V.A .............................................................................................. 141 ENERGY TRANSFER IN MOLECULES AND MOLECULAR SYSTEMS Mayer G.V., Artyukhov V.Ya ................................................................................................................. 142 PROBE PHOSPHORESCENCE AND TRIPLET-TRIPLET ENERGY TRANSFER IN THE STUDY OF CONFORMATIONAL CHANGES IN THE PROTEINS Melnikov A.G., Kochubey V.I., Pravdin A.B., Naumova E.V., Dyachuk O.A., Melnikov G.V ............ 143 COMBINED KINETIC, UV-VIS, FTIR AND TPD STUDY OF THE PHOTOCATALYTIC NO REDUCTION BY CO ON TiO2 Mikhaylov R.V., Lisachenko A.A., Shelimov B.N., Martra G., Coluccia S., Che M ............................. 144 MATHEMATICAL SIMULATION OF STRATEGY FOR THE CONTROL OF EXCITED-STATE INTRAMOLECULAR REVERSIBLE PROTON TRANSFER IN THE MULTIPARAMETRIC FLUORESCENCE PROBES Morozov V.A ........................................................................................................................................... 145

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PREPARATION OF MAGNESIUM PHTHALOCYANINE NANOCRYSTALS Nadolinskaya S.S., Meshkov A.M., Maslov V.G., Korotkov V.I ........................................................... 146 PHOTOCHEMICAL TRANSFORMATIONS OF CHALCONE PODANDS IN THE CRYSTALS AND SOLUTIONS Ovchinnikova I.G., Fedorova O.V., Druzhinin A.V., Rusinov G.L., Charushin V.N ............................. 147 TWO-PHOTON PHOTOPROCESSES IN MOLECULAR SYSTEMS Plotnikov V.G., Smirnov V.A., Alfimov M.V ......................................................................................... 148 FTIR STUDY OF METHANE INTERACTION WITH OXIDE ADSORBENTS Poretskiy M.S., Tsyganenko A.A ............................................................................................................ 149 LUMINESCENT INVESTIGATION OF ACRIDINE HOMO-CONJUGATED COMPLEX Rozhkova J.A., Gurinov A.A., Lesnichin S.B., Shenderovich I.G., Maslov V.G., Korotkov V.I ........... 150 PROTONATED NITROGEN-CONTAINING AROMATIC MOLECULES. SPECTROSCOPIC INVESTIGATION Rozhkova J.A., Gurinov A.A., Lesnichin S.B., Shenderovich I.G., Maslov V.G., Korotkov V.I ........... 151 ETHYLENE PHOTOPOLYMERIZATION ON ZEOLITE NA–ETS-10: IR SPECTROSCOPIC STUDY Rudakova A.V., Lobo R.F., Ryabchuk V.K., Bulanin K.M .................................................................... 152 PHOTO-OZONOLYSIS OF CHLORINATED ETHENES AND HYDROGEN CYANIDE ON WATER ICE FILMS Rudakova A.V., Marinov I.L., Tsyganenko A.A ..................................................................................... 153 THE EFFICIENCY OF UV STIMULATED FORMATION OF ACTIVE CENTERS AT THE SURFACE OF MICRO- AND NANO-DISPERSED ZRO2 PHOTOCATALYSTS Ryabchuk V.K., Emeline A.V., Kataeva G.V., Kuzmin G.N., Sheremetyeva N.V ................................ 154 DECAY TIME OF ACTIVE SURFACE CENTERS ON WIDE BAND GAP METAL OXIDES Ryabchuk V.K., Emeline A.V., Kataeva G.V., Sheremetyeva N.V ........................................................ 155 STRUCTURE AND PHYSICO-CHEMICAL PROPERTIES OF PHOTOACTIVE SUPRAMOLECULAR SYSTEMS BASED ON CROWN-CONTAINING OLIGOTHIOPHENE DERIVATIVES Selector S.L., Arslanov V.V., Fedorova O.A., Lukovskaya E.V., Bobyleva A.V., Tarasova N.A., Fedorov Y.V., Raitman O.A., Anisimov A.V., Anisimov A.V ............................................................................. 156 DETERMINATION OF MAGNETIC-DIPOLE TRANSITION 5D0 – 7F1 PURITY IN EUROPIUM CHLORIDE LUMINESCENCE IN SOLUTION BY ENERGY TRANSFER TO DYES Shakhverdov T.A ..................................................................................................................................... 157 COMPARATIVE STUDY OF SPECTRAL PROPERTIES OF CROSS-CONJUGATED BISAMINOKETONES AND DINITRILES Shvedova L.A., Tatikolov A.S., Krasnaya Zh.A ..................................................................................... 158 DECAY KINETICS OF TRIPLET STATES AND RADICALS OF FLAVINS IN THE BOVINE LENS STUDIED BY LASER FLASH PHOTOLYSIS Tatikolov A.S., Levin P.P., Sultimova N.B., Panova I.G ........................................................................ 159 FLUORESCENCE RESONANCE ENERGY TRANSFER AND COMPLEX FORMATION BETWEEN CYANINE DYES AND DNA Tatikolov A.S., Pronkin P.G .................................................................................................................... 160 REACTIONS OF PHOTOINDUCED AND THERMAL RECOORDINATION IN OPTICAL MOLECULAR SENSORS Ushakov E.N., Dmitrieva S.N., Vedernikov A.I., Kuz’mina L.G., Freidzon A.Ya., Alfimov M.V., Gromov S.P .............................................................................................................................................. 161 INFLUENCE OF THE SOLVENT ON THE RADIUS OF ELECTRON-EXCHANGE INTERACTIONS OF d0 METAL COMPLEXES WITH CYCLOPENTADIENE Vasiliev V.P., Loukova G.V., Smirnov V.A ............................................................................................ 162 FTIR EVIDENCE FOR LEWIS ACIDITY INDUCED BY ADSORPTION Voronina K.V., Tsyganenko A.A ............................................................................................................ 163

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SYMPOSIUM “FUNDAMENTAL PRINCIPLES OF NANOPHOTONICS” ............. 164

ORALS .............................................................................................................. 164

OBTAINING, PROPERTIES AND PERSPECTIVES OF COLLOIDAL QUANTUM DOTS Brichkin S.B., Spirin M.G., Nikolenko D.Yu., Gak V.Yu., Razumov V.F. ................................................ 164 SEMICONDUCTOR QUANTUM DOT MOLECULE PHOTOLUMINESCENCE MEDIATED BY INCOHERENT REVERSIBLE ENERGY TRANSFER Fedorov A.V., Baranov A.V., Kruchinin S.Yu., Savelyeva A.V., Mukhina M.V. ...................................... 165 MOLECULAR DESIGN OF LIGHT-SENSITIVE NANOSIZED SYSTEMS BASED ON UNSATURATED AND MACROCYCLIC COMPOUNDS Gromov S.P., Ushakov E.N., Vedernikov A.I., Kuzmina L.G., Alfimov M.V. .......................................... 166 AOT/WATER/HEXANE REVERSE MICELLES AS “MICELLAR SIEVES” FOR CYANINE DYE J-AGGREGATES Ivanchikhina A.V., Nikolenko L.M. .......................................................................................................... 167 DELAYED FLUORESCENCE ANNIHILATION KINETICS CHANGE BY RECONSTRUCTION OF POLYMERIC CHAIN STRUCTURE IN SOLID SORBENT CAVITIES AND ON NANOPARTICLE SURFACES Kucherenko M.G., Izmodenova S.V., Kruchinin N.Y. .............................................................................. 168 THE FEATURES OF THE RECOMBINATION PROCESSES INTO THE PYROLYTIC CdS FILMS Maiorova T.L., Klyuev V.G., Pham Thi Hai M., Bikovskaya V.S. ........................................................... 169 LUMINOPHORE-CONTAINING MONODISPERSE POLYMERIC NANOPARTICLES: DESIGN, SELF-ASSEMBLING, AND APPLICATION FOR CHEMISENSORICS Menshikova A.Yu., Shevchenko N.N., Evseeva T.G., Yakimansky A.V., Sazhnikov V.A., Koshkin A.V., Alfimov M.V. ............................................................................................................................................ 170 MOLECULAR DYNAMICS SIMULATIONS OF AN AOT REVERSE MICELLES SELF-ASSEMBLY Nevidimov A.V. ......................................................................................................................................... 171 SUPRAMOLECULAR ENSEMBES OF Ru(II) PHTHALOCYANINATE, NONLINEAR OPTICAL AND PHOTOREFRACTIVE PROPERTIES Pereshivko L.Ya., Vannikov A.V., Grishina A.D., Zolotarevsky V.I., Gorbunova Yu.G., Enakieva Yu.Yu., Krivenko T.V., Savelyev V.V., Tsivadze A.Yu. .......................................................................................... 172 POLARISATION ANISOTROPY OF SINGLE-CRYSTAL OPAL FILMS Plekhanov A.I., Chubakov V.P., Chubakov P.A. ...................................................................................... 173 LASING IN PHOTONIC CRYSTAL OPAL FILMS AND HETEROSTRUCTURES Plekhanov A.I., Kuchyanov A.S. .............................................................................................................. 174 POLARIZATION AND ORIENTATION ANISOTROPY OF RESONANT OPTICAL PROPERTIES IN POLYMER 3D PHOTONIC CRYSTALS Selkin A.V., Fedotov V.G., Ukleev T.A., Menshikova A.Yu., Shevchenko N.N. ....................................... 175 NANOPHOTONICS OF FULLERENE SOLUTIONS Sheka E.F., Razbirin B.S. ......................................................................................................................... 176 NANOPHOTONICS IN PRINTING AND PACKAGING. DIGITAL AND ANALOGUES IMAGES TREATMENT AND PRODUCING Sherstiuk V., Molodid S. ........................................................................................................................... 177 PHOTOPHYSICAL AND PHOTOCHEMICAL EFFECTS IN ASSEMBLIES OF NANOPARTICLES IMMOBILIZED ON METAL OR DIELECTRIC SUBSTRATES AND MOLECULAR TEMPLATES Strekal N.D., Maskevich S.A. ................................................................................................................... 178 SEMICONDUCTOR PHOTOCATALYSIS ON THE NANOSCALE: STATE-OF-THE-ART AND PERSPECTIVES Stroyuk A.L., Kuchmiy S.Ya., Kryukov A.I., Pokhodenko V.D. ................................................................ 179

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COFLUORESCENCE OF DYES IN NANOSTRUCTURES OF METAL ION COMPLEXES WITH DIKETONES Sveshnikova E.B., Ermolaev V.L., Dudar S.S. ......................................................................................... 180 NANOSIZE STRUCTURES IN POLYMER BASED SOLAR CELLS Tameev A.R., Vannikov A.V. .................................................................................................................... 181 SPATIAL DISPERSION AND LOCAL FIELD EFFECTS FOR SEMI-INFINITE MEDIA WITH EMBEDDED NANOPARTICLES Tishchenko A.A., Ryazanov M.I., Strikhanov M.N. .................................................................................. 182 ORDERED STRUCTURES ON THE BASIS OF SELF-ASSEMBLY OF CdSe AND Au PARTICLES Zaporohzets M.A., Nikolaichik V.I., Volkov V.V., Baranov D.A., Dembo К.А., Syl’yanov S.N., Zhigalina O.M., Gubin S.P., Avilov A.S., Khodos I.I. .............................................................................................. 183 OPTICAL PROPERTIES OF NANO-STRUCTURED POLYMER LIQUID CRYSTAL COMPOSITES Zharkova G.M., Petrov A.P., Khachaturyan V.M. ................................................................................... 184 POSTERS .......................................................................................................... 185 DIFFERENTIAL PARAMETERS OF ORGANIC PHOTOELEMENT WITH BULK HETEROJUNCTION Babenko S.D., Moskvin Yu.L., Troshin P.A., Balakai A.A. ................................................................... 185 A COMPARISON OF THE PHOTOPHYSICAL PROPERTIES OF CADMIUM CHALCOGENIDE NANOPARTICLES SYNTHESIZED BY VARIOUS METHODS Gak V.Yu., Nikolenko D.Yu., Brichkin S.B., Razumov V.F., Zaporozhets M.A ................................... 186 INVESTIGATION ON THE POSSIBILITY OF COVERING CYANINE DYE J-AGGREGATES WITH SILICA SHELLS Ivanchikhina A.V ..................................................................................................................................... 187 THE LUMINESCENCE OF POLYMER COMPOSITE MATERIALS WITH CdS NANOPARTICLES Kochubey V.I., Konyukhova Ju.G., Zabenkov I.V .................................................................................. 188 PHOTOELECTRIC NONLINEAR OPTICAL AND PHOTOREFRACTIVE PROPERTIES OF COMPOSITES FROM POLYVINYLCARBAZOLE AND SINGLE-WALLED CARBON NANOTUBES Krivenko T.V., Pereshivko L.Ya., Grishina A.D., Savelyev V.V., Rychwalski R.W., Vannikov A.V .. 189 ZIRCONIA NANOPARTICLES AS NEW MODEL MATERIAL FOR NANOPHOTONICS: EFFECTS OF SELF-ORGANIZATION Lybenets V.A., Gorban O.A., Lyubchanskii I.L., Danilenko I.A., Konstantinova T.E ........................... 190 LIGHT EMITTING AND OPTICAL PROPERTIES OF SILICON-RICH SILICON NITRIDE AND SILICON-RICH SILICON OXIDE FILMS Nikitin T., Khriachtchev L., Novikov S., Rasanen M ............................................................................. 191 CLUSTERING OF CADMIUM TELLURIDE QUANTUM DOTS IN A WATER SOLUTION IN THE PRESENCE OF METAL IONS: THE ABSORPTION AND LUMINESCENT ANALYSIS Orlova A.O., Savelyeva A.V., Mukhina M.V., Maslov V.G., Baranov A.V., Fedorov A.V .................. 192 SILICA NANOPARTICLES MODIFIED BY PYRYLOCYANINE DYE WITH EFFECTIVE LUMINESCENT RESPONSE Orlova N.A., Kargapolova I.Yu., Shelkovnikov V.V., Plekhanov A.I .................................................... 193 COMPARISON STUDY OF THE NONLINEAR OPTICAL PROPERTIES OF MOLECULAR J- AND H- AGGREGATES IN THIN SOLID FILMS Plekhanov A.I., Gorkovenko A.I., Orlova N.A., Simanchuk A.E., Shelkovnikov V.V .......................... 194 LARGE ANGULAR DISPERSION EXPERIENCED BY A LIGHT BEAM IN PASSING THROUGH THE BOUNDARY OF A GLASS SUBSTRATE-PHOTON CRYSTAL Plekhanov A.I., Zabolotskii A.A., Kuchyanov A.S ................................................................................. 195

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PHOTONIC BAND GAP IN PHOTONIC CRYSTAL FORMED BY THE HOLOGRAM Shcheulin A.S., Angervaks A.E., Kupchikov A.K., Ryskin A.I .............................................................. 196 STRUCTURAL ASPECT OF NANOPHOTONICS OF FULLERENE SOLUTIONS Sheka E.F., Razbirin B.S., Starukhin A.N., Nelson D.K., Degunov M.Yu., Troshin P.A., Lyubovskaya R.N., Fazleeva V.P., Gubskaya V.P., Nuretdinov I.A ............................................................................. 197 MONODISPERSE POLYMERIC NANOPARTICLES MODIFIED WITH CYCLODEXTRINS AND DYES Shevchenko N.N., Menshikova A.Yu., Noskova I.V., Shabsels B.M., Yakimansky A.V ...................... 198 RELATIONSHIP BETWEEN WATER VAPOR PRESSURE OF REVERSE MICELLAR SYSTEM AND REVERSE MICELLES SIZE DISTRIBUTION Tovstun S.A., Razumov V.F .................................................................................................................... 199 THE STUDY OF ENDOTAXIAL NANOSTRUCTURIZATION OF POLY(3-HEXYLTHIOPHENE)/FULLERENE COMPOSITE BY LIGHT-INDUCED ESR SPECTROSCOPY Yudanova E.I., Krinichnyi V.I ................................................................................................................. 200 ELECTROOPTICAL PROPERTIES OF POLARIZATION HOLOGRAPHY GRATINGS IN POLYMER DISPERSED LIQUID CRYSTALS Zharkova G.M., Streltsov S.A., Petrov A.P., Khachaturyan V.M ........................................................... 201 INDEX ....................................................................................................................................... 202

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INTERNATIONAL CONFERENCE “ORGANIC NANOPHOTONICS”

ORALS

LINEAR AND NONLINEAR OPTICAL PROPERTIES OF UV-INDUC ED

GOLD NANOPARTICLES IN POLYMERIC MATRICES

A.V. Afanasiev1, A.P. Alexandrov1, A.E. Mochalova2, L.A. Smirnova2, N.M. Bityurin1

1 - IAP RAS, 330 Department, Nizhniy Novgorod, Russia

2 - NNSU, Nizhniy Novgorod, Russia ava@ufp.appl.sci-nnov.ru

Over the last decade, there has been a growing scientific interest in searching novel nanostructured materials all over the world. We report investigation of linear and nonlinear optical properties of UV-induced gold nanoparticles in polymeric matrices. Unlike common methods of structured materials preparation with using incorporating steady nanosized objects into polymer matrix, we represent new materials, where structured domains are formed by irradiation initially nonstructured material in specific spectral band (UV). This fact opens the opportunity of varying shape of growing structures, setting necessary properties in obtained regions with new optical properties. Moreover, it could be done locally with focused laser beam. Our experimental setup based on Er-doped fiber laser generating 100 fs pulses on wavelength 1570 nm. Highly sensitive method based on spectrally resolved two-beam coupling technique was used for detection of optical nonlinearity in thin polymeric films in IR spectral range. The main idea of this method of measurements is to mix two beams with high and low intensity in focal area. Intensive femtosecond pulse leads to refractive index addition. Weak pulse gets additional phase shift, so its spectrum changes. Thus, spectral analysis allows getting information about nonlinear optical properties of studied media. The nonlinearity activation time could be measured with using time delay between pump and probe femtosecond laser pulses. High figures of nonlinear refractive index and two-photon absorption coefficient were obtained in studied materials. Further studies will optimize the composition and conditions of preparation for higher optical nonlinearities. Linear refractive index changes were demonstrated while phase diffraction gratings were studied. Good efficiency of diffraction transformation was shown with visible and IR laser radiation. More complicated structures were recorded in modified media. These structures lead to multiplexing of laser beam. High damage threshold of studied materials, precise localization of modified areas, low cost and simple technique of preparation, high stability and longevity are additional advantages among other advanced non-linear optical materials. Obtained 3D-structures deep inside of samples are safe of surface damage. Materials have low optical losses in wide spectral range, so they could be widely adopted in real devices.

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FEMTOSECOND NANOPHOTONICS OF GOLD AND SILVER CLUSTERS PHOTODEPOSITED ON CRYSTALLINE AND AMORPHOUS MESOPOROUS FILMS OF TiO 2

A. Aiboushev, A. Astafiev, V. Nadtochenko, O.M. Sarkisov

N.N. Senenov Institute of Chemical Physics RAS, Moscow, Russia

aiboosh@gmail.com

Mesoporous films, composed from TiO2 nanoparticles can be used as a photocatalyst for light to chemical energy conversion. Metal nanoparticles photodeposited on TiO2 surface can improve catalytic properties of TiO2. The effects of electromagnetic field enhancement by metallic nanoparticles could be the most important reason for dramatic increase of Raman scattering cross section or for enhancement in luminescence spectroscopy. Luminescence of gold and silver nanoparticles on titan dioxide nanoparticles of the mesoporous film is studied for the case of crystalline and amorphous forms of TiO2. Ag and Au metal nanoparticles were prepared on the porous TiO2 film by photodeposition technique. Such a system has three main characteristic features: first, TiO2 nanoparticle size is about 25nm; second, the average distance between metal nanoparticles is of order of several nm; third, size of metal nanoparticles is less than 10nm. Luminescence was registered under the two-photon excitation by femtosecond laser pulses of Ti:sapphire laser at 800nm. It occurs that Ag/TiO2 and Au/TiO2 mesoporous films have high concentration of bright luminescence points (hot spots) which reveal stability to degradation under long illumination. Luminescence of the mesoporous film in range from 400 to ~750nm (at 800nm pumping) means two-photon absorption in mesoporous film. Mesoporous film has quite nonuniform hot spots distribution. Therefore there are some specific nanoparticles configurations in the film which the most effectively enhance electromagnetic field. Estimation of enhancement of hot spot luminescence in experiment is of order of 104. On the other hand, the effect of two-photon absorption and further luminescence is proportional to

4E , where E is amplitude of electromagnetic field at wavelength of excitation. Therefore hot

spot field enhancement at wavelength of excitation (800nm) should be 44 10 10≈ = . Size, shape and geometry effects of Ag and Au nanoparticles studied by FDTD computer simulation. Local plasmon resonance (LPR) position was found for dimmer , trimer and chain of metal nanoparticles. LPR positions are in range 360-500nm and 500-650nm for silver and gold nanoparticles respectively. TiO2 mesoporous film leads to several time higher absorption at 800nm (excitation wavelength). Local field enhancement of Ag/TiO2 and Au/TiO2 composites was ~10 (coincides with estimation from experiment). Dependence of luminescence intensity on excitation laser pulse polarization studied experimentally for “hot spots” of mesoporous film. It occurred each “hot spot” luminescence has different dependence on excitation laser pulse polarization which in accordance with model of two-close nanoparticle. Enhancement of Raman scattering of molecules deposited on Ag/TiO2 and Au/TiO2 mesoporous films was demonstrated for the case of Rhodamine B. Properties of Ag/TiO2 and Au/TiO2 mesoporous films show its promising usage for single molecule spectroscopy and biological objects visualization with high sensitivity.

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DISSOCIATIVE LUMINESCENT SENSOR BASED ON QUANTUM DOT / ORGANIC MOLECULE SYSTEM

A.V. Baranov, V.G. Maslov, A.O. Orlova, Yu.A. Toporova,

E.V. Ushakova, A.V. Fedorov, S.A. Cherevkov

St.Petersburg State University of Information Technologies, Mechanics and Optics, Russia a_v_baranov@yahoo.com

Luminescent sensors comprising complex of semiconductor nanocrystal (quantum dot, QD) and molecule are of great interest at present. Particularly they can be used for detection of different metal ions in water solution. These sensors demonstrate changes of QD luminescence intensity depending on concentration of analyte in probe. Usually, QD luminescence in QD/molecule complexes is quenched by fluorescence resonant energy transfer (FRET) from QD to molecule. In one type of sensors absorption spectrum of molecule is changed in presence of analyte following reduction of overlapping integral and increasing of QD luminescence intensity [1]. In other case increase of QD luminescence intensity results from the complex dissociation in presence of the analyte [2]. We report results of study of dissociative luminescent sensor based on complex comprising luminescent hydrophobic core/shell CdSe/ZnS QDs and 1-(2-pirydilazo)-2-naphtol (PAN) molecules. PNG is known as an indicator of Co and Ni ions [3]. By means of absorption-luminescent analysis it was shown that in organic solutions QD and PAN form complex where PAN is coupled with QD shell Zn ion by coordination bond. At QD size corresponding to optimal value of the overlapping integral the QD luminescence is practically quenched. It was found that PAN in some organic solutions or in thin polymer films is able to extract Co and Ni ions from neighbouring water solution and forms complexes with them. It was also shown the same takes place in case of QD/PAN complexes in organic solutions or thin polymer film. We found that presence of Co or Ni ions in organic solution or film results in dissociation of the QD/PAN complexes and formation stable complexes PAN with these metal ions. Importantly dissociation of QD/PAN complexes is followed by appearance of QD luminescence which intensity is proportional to concentration of the metal ions in analyzed water solution that can be used in analytical purposes. We also discovered that stability of the QD/PAN complexes depends on value of water solution pH and showed that this sensor can be used for pH measurements in 3-5 range. Finally, since application of the luminescence sensors presupposes optical excitation of the luminescence, we present results of study of QD/PAN complex photodissociation in polymer films. 1. Brogan L., Lui W., “Semiconductor nanocrystal complexes and methods of detecting

molecular interactions using same”, US patent 2007003948, 2007 2. Mogul R., “Luminescent nanosensor”, WO patent 2006083269, 2006. 3. D. Betteridge at all, Anal. Chem., vol. 35, No 6, pp. 729-733 (1963).

18

SELF-AGGREGATION OF LUMINESCENT SILICA NANOPARTICLE S IN AQUEOUS SOLUTIONS OF AMPHIPHILIC COMPOUNDS

AND SURFACTANTS

S.V. Fedorenko1, A.R. Mustafina1, O.D. Konovalova2, A.I. Konovalov1

1 - A.E. Arbuzov Institute of Organic and Physical Chemistry RAS, Kazan, Russia 2 - A.M. Butlerov Chemistry Institute, Kazan State University, Russia

svetlana.fedorenko@yahoo.com

Self-aggregation of nanoparticles is a key problem in nanochemistry. The unguided agglutination restricts the use of nanoparticles as biomarkers and biosensors, while the directed self-aggregation sometimes is of great interest as a prerequisite for 3D nanostructured architechtures. The present report introduces our recent studies of self-aggregation processes taking place in aqueous dispersions of luminescent silica nanoparticles at various concentrations of amphiphilic salts and surfactants. The silica coated Tb(III)-p-sulfonatothiacalix[4]arene (Tb(III)-TCAS) nanoparticles (40±5 nm) both unmodified and modified by amino- and carboxy anchoring groups were used as main building blocks. The analysis of conductometric, electrophoretic and dynamic light scattering data of the abovementioned nanoparticles at the varied concentrations of

amphiphilic counter ions reveal the key factors driving the nanoparticles self-aggregation. The presence of the ionised groups on the particle surface is the main, but not the only way of the nanoparticles stabilization, which restricts them from the agglutination. Covering of the nanoparticles by ionic and non-ionic surfactants double layer is another way to prevent their unguided self-aggregation in diluted solutions of surfactants. The further increase of surfactants concentrations prompts the self-aggregation of nanoparticles. These aggreagates can be separated from the aqueous solutions by temperature induced

phase separation procedure. The advantages and drawbacks of the surfactant induced self-aggregation of nanoparticles for the development of 3D colloid architechtures is discussed. Acknowledgements We thank RFBR (grant N 07-03-00282) and BRHE REC 007 for financial support. 1. A.R. Mustafina, S.V. Fedorenko, O.D. Konovalova, A. Yu. Menshikova, N.N. Shevchenko,

S.E. Soloveva, A.I. Konovalov, I.S. Antipin, Langmuir, 25 ( 2009) 3146-3151.

silica matrix

Tb(III)-TCAS

layer or bi-layer of surfactant

19

INCOHERENT ENERGY TRANSFER IN QUANTUM DOTS: TIME-DOMAIN LUMINESCENT SPECTROSCOPY

A.V. Fedorov, A.V. Baranov, S.Yu. Kruchinin, E.V. Ushakova,

A.V. Savelyeva, M.V. Mukhina

St.Petersburg State University of Information Technologies, Mechanics and Optics State University of Information Technologies, Mechanics and Optics, Russia

a_v_fedorov@inbox.ru

The investigation of nonradiative energy transfer between pairs of spatially separated quantum dots (QDs) is one of the most important problems in modern solid-state physics. In recent years, this phenomenon in QD systems has been extensively studied both experimentally and theoretically. This interest is stimulated by predicted future technological applications such as luminescent markers and sensors [1], low-threshold lasers [2], cellular automata [3], and quantum computers [4]. In addition, an ensemble of QDs is a good model for the detailed investigation of the basic physics of nonradiative energy-transfer phenomena. Because of the quantum size effect, one can generate a resonance condition between arbitrary electronic states of the QD donor and QD acceptor by choosing quantum dots of a suitable size and shape. This allows the investigation of the dependence of energy-transfer efficiency on the properties of the electronic states involved in this process. In present work based on our previous results [5] the theory of photoluminescence in time-domain for semiconductor quantum dot molecule with the incoherent energy transfer is developed. Using a two-band model and under the assumption that interaction between electrons of the QD-donor of energy and QD-acceptor of energy is described by a screened Coulomb potential, we calculate kinetics of the photoluminescence signals at pulse excitation. This approach allows us to adequately consider the specific cases of short interdot distances and dipole-forbidden transitions in the acceptor. We restrict our consideration to a case when the energy transfer rate DAγ between QDs is well below the dephasing rate DAΓ for this transition, i.e. we study the incoherent energy transfer. Both the reversible and irreversible regimes of energy transfer have been investigated. First of them takes place if the intraband energy relaxation rate Aγ for QD-acceptor is equal in order of value or less than DAγ . In this case some portion of the energy will come back from the QD-acceptor to the QD-donor. Second regime is realized if DAA γγ >> . Our results are of important for a better insight into physical processes in one-, two-, and three-dimensional structures with enough close-packed arrangement of QDs, e.g. in the quantum dot molecules, chains, rings, two- and three-dimensional arrays as well as the dendrites based on QDs. 1. X. Michalet, F. F. Pinaud, L. A. Bentolila et al., Science 307, 538 (2005). 2. S. Noda, Science 314, 260 (2006). 3. A. Imre, G. Csaba, L. Ji et al., Science 311, 205 (2006). 4. S. Sangu, K. Kobayashi, A. Shojiguchi et al., Phys. Rev. B 69, 115334 (2004). 5. S.Yu. Kruchinin, A.V. Fedorov, A. V. Baranov et al., Phys. Rev. B 78, 125311 (2008).

20

THEORY OF OPTICAL NANO MANIPULATION

H. Ishihara1, T. Iida2, H. Ajiki 3

1 - Osaka Prefecture University, Department of Physics and Electronics, Sakai, Japan 2 - Osaka Prefecture University, Research Institutes for the Twenty-First Century, Sakai, Japan

3 - Osaka University, Graduate School of Engineering, Suita, Japan ishi@pe.osakafu-u.ac.jp

In spite of recent progress in optical manipulation techniques of small objects such as laser tweezers and laser cooling, the manipulation of nanoscale objects by the radiation force is still challenging in nanotechnologies. The light-scattering cross section of nano particles is usually too small to exert enough force to trap or move them. Recently, we have theoretically revealed that an electronically resonant optical response causes a radiation force strong enough to manipulate nanoscale objects [1], which opens the way to a new type of optical manipulation linked with quantum-mechanical properties of nanoscale objects. For example, it would enable us to perform size-selective manipulation of nanoparticles by using the mechanism that the resonant optical response of quantum-mechanically confined electronic states is extremely sensitive to the particle size. In the experiment demonstrated in the superfluid He, a preliminary result of size-selective manipulation of quantum dots has been obtained [2]. In this talk, we introduce our theoretical proposal on nano optical manipulation and related experimental results described above. We also discuss our latest theoretical results, such as those on the manipulation of nanoscale objects by designed light fields [3], size selective manipulation of carbon nanotubes [4], and the inter-particle radiation-induced force that would be useful for the manipulation of collective motion of nanoscale objects [5][6]. [1] T. Iida and H. Ishihara: Phys. Rev. Lett. 90, 057403 (2003), Also see Phys. Rev. Focus 11, Story 6, 11 Feb. (2003) [2] K. Inaba, K. Imaizumi, K. Katayama, M. Ichimiya, M. Ashida, T. Iida, H. Ishihara, and T. Itoh: phys. stat. solid. (b) 243, 3829 (2006). [3] T. Iida, T. Yoshimizu, and H. Ishihara:phys. stat. sol. (c)6, 69 (2009) [4] H. Ajiki, T. Ishikawa, T. Iida, and H. Ishihara phys. stat. sol. (c)6, 65 (2009) [5] T. Iida and H. Ishihara: Phys. Rev. Lett. 97, 117402 (2006) [6] T. Iida and H. Ishihara: Phys. Rev. B77, 245319 (2008) Also see Phys. Rev. Focus 21, Story 21, 25 June (2008)

21

SILICON NANOPHOTONICS: PRESENT STATUS AND PERSPECTIVES

L. Khriachtchev

Laboratory of Physical Chemistry, University of Helsinki, Finland leonid.khriachtchev@helsinki.fi

Photonics is a leading technology of this century, and developing this area based on silicon technology promises revolutionary progress in optoelectronics. Integration of all optical functions into silicon is a strong challenge, and Si nanocrystals (Si-nc) open a remarkable perspective here.1 We present a series of experimental data on optical and structural characterization of Si-nc in silica matrix. Raman spectroscopy characterizes the structure of Si-nc. Spectral filtering of photoluminescence observed in these absorbing films allows measuring their optical properties.2

The 1.5-eV photoluminescence of these samples shows systematic correlations with the optical and structural properties and chemical composition estimated by X-ray photoelectron spectroscopy. Based on the obtained data, the light-emission mechanisms are discussed.3

Laser radiation can crystallize amorphous Si nanostructures embedded in silica, which also changes the optical properties.4,5 Recently we have found that the laser effect on silicon nanostructures in silica films can be done in small areas of submicron sizes, and this optical change is detectable by camera photographs and by Raman scattering and transmission measurements.6 The microscopic structure and hence the optical response are stable at very high temperatures as it is demonstrated by prolonged furnace annealing at 1200 °C. The developed methods provide optical data with high density and a very long retention times suitable for extreme temperature conditions, which can be used for non-volatile storage. The work was supported by the Academy of Finland through the Finnish Center of Excellence “Computational Molecular Science” and the FinNano Project “Optical and Surface Properties of Nanoparticles”. Cooperation with Sergei Novikov, Timur Nikitin, Olli Kilpelä, Jouko Lahtinen, Rama Velagapudi, Markku Räsänen, Juha Sinkkonen, Claudio Oton, Daniel Navarro-Urrios, Eero Haimi, and Lorenzo Pavesi is gratefully acknowledged.

1Silicon Nanophotonics: Basic Principles, Present Status and Perspectives, edited by L. Khriachtchev (World Scientific, 2008);

2L. Khriachtchev et al. Appl. Phys. Lett. 83, 3018 (2003); 3L. Khriachtchev et al. Appl. Phys. Lett. 94, 043115 (2009); 4L. Khriachtchev et al. Appl. Phys. Lett. 86, 141911 (2005); 5L. Khriachtchev et al. Appl. Phys. Lett. 88, 013102 (2006); 6T. Nikitin et al. Appl. Phys. Lett. 94, 173116 (2009).

22

NOVEL NANOCOMPOSITE MATERIALS BASED ON MESOMORPHIC GLASSES OF METAL ALKANOATES:

STRUCTURES AND NONLINEAR-OPTICAL PROPERTIES

G. Klimusheva1, Y. Garbovskiy1, S. Bugaychuk1, A. Tolochko1, T. Mirnaya2

1 - Institute of Physics NASU, Kiev, Ukraine 2 - Institute of General and Inorganic Chemistry NASU, Kiev, Ukraine

klimush@iop.kiev.ua

To demands of fast recording and processing of large amount of optical information we propose novel nanocomposite materials, namely ordered mesomorphic glasses of metal alkanoates. The salts of the metal-alkanoates form a smectic A mesophase by heating, which is easy subcooling with creating the ordered mesomorphic glasses. The layered smectic A has the following structure: electrostatic cation-anion layers and bi-layers of alkanoate chains. The mesomorphic glasses are universal matrixes for many organic and inorganic nanoinclusions as well as for nanosized crystals. We develop preparation technologies for several different cells based on mesomorphic glasses, and investigate their structures by X-ray method and nonlinear optical properties. Impulse laser technique is used for nonlinear optical experimental studies. (1) Mesomorphic glasses on the base of La+3(C5H11COO)3 doped by organic dyes. Our technology permits to introduce into the mesomorphic matrix the dyes with different molecular structures (polymethine dyes of anion type, of cation type and neutral ones). Doped impurities do not distort the structure of the mesomorphic glass as the impurity molecules are built up well inside the matrix. It was shown that the doped impurities determine the nonlinear-optical properties of the whole cells, but the matrix provides fast relaxation of the heat. (2) Mesomorphic glasses of Co(II) alkanoates. We investigate the homological series CoCn+1, where n=7,9,11 and the common structural formula is Co2+(CnC2nCOOH)-2.These cells are colored, but we do not observe the nonlinear absorption effects. The recording of phase dynamical grating is found in these cells. It was shown that the refractive index change is caused by change of coordination states Co(II) at the action of laser radiation. Gigantic values of the nonlinearity are obtained during this process, the diffraction efficiency can reach ~1% with the cell thickness ~10-20 µm. (3) The salts of the Cd alkanoates with nanoparticles of semiconductor CdS are synthesized for the first time. On their base the mesomorphic glasses are prepared that contain nanosized crystals CdS inside their electrostatic layers. Absorption and luminescent spectrums are investigated in these novel materials. We demonstrate that investigated novel materials posses high value of the optical nonlinearity, they have fast times both for the recording and for the relaxation of holographic gratings. They are perspective materials for creating high-speed telecommunication devices on their base.

23

ELECTROLUMINESCENCE OF ORGANIC MOLECULES IN BLUE-GREEN AND RED RANGES OF THE SPECTRUM

T.N. Kopylova1, G.V. Mayer1, R.M. Gadirov1, K.M. Degtyarenko1,

A.V. Egorova2, N.S. Eremina1, A.V. Kukhto3, S.B. Meshkova2, Z.M. Topilova2, V.F. Shul’gin4, L.G. Samsonova1

1 - Tomsk State University, Tomsk, Russia

2 - Physical Chemical Institute NASU, Odessa, Ukraina 3 - Institute of Physics NASB, Minsk, Belarus

4 - Tavriya National University, Simferopol, Ukraina kopylova@phys.tsu.ru

The development and synthesis of organic V. F.4 molecules that can luminesce effectively in thin films through which electric current flows remain urgent problems of organic electronics. This work presents results of synthesis and investigation of photo- and electroluminescence of some optical compounds of rare-earth organic elements (Eu(TTA)3, Eu(TTA)3·Phen, Eu(TTA)3·(TPPO)2, Tb(AA)3·(TPPО)2, and Yb(TTA)3·(ТPPО)2, where ТТА is used for tenoyltrifluoroacetone, Phen for phenanthroline, TPPO for triphenylphosphineoxide, and АА for acetylacetone), diphenylbenzoxazolyl biphenyl (DBB-4,4′-bis[-1-(1,3-benzoxazole-2-yl-2-ethynyl)] biphenyl and its substitutes) and coordinated Zn compound with an organic ligand. All substances were synthesized using original techniques. The spectral and luminescent properties of the compounds were investigated in solutions and films prepared by centrifugation with the help of an Evolution-600 spectrophotometer, an SM 2203 spectrophotometer-spectrofluorimeter, and a Cary Eclipse spectrofluorimeter. The film morphology was investigated using a Nicolet Centauris 600 IR microscope and a Solver HV atomic power microscope. The ITO/PEDOT/PVC:X/CaMg/Ag electroluminescent structures were synthesized, where X is used for the above-enumerated examined compounds. Polyvinylcarbazole (PVC) was used to prepare films by centrifugation. Organic layers and cathodes were deposited using VUP-5 and AUTO-306 facilities. The film thickness was controlled by the known methods. The electroluminescence spectra were registered with an Avantes fiber spectrometer, and the current-voltage and brightness-voltage characteristics were registered using a specially designed stand. Laws of changing the spectral and luminescent properties of the examined compounds in films were established depending on the compound structure. The electroluminescence spectra are investigated, and the nature of the observed emission bands is discussed. The emission spectra of the examined molecules cover a wide wavelength range from dark blue (diphenylbenzoxazolyl biphenyl) to near-IR (Yb (TTA)3·(TPPO)2).

24

LEPR STUDY OF CHARGE TRANSFER PHOTOINDUCED IN POLYMER/FULLERENE BULK HETEROJUNCTIONS

V.I. Krinichnyi, E.I. Yudanova, N.N. Denisov

Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia

kivi@cat.icp.ac.ru

Electronic processes carrying out in bulk heterojunctions formed by poly(3-alkylthiophene) (P3AT) and fullerene derivative, [1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61] (PCBM), attracts growing interest during last years due to perspective applications of the P3AT/PCBM composite in molecular electronics and photonic. The irradiation of such a system by visible light excites electron transfer from polymer chain to the fullerene molecule accompanied by the formation of the paramagnetic polaron P+• and fullerene anion-radical C61

–•. The power conversion efficiency of such solar cells should obviously depend on dynamics properties of these paramagnetic centers. In the present report are discussed the first results of the light-induced EPR (LEPR) study of P3AT/PCBM composites with hexyl (P3HT) and dodecyl (P3DDT) alkyl substitutes irradiated by laser beam with photon energy of 1.8 – 3.4 eV at 77 – 200 K. LEPR spectra of radical pairs photoinduced in the P3AT/PCBM system directly in the spectrometer cavity was shown to consist of two lines at g1 = 2.0023 and g2 = 2.0001 attributed to the polaron P+• and fullerene anion-radical C61

–•, respectively. These radicals recombine at T > 180 K and the rate of such a process is governed by the laser photon energy. A decay of long-living radical pairs photoinduced in P3AT/PCBM composites was interpreted to depend strongly on a spatial distance between photoinduced charge carriers. The long lifetimes are solely ascribed to the long spatial distances that build up among the remaining photoinduced charge carriers, which did not recombine at a shorter time. At the increase of microwave field in a spectrometer cavity these spectra are broadened, so then both the spin-lattice and spin-spin relaxation times were determined by the steady-state saturation method. The polaron diffusion along and between polymer chains as well as the rotational diffusion of fullerene ion-radicals induce an additional magnetic fields in the whereabouts of electron and nuclear spins which, in turn, accelerates electron relaxation in both spin ensembles. This allowed to determine separately all these dynamics parameters. The dynamics of both the photoinduced charge carriers was interpreted in terms of their activation hopping over energy barriers Eb. The analysis showed that at the increase of photon energy from 1.88 eV up to 2.22 eV and then up to 2.75 eV the value of Eb of polarons photoinduced in P3DDT/PCBM composite first decreases from 65 meV down to 44 meV and then increases up to 95 meV. In the same time this value of fullerene molecules decreases monotonically from 24 meV down to 9 meV and then down to 6 meV. These energetic parameters obtained for P3HT/PCBM composite are characterized by extremal dependence on the photon energy near 2.0 and 3.1 eV. This can be a result of the formation of charge carriers in heterogeneous domains of this composite. Inhomogeneous ordering of such domains originates a variety of their band gap and, hence, sensitivity to photons with defined but different energy. The temperature annealing of P3HT/PCBM enhances its dimensionality (crystallinity) due to the formation of polymer crystallites and fullerene clusters that improves main electronic properties of plastic solar cells. The strategy of a creation of plastic solar-cells with optimal energetic is discussed. This work was partly supported by the Russian Foundation for Basic Research (Grant No 08-03-00133) and the Human Capital Foundation (Grant No 27-02-5).

25

OPTICAL AND ELECTROPHYSICAL PROPERTIES AND APPLICATIONS OF ORGANIC AND ORGANIC-INORGANIC

THIN FILM NANOSTRUCTURES

A.V. Kukhta

B.I. Stepanov Institute of Physics NAS, Minsk, Belarus kukhta@imaph.bas-net.by

Thin film nanostructures based on π-conjugated organic compounds and their combination with inorganic nanoparticles attract wide attention of researchers owing to both the unique properties and the possibility of manifold practical applications. In such nanostructures the optical and electrophysical properties depend essentially on molecular structure and solid state organization. In this talk a short review on the studies of some optical and electrophysical properties and applications of organic and organic-inorganic thin film nanostructures made in the B.I. Stepanov Institute of Physics of the National Academy of Sciences of Belarus jointly with other researchers are presented. The effect of the substrate nature, the molecule structure, and the deposition rate on optical and luminescent properties, morphology and photostability, is shown using dibenzoxazolylbiphenyl derivatives as typical example. It was revealed the reversible molecular reorganization resulting to the formation of partially ordered structures with luminescence polarization and radiating ability depending on the film temperature below the glass transition. The presence of oxygen was found to cause the essential luminescence quenching. The effect of adsorbed oxygen on electrophysical properties of some organic thin film nanostructures was also found. New electroluminescent materials based on dibenzoxazolylbiphenyl derivatives as well as doped and grafted polymers, conducting and cathodoluminescent nanocomposites, nitrogen dioxide sensor, etc. are proposed. The different kind additives are widely used to change polymer properties. The examples of additives are conductor (metal) or semiconductor (organic and inorganic) nanoparticles with a shell from organic material. We found that insertion of aromatic thiol into the shell of silver and gold nanoparticles in thin films based on polyepoxypropylcarbazole matrix results in the conductivity increase several orders of magnitude depending on temperature. IR spectroscopy data are the evidence of the formation of bond between SH functional group and nanoparticle surface. The strong conductivity dependence on oxygen concentration has been observed for polythiophene-Au nanoparticles nanocomposite. Cathodoluminescence of the composite based on polyfluorene and CdS nanoparticles was observed. New electroluminescent materials based on dibenzoxazolylbiphenyl derivatives as well as doped and grafted polymers, conducting and cathodoluminescent nanocomposites, nitrogen dioxide sensor, etc. are proposed.

26

EFFECT OF J-AGGREGATES ON OPTOELECTRONIC PROPERTIES OF CONDUCTING POLYMERS

E.I. Maltsev, D.A. Lypenko, O.M. Perelygina, S.I. Pozin, A.V. Vannikov

A.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia

eugenemalt@rambler.ru

We have revealed that one of the types of molecular organic crystals, known as J-aggregates, are able to modify dramatically optoelectronic properties of electroactive polymers. Polyaniline (PANI) was used as an efficient hole-conducting matrix belonging to the most important and widely used conducting polymer materials. PANI is particularly perspective, as functional material, in polymer optoelectronics, for example, in manufacturing multilayer organic light-emitting diodes (OLEDs). So far PANI was successively used in OLEDs as efficient p-type injection layer. Here we report on the electroluminescent properties of the composites based on a new conducting form of PANI, a water-soluble interpolymer complex obtained by a matrix method for the first time. As a nanophase-dopant we took J-aggregates of cyanine dyes. These nanosized particles are effective electroluminescent centers in polymer composites, thanks to their ability of accepting energy of the excited states. PANI water-solubility allowed using it as electroactive polymer matrix compatible with the J-aggregates nanophase. Being ionic salts, cyanine dye molecules easily giving molecular crystals (J-aggregates) in aqueous solutions. Because these nanosized particles have numerous geometrical forms (one-, two, and three-dimentional structures) and strongly affect optoelectronic properties, the study of the J-aggregates-based composites in water-soluble conducting matrices is of particular importance. It follows from our data that that electroluminescent behavior of the PANI/J-aggregates composites in the light-emitting layers of polymer light-emitting diodes (PLEDs) differs completely from that of all other systems. In particular, no electroluminescence was observed in PANI layers in the absence of nanoparticles. With a gradual increase in J-aggregate concentration in the PANI layers, a shortwave electroluminescence band appears, with a maximum at 400 nm. Its shape is identical with that of the PANI photoluminescence. The occurrence of the PANI intrinsic electroluminescence in the presence of J-aggregates is explained by combining different special features of the components constituting the nanocomposite and determining entirely the system’s unusual optoelectronic behavior. Among these special features, we first of all mention the PANI redox-heterogeneity, that is, the simultaneous presence in the polymer bulk of p-type conducting areas and photoluminescent light-emitting nonconducting ones. The study of PANI layers by the Kelvin-microscopy confirmed the redox-heterogeneity of the polymer. On the other hand, J-aggregates play a crucial role in the composite. These particles demonstrate effective electron-hole transport; they may have different geometrical form depending on the structure of cyanine dye molecules. According to AFM-data, J-aggregates used in this study form very thin (0,95 – 1,1 nm), wide ribbons. Thus, light-emitting polymer composites based on the J-aggregate-nanocristal-doped PANI are prepared and studied. Intrinsic electroluminescence of the PANI is recorded for the first time. It emits in the blue region. The observed emission is due to the polymer red0x-heterogeneity, as well as the structural and electron-hole-transport properties of the J-aggregate nanocrystals. This work was supported by the International Scientific and Technical center (project no. 3718).

27

FABRICATION OF NANO SPACE FOR CONTROL OF INCIDENT LIGHT FIELD

H. Masuda1, T. Kondo2

1 - Tokyo Metropolitan Univ./KAST, Tokyo, Japan

2 - KAST, Kanagawa, Japan masuda-hideki@c.metro-u.ac.jp

The fabrication of functional optical devices based on the ordered structures from submicron to nanometer scales has attracted increasing attention due to its applicability for various fields. We describe here the results of the preparation of highly ordered anodic porous alumina and its application to the fabrication of various nano-spaces, which can control the electric fields of incident light. Anodic porous alumina, which is formed by anodization of Al in acidic solution, is typical self-ordered material [1,2]. Anodic porous alumina with highly ordered nanohole arrays can be used for the preparation of several types of functional optical devices. Ordered hole array structures are promising for the preparation of two-dimensional (2D) photonic crystals, due to the highly ordered periodic structure [3,4]. Anodic porous alumina with hole array of submicron lattice constant exhibited a 2D photonic band gap in the visible wavelength region. The observed gap in the transmission spectra of the anodic porous alumina showed good accordance with the calculated value. Anodic porous alumina with highly ordered hole array structures can also be used for the various kinds of plasmonic devices [5,6]. The ordered metal structures prepared from highly ordered anodic porous alumina show unique optical properties originated from the localized surface plasmon, which was dependent on the size and shapes of the structures. [1] H. Masuda and M. Satoh, Jpn. J. Appl. Phys., 35, L126 (1996). [2] H. Masuda and K. Fukuda, Science, 268, 1466 (1995). [3] H. Masuda, M. Ohya, H,. Asoh, and M. Nakao, Jpn. J. Appl. Phys., 38, L1403 (1999). [4] H. Masuda et al., Adv. Mater., 18, 213 (2006). [5] F. Matsumoto, M. Ishikawa, K. Nishio, and H. Masuda, Chem. Lett., 34, 432 (2005). [6] T. Kondo, K. Nishio, and H. Masuda, Appl.Phys. Express, 2, 032001 (2009).

28

LASER AND ORGANIC NANOPARTICLES

H. Masuhara

Nara Institute of Science and Technology, Japan and National Chiao Tung University, Taiwan masuhara@masuhara.jp

Studies on organic nanoparticles have received much attention, and new preparation, novel phenomenon, interesting dynamics, and important optical property of molecular nanocrystals and polymer nanospheres are being examined extensively by utilizing lasers and microscopes. Indeed a new stage of nanophotonics research is being opened by integrating photochemistry, optics, and nano/bio materials studies (1, 2). Here we report some of our recent developments and discuss the relevant progresses. The top-down method for preparing very small organic nanocrystals is laser ablation in solution. Their size, shape, of phase can be controlled by tuning laser wavelength, pulse width, fluence, repetition rate, and shot number, and by changing solvent and temperature. The smallest size is 13 nm, which is obtained by fs irradiation (3). It is important to understand optical properties of nanoparticles as functions of their size, shape, internal structure, and environmental condition. Light scattering and fluorescence spectroscopic system coupled with AFM was developed and applied to single nanoparticles on substrate, some of which was already presented in the Terenin Symposium 2006 by us (4). This single nanoparticle spectroscopy is now extended to single nanoparticles in solution by combining microspectroscopy with laser trapping technique (5). Assembling of nanoparticles in solution was achieved by laser trapping with a focused intense near infrared CW laser beam. The assembling dynamics was probed by fluorescence and fluorescence correlation spectroscopies (6) and prepared materials were analyzed.. When the laser trapping is accompanied with the deformation of solution surface and convection in solution, molecular crystallization is induced, which was first demonstrated for glycine in heavy water (7). We are now exploring new molecular systems showing “Laser Trapping Crystallization” and studying their dynamics and mechanism by time-resolved spectroscopy and imaging. <References> (1) H. Masuhara, H. Nakanishi, K. Sasaki Ed. “Single Organic Nanoparticles”, 2003, Springer. (2) H. Masuhara, S. Kawata Ed., “Nanophonics: Integrating Photochemistry, Optics, and Nano/Bio Materials Studies”, 2004, Elsevier. (3) T. Asahi, T. Sugiyama, H. Masuhara, Accounts Chem. Res., 2008, 41, 1790H. (4) Masuhara, T. Asahi, “Spectroscopy and photochemistry of single organic nanoparticles”, Abstracts of the A. N. Terenin Symposium 2006. (5) Y. Tanaka, H. Yoshikawa, H. Masuhara, J. Phys. Chem. B., 2006, 110, 17906. (6) C. Hosokawa, H. Yoshikawa, H. Masuhara, Phys. Rev. E, 2005, 72, 021408. (7) T. Sugiyama, T. Adachi, H. Masuhara, Chem Lett., 2007, 36, 1480-1481; 2009, 38, 432

29

QUANTITATIVE ANALYSIS OF PH AND METAL IONS SENSITIV E PHOTOCHROMIC SPIROPYRANS AND SPIROOXAZINES

J.C. Micheau

CNRS, University Toulouse III, France

micheau@chimie.ups-tlse.fr

There is considerable interest in photochromic molecules such as spiropyrans, spirooxazines, azobenzenes, fulgides and diarylethenes. They undergo photochemically triggered changes in optical absorption, charge or ion chelation ability. Hence, they could find potential applications in various areas, from Life sciences to Environmental sciences and information processing technologies. When bearing appropriate chelating functional groups or heterocycles, spiropyrans are able to bind and release metal-ions in response to light stimuli. Their metal ion affinity can be modulated according to their closed spiro or open merocyanine states. There is thermochromic equilibrium between the two states. However, in presence of metal-ions such as Co(II), Ni(II), Cu(II), Zn(II), Cd(II), etc., asymmetrical Job diagrams confirmed the presence of several coupled equilibria related to the formation of various spiropyran/metal complexes. Combination of independent low temperature NMR measurements of the thermochromic equilibria and numerical modelling of the absorbance vs time curves recorded during metal-ion complexation allowed us to determine the various spectral, kinetic and thermodynamic parameters of the metal chelation. Photochromic spirooxazines often exhibit similar properties. If their solutions are acidified, they slowly turn intensely red. This spectral change has been attributed to the formation of the mono-protonated merocyanine. By turning the UV light on and off and adjusting the pH, such systems are able to switch between three forms (closed, open and open protonated) modulating their response as a function of several external inputs, thus mimicking logic gates behaviour. Their ability of metal-ion or proton scavenging under UV irradiation followed by their release under visible light makes the photochromic spiro-compounds very versatile to find applications. For instance, in analytical chemistry, on-line micro-fluidic devices based on spiropyran or spirooxazine photochromism and ionochromism could be realised to demonstrate the photonically controlled accumulation and release of ions.

30

CALIXARENE-BASED COMPLEXES AS PROMISING LUMINOPHORE S FOR LUMINESCENT SILICA NANOPARTICLES

A.R. Mustafina, S.V. Fedorenko, O.D. Konovalova, A.I. Konovalov

A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan SC RAS, Kazan, Russia

asiyamust@mail.ru

Luminescent nanoparticles are of particular interest nowadays due to their wide application in biochemichal analysis, medicine and nanophotonics.

Two main ways of getting luminescent nanoparticles are commonly used. The first way is to fix luminophores on a nanoparticles surface through covalent bonding, the second way is a doping luminophores within a nanopartcles core. The second way is more preferable, since it does not prevent further modification of a nanoparticles surface by anchoring groups, which is of particular importance in the development of biomarkers. We have chosen the second way to obtain the silica coated Tb(III) nanoparticles, exhibiting high and stable in time luminescent properties. The high

luminescence of Tb(III) doped nanoparticles is the result of Tb(III) coordination with p-sulfonatothiacalix[4]arene (TCAS), which is acting as the efficient antennae for Tb(III)-centered emission. The quenching through the ion exchange of Tb(III) by H+ or La(III) is time-dependent, indicating that the ion exchange is probably diffusion controlled. The quenching by Co(III) complex cations is achieved by energy transfer mechanism and thus is not time-dependent. The analysis of quenching data in Stern-Volmer cooordinates reveal the negative charge of silica coated Tb(III)-TCAS nanoparticles and several types of luminophoric species, located within the core and close to the surface of silica nanoprticles. The advantages and perspectives of the use of lanthanide complexes with various sulfonated calix[4]arene derivatives as luminophores for the synthesis of luminescent silica nanoparticles are discussed. We thank RFBR (grant N 07-03-00282) and BRHE REC 007 for financial support. 1. Skripacheva, V. V.; Mustafina, A. R.; Rusakova, N. V.; Yanilkin, V.V.; Nastapova, N.V.;

Amirov, R. R.; Burilov, V.A.; Zairov, et al, Eur.J. Inorg.Chem. 2008, 3957–3963. 2. A.R. Mustafina, S.V. Fedorenko, O.D. Konovalova, A. Yu. Menshikova, N.N. Shevchenko,

S.E. Soloveva, A.I. Konovalov, I.S. Antipin, Langmuir, 25, 2009, 3146-3151.

31

LOW -THRESHOLD TRANSFORMATION OF FREQUENCY IN SOLID SOLUTIONS OF Zn 0.6Cd0.4S

WITH ADSORBED METAL-ORGANIC CLUSTERS

O.V. Ovchinnikov, M.S. Smirnov, L.Yu. Leonova, E.A. Kosyakova, A.N. Latyshev, V.G. Kluyev

Department of Optics and Spectroscopy, Voronezh State University, Russia

opt@phys.vsu.ru

Working out the materials for the control and management of different parameters of the light stream with the help of the optical transitions and switches is a fundamental and important problem. Therefore, the materials in which anti-Stocks luminescence (ASL) is possible are really essential for solving such kind of problems. Semiconductor crystals with volume and surface metal and organic impurity centers, semiconductor heterostructures, systems with quantum dots and quantum gaps are considered to have the greatest potential. However, the thresholds of anti-Stocks transformations were high 1-103 W/cm2 in a lot of mentioned materials. In other cases the thresholds were not high 10-1-10-3 W/cm2 and the effect occurred at low temperatures (77–4.2 К) Possibility of low-threshold (10-2-10-4 W/cm2) anti-Stocks transformations of radiation with the wavelength 620 - 720 nm into the luminescence in the area 520 - 580 nm in small disperse crystals (SDC)of highly cleanliness solid solutions of Zn0.6Cd0.4S with adsorbed molecules of dyes and silver subnanoclusters at temperatures 77 - 300 K is described in this work. The spectral interval for the wavelength of radiation, which can be transformed into photoluminescence of Zn0.6Cd0.4S crystals, was determined from the ASL excitation spectrum. Comparing of these spectra with the spectra of the absorption of adsorbed molecules of dyes made it possible to determine the role of the dye molecules in the process of ASL excitation. The changes in the distribution of density of impurity surface states of SDС Zn0.6Cd0.4S as the result of the dye molecules and silver subnanoclusters adsorption on the surface of the crystals were under control. The method of infrared (IR) stimulated flash luminescence (SFL) was used for it. The spectrums of ASL excitation of these samples were completely positional identical to the spectrums of luminescence that was obtained with the UV excitation of the crystal in the area of the fundamental band of the adsorption. This fact proves that there is the same nature of the centers of radiated recombination of ASL and usual proper recombination luminescence of SDС Zn0.6Cd0.4S. The next important result of the work is the discovery of the effect of intensity change of ASL and, therefore, effectiveness of its excitation as a result of the influence of midget concentration of silver-containing solutions (10-6 – 10-8 mole AgNO3/moleZn0.6Cd0.4). It has been shown that the two-quantum inter-band optical transitions are realized sequentially with the transference of the energy of the electronic excitation from the dye molecule to the adsorbed on the surface Zn0.6Cd0.4S silver subnanoclusters forming deep local conditions with the photoionization energies of 1.80-2.00 eV in the forbidden gap. The evaluation of quantum effectiveness of the process of ASL was carried out taking into consideration the losses of luminescence while it was detected. Still it was 10-4 -10-5 for the streams 10-2 W/cm2 at room temperature. The authors acknowledge the funding support from the Russian Federal Property Foundation (through Grant No. 08-02-00744).

32

SUPRAMOLECULAR WATER-SOLUBLE COMPLEXES OF CAROTENOIDS

N.E. Polyakov1, T.V. Leshina1, E.S. Meteleva2,

A.V. Dushkin2, T.A. Konovalova3, L.D. Kispert3

1 - Institute of Chemical Kinetics and Combustion SB RAS, Novosibirsk, Russia 2 - Institute of Solid State Chemistry and Mechanochemistry SB RAS, Novosibirsk, Russia

3 - Department of Chemistry, University of Alabama, Tuscaloosa, AL, USA polyakov@kinetics.nsc.ru

Carotenoids are a class of pigments wide spread in nature, which also serve as an antenna, photoprotective device and intermediate electron carrier in photosynthetic reaction center. Carotenoid radicals play a crucial role in electron transfer and proton transfer processes in photosynthesis and in the design of improved artificial solar cells, as well as in the scavenging of toxic free radicals. At the same time, wide practical application of carotenoids is substantially hampered by their hydrophobic properties, instability in the presence of oxygen and metal ions, and high photosensitivity. Application of the “host-guest” inclusion complexes was first related to an attempt to minimize the aforementioned disadvantages of carotenoids when these compounds are used in food processing (colors and antioxidant capacity) as well as for production of therapeutic formulations considering the better solubility and consequently higher bioavailability. In the present work, we report the first example of water soluble carotenoid complexes with natural polysaccharide arabinogalactan (AG). It was demonstrated that incorporation of carotenoids into arabinogalactan macromolecule results in significant change in their properties. The increase of water solubility (up to 5 mM), photostability (a factor of 10 increase) and stability by a factor of 20 towards metal ions in solution has significant importance in the practical application of carotenoids [1]. In addition the protection of carotenoids from the reactive oxygen species by arabinogalactan was demonstrated. On the other hand, inclusion complexes of some carotenoids with natural triterpene glycoside, glycyrrhizic acid (GA), show enhanced ability (in orders of magnitude) to scavenge free radicals [2]. A very important observation is determining the effect of GA on the oxidation potential of carotenoids. The most interesting results were obtained on the study of photoinduced electron transfer between carotenoid complexes and TiO2 nanoparticles in solid state and in solution. An important result of these studies is the considerable increase in the yield and stability of the radical cation of carotenoid in solid state AG complex, and significant increase in the yield of free radicals in solution. High stability of the carotenoid radical cation imbedded into nanosized polysaccharide host opens wide possibilities of the application of these complexes for design of artificial light-harvesting, photoredox and photocatalytic devices. The financial support of Russian Foundation for Basic Research, grant 08-03-00372 and the U.S. Department of Energy, Grant DE-FG02-86ER13465 are also gratefully acknowledged. References: N.E. Polyakov, e.a. Water Soluble Complexes of Carotenoids with Arabinogalactan. J. Phys.

Chem. B 2009, 113, 275-282. N.E. Polyakov, e.a. Antioxidant and Redox Properties of Supramolecular Complexes of

Carotenoids with β-Glycyrrhizic Acid. Free Rad. Biol. Med. 2006, 40, 1804–1809.

33

BRANCHED AND DENDRITIC POLYARYLSILANES AS NANOSTRUCTURED LUMINOPHORES

S.A. Ponomarenko, N.M. Surin, O.V. Borshchev,

Y.N. Luponosov, E.A. Shumilkina, A.M. Muzafarov

ISPM RAS, Moscow, Russia ponomarenko@ispm.ru

One of the prospective methods of organic nanostructured materials creation for photonic and optoelectronic devices is chemical coupling of chromophores into macromolecules having branched and dendritic structure. Luminescent dendrimers, having dimensions in the range of several units to several decades of nanometer, show unique optical properties: huge molar extinction coefficient, “molecular antenna” effect, record high photo- and electroluminescent efficiency [1]. In this work a new approach to formation of polyarylsilanes of branched and dendritic structure, consisting from oligoarylene fragments of different conjugation length, linked to each other through silicon atoms being also the branching points. Preparation of these compounds is based on the combination of organometallic reactions leading to aryl-aryl coupling (Suzuki, Kumada) with organosilicone chemistry (reaction of chloro- and alkoxysilanes with organolithium and organomagnesium thiophene derivatives). Investigation of the optical properties of the compounds obtained revealed that silicone atoms brakes the conjugation between the adjacent oligoarylene fragments, but their presence in the dendritic structure can increase the

luminescence efficiency in 10-15 times [2]. For the first time among organosilicone compounds the effect of “molecular antennae” was shown for the dendrimers consisting of different oligothiophenesilane fragments within the same macromolecule [3]. This effect means that the whole macromolecule absorbs photons in the wide spectral region, then efficient intramolecular energy transfer takes place, and only the fragments with the largest conjugation length, located in the center of the molecule, emits the light (Fig.1). Peculiarities of the optical properties of such compounds will be considered in the presentation. Preliminary results have shown good properties of functional layers made from polyarylsilanes of branched and dendritic structure in different devices: organic light emitting diodes, photovoltaic cells, plastic scintillators.

Authors thanks for financial support Russian Foundation for Basic Research (grant 07-03-01037), Russian Federal Agency for Science and Innovations (contract No. 02.513.11.3382) and Russian Academy of Sciences (Program Presidium 27). [1] S.A. Ponomarenko, O.V. Borshchev, Y.N. Luponosov, A.M. Muzafarov, Luminescent

dendrimers, All Materials, Encyclopedic Hand-book, 2008, 2, с.13-22; 3, с.36-45. [2] Y.N. Luponosov, S.A. Ponomarenko, N.M. Surin, A.M. Muzafarov, Organic Letters 2008,

10, 2753-2756. [3] Y.N. Luponosov, S.A. Ponomarenko, N.M. Surin, O.V. Borshchev, E.A. Shumilkina, A.M.

Muzafarov, Chemistry of Materials 2009, 21, 447-455.

H13C6

H13C6

S

S

S

S

S

CH3Si

SS

Si

S

C6H13

S

S

S

S

CH3Si

SS

S

C6H13

C6H13

S

S

S

S

CH3Si

S S

CH3

C6H13

H13C6

H13C6

S

S

S

S

S

CH3Si

SS

Si

S

C6H13

S

S

S

S

CH3Si

SS

S

C6H13

C6H13

S

S

S

S

CH3Si

S S

CH3

C6H13

Fig.1. Structural formula of the first organosilicone dendrimer –

“molecular antennae”

34

THE EFFECT OF METALIC NANOPARTICLES ON THE OPTICAL CHARACTERISICS OF PORPHYNATES AND MEH-PPV SOLUTIONS

A.A. Revina1, M.G. Tedoradze1, Yu.A. Plachev1, I.V. Bogdanova2

1 - A.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia

2 - D.I. Mendeleev University of Chemical Technology of Russia, Moscow, Russia revina@mail333.com

Spectrophotometric investigation of the metallic nanoparticles interactions with different porphyrinates and with light-sensitive polymer, poly- 2-metoxy-5-(2-ethylgexyloxy)-1,4-phenyllenvinylene, MEH-PPV in the organic solutions were performed in order to learn the influence of different additives on the solar energy absorption and the energy transformation by photoactive polymer layers. Prior to it, optical absorption and luminescence spectra of Ag, Pd, Pt nanoparticles, and spectra of the MEH-PPV and porphyrinates Pd(II) and Pt(II) in the solutions were determined. Stable metal nanoparticles in liquid phase were produced in reverse Н2О/АОТ/аlcane micelles as microreactrs using radiation-chemical method at “Lanacom Ltd.” laboratory [1]. The porphyrinates were synthesized at IPCE New Physicochemical Problems Laboratory [2]. UV-VIS Specord (Shimadzu) was used for optical absorption spectra measurements. Fluorescence spectra registration was performed with Hitachi F-7000 spectrometer. To determine reciprocal influence of Pt, Pd nanoparticles and selected porphyrinates, various volumes of reverse micellar solutions with ω=[Н2О]/[AOT]) containing metal nanoparticles, with initial metal ion concentration of ~ 4.0х10-4 М were added to optically sensitive light porphyrinates. In case of Ag nanopartiles, the study was done using solutions with metal concentration increased by order of magnitude, while ω values varied from 1.5 to 8.0. There is a known dependency between fluorescence emission quenching capabilities and photovoltaic parameters of energy converters. Our study has proved that admixture of Pt(II) ions to the porphyrines (H2TCP) does not make impact on its luminesce characteristics, while addition of Pt nanoparticles (NP) to porphyrine PdТСР solution causes quenching of luminescence in the range of ~ 660 nm. Along with porphyrine’s luminescence quenching the buildup of Pt NP’s luminescence was observed (λмах~ 510-540 nm). Similar effect was determined during examination of Pt NP and Pt porphynates (PtTCP) interaction. In case of Pd NP related study, the intensity of the main porphyrinte luminescence band (λmax1=660nm) increased by 15%. Addition of Ag NP to PdТСР has shown only decrease of luminescence band (λmax1=660 nm). Or study of reciprocal influence of PtТСР and Ag NP reveled NP size effect on decrease of fluorescence intensiy. Voltaic data measured for photosensitive МЕН-РРV layers prove that the addition of Ag NP, synthesized I reverse micelles with ω0=5, most efficiently increase the photovoltaic parameters of the layers, and causes luminescence quenching. 1. Patent RF 2147487, priority date as of 20.04.2000. 2. A.Yu. Chernyad’ev, N.M. Logacheva, A.Yu. Tsivadze// Journal of Inorganic Chemistry.

2005. Vol. 50. 4. P.615. The research is supported by grants of RFBR 08-03-00796 and 09-08-00758.

35

SPECTRAL AND LUMINESCENT PROPERTIES OF SEVEREL ACRIDINE COMPOUNDS IN SOLUTIONS AND SiO 2-FILMS

L.G. Samsonova, N.I. Selivanov, T.N. Kopylova, V.Ya. Artyukhov, T.A. Solodova

Tomsk State University, Russia

slg@phys.tsu.ru

Optical chemical sensors that use luminescence, including changes of the radiation intensity, radiation wavelengths, spectral shape, and luminescence life-time possess high sensitivity and selectivity toward molecules of different analytes. The targeted search of compounds exhibiting sensor properties and the design of optical sensor materials on their basis is a topical task. The acridine dyes are suitable compounds for creation of a material for an optical sensor. The spectral, luminescent properties, dipole moment in base and in excited states, photophysical processes of deactivation of excitation energy for acridine, 9-aminoacridine and 2,7-dimethyl-9-ditolylaminoacridine (9-DTAA) and for their protonated forms were investigated experimentally and using quantum mechanical simulation. It was shown that in this molecules the nitrogen of acridine cycle is a protonation site. The more strong changes of spectral properties under protonation were observed for acridine: the fluorescence maximum considerably shifted in the red region and a fluorescence quantum yield increased up to 0,27 (for neutral form it is equal 0,03). For a 9-DTAA protonated form the fluorescence is absence. In results of carried out quantum-chemical calculations it was shown that for investigated molecules the lowest singlet and triplet states have ππ* orbital nature and very week fluorescence for acridine and protonated 9-DTAA is result of strong singlet – triplet conversion. For acridine protonated form the rate constant of singlet – triplet conversion decreases on several degrees. So considerable change of spectral-luminescent properties enables to use acridine protonated form as the active medium for detection of small amount of substances with the basic properties, for example ammonia. Suitable material for a matrix of an optical sensor is the material made from tetraethoxysilane (TEOS) received sol-gel method and doped with organic compound (acridine). Since in synthesis acid hydrolysis was used acridin was in protonated form.in the final product The sensor material was made in form of thin (< 1 µm) films by spin-coating method. To study the capability of the received material to be a sensor for ammonia the investigation of fluorescence spectra behavior of samples doped the acridine at contact with ammonia vapor was carried out. In result of interaction ammonia vapor with film surface the fluorescence intensity of protonated acridine fall down. It was caused by greater basicity of ammonia in comparison with a molecule acridine, that leads to transition of a proton from acridine nitrogen to a molecule of ammonia at their contact. The dependence of ammonia vapors concentration on fluorescence intensity was investigated. Thus, the possibility of creation of optical sensors on the basis of organic compounds incorporated in thin silicate films was shown.

36

OPTOELECTRONIC SENSOR SYSTEMS BASED ON THIN FILM ORGANIC ELECTRONICS

H.F.M. Schoo1, M.M. Koetse1, P.A. Rensing1, G.T. Van Heck1,

N.N.M.M. Meulendijks1, M. De Kok1, P.G.M. Kruijt1, F.P. Wieringa2

1 - Holst Centre 2 - TNO

herman.schoo@tno.nl

In many practical applications, the ideal sensor device would be thin, lightweight and flexible. These are properties, generally attributed to Thin Film Organic Electronic Devices, which makes them a good candidate for future sensor applications. (Combinations of) devices like organic light emitting diodes (OLED), Organic Field Effect Transistors (OFETs) and organic photodiodes (OPD) may be used to create innovative sensors. Furthermore, they would preferably be cheap, so that (high end) disposable sensors would become an option. Therefore we set out to develop an optical sensor platform having OLED, OPD and organic circuitry modules as core elements. The fabrication technology for these modules is developed to be compatible with mass production, and will be based on printing and reel-to-reel processing. Here, we show that OLEDs and OPDs can be used in a wide range of optical sensors. Printing technologies allow for cheap production of devices. Using a modular build up of these and additional components such as organic circuitry and/or embedded thinned silicon dies will allow for an almost two-dimensional design with a variety of resulting products. As an example the design and the fabrication of modules for a pulse-oximeter device and integration into a wireless smart bandage will be discussed.

37

FULLERENE NANOCLUSTERS AS AMPLIFIERS IN LINEAR SPECTROSCOPY AND NON-LINEAR OPTICS

E.F. Sheka

Peoples’ Friendship University of Russia, Moscow, Russia

sheka@icp.ac.ru

The enhancement of linear and non-linear optical properties results from two filed effects referred to as field confinement and field resonance. Thus, arranging the space around or nearby a polarizable object in a manner of either open (caves and planar structures) or closed (droplets) nanocavities influences a particular spatial distribution of the field around the object that causes an enhancement of the light emitted by the object. On the other hand, a strong increase of spontaneous and stimulated emission of the object additionally occurs when either incoming or outgoing field is resonant with local excitations of the cavity atomic structure. While the first field effect has been studied for various kinds of materials, the resonance effect is mainly limited to nanoparticle-structured metals, such as silver and gold, so that the resonance with local plasmons has been considered. However, not only plasmons but Wannier-Mott excitons as well as charge transfer excitons may provide a considerable polarization of the medium under excitation and thus may cause a considerable enhancement of optical properties of an object placed inside or near a nanocavity made of the corresponding materials. Nevertheless, studies of this kind are rather scarce and are related to semiconductive species characterized by Wannier-Mott excitons. The paper presents first results related to the field resonance effects caused by charge transfer excitons. This concerns the study of fullerene nanoclusters that present nano-sized charge transfer complexes immersed in a molecular solvent. Excited by different laser wave lengths exλ , the clusters manifest clearly seen enhancement of Raman scattering and

one-photon luminescence when either exλ or emλ is resonant with local charge transfer excitons.

The light emission emλ concerns both cluster themselves as well as surrounding solvent

molecules which makes the spectral evidence of the enhanced effects quite variable and dependent on the chemical structure of fullerene molecules [1-3]. The experimental findings are in good accordance with the electromagnetic theory of enhancement [4] which allows for linking directly linear and non-linear optical properties. The latter lays the foundation of practically important criteria that allow predicting non-linear optical behavior of the medium on the basis of its linear spectral properties. The work is financially supported by the RFBR (grants 07-03-00755 and 08-03-01006). References

1. B.S.Razbirin, E.F.Sheka, A.N.Starukhin, D.K.Nelson, P.A.Troshin, R.N.Lyubovskaya, JETP Lett. 87, 133 (2008)

2. E.F.Sheka, B.S.Razbirin, A.N.Starukhin, D.K.Nelson, M.Yu.Degunov, L.N.Lyubovskaya, P.A.Troshin, JETP. 108, 738 (2009).

3. E.F.Sheka, B.S.Razbirin, A.N.Starukhin, D.K.Nelson, M.Yu.Degunov, P.A.Troshin, R.N.Lyubovskaya. J.Nanophot. SPIE 3, 033501 (2009)

4. J.P.Heritage, A.M.Glass, Surface Enhanced Raman Scattering. p.391, Plenum Press: NY and London (1982).

38

FEMTOSECOND PRIMARY CHARGE SEPARATION IN PHOTOSYSTEM I

I.V. Shelaev1, F.E. Gostev1, M. Mamedov2, O.M. Sarkisov1, V.A. Nadtochenko1,

V.A. Suvalov3, A.Yu. Semenov2

1 - ICP RAS 2 - IPCB MSU 3 - IFPB RAS shelaev@bk.ru

In the last years, electron transfer reactions in photosystem I (PS I) were studied very strongly using various ultrafast techniques, including pump-probe absorption spectroscopy. However, the primary electron transfer reactions within PS I reaction center (RC) could not be clearly separated from excitation energy transfer since these reactions occur within the same time range. Nevertheless, one approach was developed to separate electron transfer from energy transfer and to reveal the pure kinetics of primary electron transfer steps and the spectra of corresponding intermediates. Femtosecond experiments were carried out on setup created in Laboratory of Bio- and Nanophotonics in Institute of Chemistry Physics Russian Academy of Scientists. The energy and electron transfer in PS I was studied by femtosecond pump-probe absorption spectroscopy. The excitation was performed using 20-fs laser pulses centered at 720 nm. The predominantly selective excitation of the special pair P700 chlorophyll (Chl) in the RC results in the appearance of the spectra of the primary radical pair P700+A0

-A1 (where A0 is the primary Chl electron acceptor and A1 is the secondary phylloquinone acceptor) with main bleaching bands at 690 and 705 nm within 100 fs. The subtraction of kinetic difference absorption spectra of the closed (state P700+A0A1) RC from that of the open (state P700A0A1) RC reveals the pure spectrum of the P700+A0

- ion-radical pair. Experimental data were analyzed using simple kinetic scheme:

An* → 1k (P*A0A1 →< fs100 P+A0-A1) → 2k P+A0A1

- , and the global fit procedure based on the singular value decomposition analysis. The calculated kinetics of transitions between intermediate states and their spectra coincided very well with the kinetics recorded at 694 and 705 nm and the experimental spectra obtained using subtraction of the spectra of closed from the spectra of open RCs. As a result, we found that the main events in RCs of PS I under our experimental conditions include very fast (<100 fs) conversion of P700*A0A1 to P700+A0

-A1 state in apprximately half of RCs, the ~5-ps energy transfer from antenna Chl* to P700A0A1 in the remaining part of RCs and ~25-ps formation of the secondary radical pair P700+A0A1

-.

39

ELECTRONIC SENSORS ON THE BASIS OF NANOSTRUCTURED CERIUM OXIDE FILMS

A.N. Shmyryeva, A.V. Borisov, N.V. Maksimchuk

National Technical University of Ukraine «KPI», Kyiv

lejanel@ukr.net

The influence of technological parameters of nanostructured cerium oxide films preparation on the electronic and structural properties was studied with the purpose of their application as an active element of different microelectronic sensors: high-performance photoresistors and MOS – photodiodes for bioluminescence registration, ion-selektive field-effect transistors (ISFET) and MOS - varaktors indicating the pH changes as a result of biochemical processes. X-ray photoelectron spectroscopy (XPS) analysis showed that, the ratio of Се3+ and Се4+ concentrations in the CeOx films vary depending on the technological parameters, foremost, substrate temperature, that cause change of fundamental gap Eg. The correlation of these changes with the optical and photo-electric characteristics was set. On the basis of the developed highly sensitive photodetectors and living organisms (Daphnia magna and bioluminescent bacteria) a portable electronic biolumenometric complex has been created for determination of the overall toxicity, caused mycotoxin patulin, pesticides bifentrin and chlorpyrophos. The minimum threshold of sensitiveness for patulin is 0,1 mg/l after 2 h. and 0.01 mg/l after 6 and 24 h. of experiment, bifentrin – 0.01 mg/l after 3 h. and 0.0001 mg/l after 24 h. of experiment. It was shown that the application of nanocrystalline cerium oxide films as a dielectric of MOS - structures promotes a sensitiveness and sensors stability due to the high density of the sensible sites on the CeOх surface (to 1020 м-2), large value of dielectric constant (ε=26) and Eg (3.6 eV), low values of leakage currents. The results of application of ISFETs and MOS - varaktors with nanocrystalline CeOх film for creation of immune and enzyme biosensors were demonstrated. Threshold of sensitiveness for enzyme sensors on the basis of cholinesterases to phosphoorganic pesticides is 10-9 M, to the ions of heavy metals is 10-7 M. A рН-sensitiveness of the ISFET - 58 мV/рН, that close to the maximally possible sensitiveness for a structure semiconductor-dielectric-solution, so-called Nernst sensitiveness – 59 мВ/рН.

40

UV-LIGHT STIMULATED FORMATION OF ORGANIC NANOPARTICLES

G.I. Skubnevskaya, S.N. Dubtsov, G.G. Dultseva

Institute of Chemical Kinetics and Combustion SB RAS, Novosibirsk, Russia

skubnev@kinetics.nsc.ru

The report deals with the investigation of the mechanisms of formation of organic aerosol under photolysis of the compounds of different classes. The kinetics of photolysis and a complicated sequence of elementary stages following the primary photoexcitation was investigated. The yields of photonucleation were measured for aldehydes (formaldehyde, avetaldehyde, benzaldehyde), amines and halogenated aromatics. Reactive intermediates - short-lived free radicals were identified, gaseous and aerosol products were analyzed. Photonucleation was studied with the help of the Diffusion Aerosol Spectrometer developed at ICKC SB RAS. Investigations were carried out in a flow photochemical quartz reactor in the flow an inert carrier gas and in the presence of additives: oxygen, ozone, water vapour. The kinetic data of the investigated systems were compared with the results of physicochemical analyses of the initial compounds, intermediate and final products in the gas phase and in aerosol, down to the trace amounts. Mathematical modeling of photolysis at the level of elementary stages and numerical modeling of photonucleation in coagulation mode with permanent photochemical source of the nuclei of the dispersed phase, involvement of the electronic databases on chemical kinetics allowed us for the first time to obtain the quantitative data on the yields of the initial stages of photonucleation. The yield varies within the range ~ 10-1 to 10-6 in the investigated systems. The contribution from the photonucleation of gaseous organics into the formation of nanoparticles in the Earth’s atmosphere was estimated. The nonlinear dependencies of the dimensional and concentration characteristics of the formed nanoparticles on photolysis parameters and on the chemical composition of reaction mixtures were investigated. These data will open the way to directed synthesis of organic nanoparticles of required size and composition for various applications, including biotechnologies and medicine. The investigation has been supported by SB RAS (1982-2004), Russian Foundation for Basic Research (1994-2009) and CRDF (2002-2004).

41

MATERIAL SOLUBILITY AND MISCIBILITY EFFECTS IN FULLERENE/POLYMER COMPOSITES USED AS

PHOTOACTIVE MATERIALS IN ORGANIC SOLAR CELLS

P.A. Troshin1, E.A. Khakina1, D.K. Susarova1, H. Hoppe2, A.E. Goryachev1, A.S. Peregudov3, N.S. Sariciftci4, V.F. Razumov1

1 - IPCP RAS, Russia

2 - TU Ilmenau, Germany 3 - INEOS, Russia 4 - LIOS, Austria

troshin2003@inbox.ru

Organic photovoltaics have been subject for intensive research worldwide for the last decade. As a result, the power conversion efficiencies of the fullerene-polymer solar cells were boosted in 2006-2007 to a commercially interesting level of 5-6 % starting from values of 0.04 % in 1993. At the moment there is a race to develop novel fullerene-based and polymer-based photoactive materials that can improve efficiency of organic solar cells. However, now there are no detailed explanations in literature how the molecular structure and the properties of the materials correlate with their performance in solar cells. In this talk we will report results of our systematic investigation of numerous conjugated polymer/fullerene derivative composites as active layer materials in organic solar cells. Thirty novel fullerene-based electron acceptor materials were synthesized and evaluated in organic bulk heterojunction solar cells with poly(3-hexylthiophene) P3HT as electron donor component. We show that there is a good correlation between the solubility of the fullerene derivatives in organic solvents used for film casting and the output parameters of organic solar cells made using composites of these compounds with P3HT as active layer materials. In particular, the best performances were obtained for fullerene derivatives possessing solubilities comparable to the solubility of P3HT (ca.50-90 mg/ml) (Figure 1). Twelve fullerene derivatives possessing different solubilities were combined with poly(3-alkylthiophenes) bearing side chains of varied length: P3BT (C4), P3HT (C6), P3OT (C8), P3DT (C10) and P3DDT (C12). Investigation of the resulting 60 fullerene/polymer composite systems in organic solar cells revealed important material structure/solubility – solar cell performance relationships that will be discussed in this talk. In conclusion, the performed systematic investigation of numerous fullerene/polymer composites revealed important rules for design of advanced material combinations for organic photovoltaics.

Figure 1.

42

PEPTIDES AGGREGATES AS SUPRAMOLECULAR NANOSYSTEMS. STRUCTURE INVESTIGATIONS BY PULSED ELECTRON-ELECTRO N

DOUBLE RESONANCE (PELDOR) SPECTROSCOPY

Yu.D. Tsvetkov, A.D. Milov, R.I. Samoilova

Institute of Chemical Kinetics and Combustion SB RAS, Novosibirsk, Russia Tsvetkov@kinetics.nsc.ru

The PELDOR technique will be represented. It is shown that by analyzing the kinetics of PELDOR signal decay due to magnetic dipolar interactions it is possible to fined the distance between paramagnetic centers in a pairs, distance distribution function F(r) in the range 15–70 Å, to identify the radical assembling in groups and to estimate the number of the radicals in the groups. The distances determination by PELDOR in different systems will be exemplify. Data on the structure of supramolecular aggregates of spin-labeled trichogin dimmer, zervamicin and alamethicin in apolar solutions will be presented together with its structural changes when peptide/biolayers interaction is taking place. This work was supported by the Russian Grant for Scientific Schools (НШ-551.2008.3), the Russian Foundation of Basic Research (RFBR grant 06-04-48021-a), grant of Programme 7 Dep. of Chem. and Matherials RAS.

43

NON-LINEAR OPTICAL AND PHOTONIC CRYSTALLINE CHROMOPHORE-CONTAINING POLYMERIC MATERIALS

FOR OPTOELECTRONICS AND OPTOSENSORICS

A.V. Yakimansky1, G.I. Nosova1, N.A. Solovskaya1, N.N. Smirnov1, N.A. Nikonorova1, A.Yu. Menshikova1, N.N. Shevchenko1, T.G. Evseeva1,

S.P. Gromov2, S.K. Sazonov2, A.V. Koshkin2, V.A. Sazhnikov2, M.V. Alfimov2

1 - Institute of Macromolecular Compounds RAS, St.Petersburg, Russia 2 - Photochemistry Center RAS, Moscow, Russia

yak@hq.macro.ru

Non-linear optical (NLO) nanostructured materials are of great interest for optoelectronics because they make it possible to change the frequency of the propagating light and to realize a communication between electric and optical signals through their light-perturbed electronic distribution. In the present work, copolymethacrylates, polyimides, polyamidoimides, and polyimidourethanes with covalently attached chromophore groups were synthesized. Second harmonic generation (SHG) coefficients, d33, for corona-poled films of these polymers were measured. It was shown that for polyimidourethanes with imbedded 3,4-dicyanoazobenzene chromophore groups the value of d33 exceeds 100 pm/V, making these materials perspective for optoelectronic applications. For copolymethacrylates, the processes of orientational relaxation of the chromophore groups, determining the poling efficiency and, therefore, the level of achievable second order NLO properties, were studied using the method of dielectric spectroscopy. 3D-ordered photonic crystalline arrays of monodisperse polymeric nanoparticles functionalized with covalently attached or electrostatically adsorbed chromophores are perspective materials for optoelectronics, telecommunication industry and optosensorics. Monodisperse submicron poly(styrene-co-methacrylic acid) particles with surface carboxylic groups were obtained by emulsion copolymerization. Photonic crystalline films of these particles were prepared with cationic dyes (Rhodamine 6G and 1-(3-ammonium-propyl)-4-[(E)-2-(3,4-dimethoxyphenyl)-1-ethenyl]pyridinium perchlorate) adsorbed onto their negatively charged surfaces. These films displayed photonic band gaps, overlapping at definite directions of incident light with their fluorescence band. Besides, the fluorescence intensity changed reversibly in the vapors of polar solvents. This effect is perspective for design of matrix chips of gas sensors ensuring simultaneous detection of several analytes. The work is supported by the Federal Agency on Science and Innovation of the Russian Federation (contract 02.513.12.3025) and by the Scientific Program “Basic research of nanotechnology and nanomaterials” of the Presidium of the Russian Academy of Sciences.

44

FORMATION PRINCIPLES AND RELAXATION PROCESSES IN NANOSCALE HETEROGENEOUS COMPLEXES:

MULTIPORPHYRIN ARRAYS AND CdSe/ZnS NANOCRYSTALS

E.I. Zenkevich1, C. Von Borczyskowski2

1 - National Technical University of Belarus, Minsk, Belarus 2 - Institute of Physics, Chemnitz University of Technology, Chemnitz, Germany

zenkev@tut.by

It is clear that well-defined geometry is one of the important factors requisite for enhanced light-harvesting efficiency and/or ultrafast vectorial electron transfer in natural and artificial systems. With this idea in mind, we have elaborated the formation (in solutions and polymeric PMMA films at 295 K) various types of self-assembled nanoscale multiporphyrin arrays of controllable geometry and composition (up to 8 tetrapyrroles) using non-covalent two-fold binding interactions of the meso-phenyl bridged ZnOEP chemical dimers or trimers, (ZnOEP)2Ph or (ZnOEP)3Ph2, with di- and tetrapyridyl substituted tetrapyrrole extra-ligands.

The dynamics and mechanisms of relaxation processes in multiporphyrin arrays as a function of redox and photophysical properties of interacting subunits have been studied in solvents of various polarity and temperature (77-295 K), using static, time-resolved picosecond fluorescent (experimental response ∆1/2 ≈ 30 ps) and fs pump-probe (∆1/2 ≈ 120 fs) set-ups.

The strong quenching of the fluorescence for (ZnOEP)2Ph or (ZnOEP)3Ph2 is governed by competing energy migration (EM) and photoinduced electron transfer (PET) processes to the extra-ligand (∼0.9 ps). In arrays containing pentafluorinated extra-ligands PET takes place within ∼700 fs and remains still efficient in rigid solutions at 77-120 K. In the case of covalently linked electron acceptors (A) of the non-porphyrin nature (quinone, pyromellitimide), the strong S1-state decay shortening (fluorescence quenching) of the dimer is due to EM and PET processes to the extra-ligand (∼0.9-1.7 ps), which are faster than a slower PET «dimer→A» (34-135 ps) in toluene at 295 K. In these conditions, the extra-ligand S1-state decay (τS=940-2670 ps) is governed by competing processes: a bridge (dimer) mediated long-range (rDA=18-24 Å) superexchange PET to an acceptor, and photoinduced hole transfer from the excited extra-ligand to the dimer followed by possible superexchange PET steps to low-lying CT states. Inspired by work on self-assembled multiporphyrin arrays we have succeeded in the direct labelling of TOPO capped semiconductor nanocrystals (NC) CdSe/ZnS with tetra-pyridyl substituted porphyrins, (H2Pm-Pyr)4, based on the coordination of the pyridyl N lone pair with QD surface Zn or Cd atoms. Although part of the porphyrin-induced QD photoluminescence (PL) quenching could be explained by Foerster resonant energy transfer “NC→porphyrin”, more than 85% of the PL quenching is caused by the other reason. It was shown that at the same molar ratios x = [H2P(m-Pyr)4]/[NC], the quenching is more effective for small NCs than for larger ones. Based on the comparison of experimental Stern-Volmer quenching plots )(/0 xII and quantum

mechanical calculations for the electron single-carrier wave functions, we conjecture that the specificity of the exciton non-radiative decay in “NC-porphyrin” nanocomposites is due to the manifestation of inductive and mesomeric effects leading to the charge tunnelling through the ZnS barrier in the conditions of quantum confinement.

This work was supported by Belarus Program Nanoteckh 6.18, Volkswagen-Stiftung Grant No I/79 435 and ECO-NET Project (program No 18905YD).

Electron Transfer

Energy Transfer

45

POSTERS

PHOTONICS OF THE NON-CONJUGATED POLYARYLENEPHTHALIDES – NEW POLYMER CLASS

FOR ELECTROLUMINESCENCE DEVICES

V.A. Antipin1, A.N. Lachinov2, A.S. Nakaryakov2, S.N. Salazkin3, A.A. Kovalev2, V.P. Kazakov3

1 - Institute of Organic Chemistry URC RAS, Ufa, Russia

2 - Institute of Physics of Molecules and Crystals URC RAS, Ufa, Russia 3 - Institute of Elementoorganic Chemistry RAS, Moscow, Russia

lachinov@anrb.ru

Optical properties of the new polymer class, namely, polyarylenephthalides, are discussed in this paper. This polymers are known as a substances which demonstrate different electrical effects. The main condition for this phenomenon is one dimension of the experimental devise must be no greater than Debye wavelength for this material. This electrical effect is electrical switching induced by different physical fields (electrical, magnetic fields, temperature and pressure) [1]. During this phenomenon high conductivity state appears in the insulator film. This conductivity depends on the external actions. Bipolar injection of charge carrier in to thin films permits to realize electroluminescence (EL). Spectrum of this EL emission coincides with the photoluminescence spectrum in this case. But the mechanism of this photoluminescence is not clear. Thus, in this paper the results of the optical properties investigation are presented. The investigation is based on the analyze of the photoluminescence spectrum, phosphorescence, excitation spectrum and adsorption spectrum. Influence of the excitation energy on the spectrum has been studied. It is observed that shift of the excitation wavelength at 200 nm results in shift of the emission band at 160 nm to the red zone (fig. 1). This phenomenon demonstrates possibility of the energy properties of the injection to manage the wavelength in case of the EL. Possible mechanisms of changing the polyarylenephthalides optical properties by UV-illumination are discussed in the report.

Fig. 1. Dependence of the radiation wavelength in the excitation wavelength. Percentage of the PPB 1.2% in the methylene chloride

Excitation wavelength, nm

Radiation wavelength, nm

46

MODELING OF NONLINEAR-OPTICAL ACTIVITY OF POLYMER ELECTRET AND RELAXATION STABILITY

OF ITS QUADRATIC RESPONSE

M.Yu. Balakina

A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan SC RAS, Kazan, Russia marina@iopc.knc.ru

Polymer material exhibiting electrical response due to the incorporated organic dipole chromophores is in the electret state resulting from the orientation of chromophore groups in the applied electric field. Material in the electret state is characterized by the macroscopic polarization which is determined by the orientational order of the chromophores. In the polymer electret organic chromophores are in the locally anisotropic polarizable deformable environment. It is necessary to elaborate new models and approaches for the description of the medium effect on the chromophore nonlinear optical (NLO) response. In [1-3] we have proposed original analytical approach to the modeling of polymer electret NLO response, which is based on the special ansatz defining the cavity occupied by the chromophore in the material. The cavity is chosen to be conformal to the characteristic ellipsoid of the generalized permittivity tensor of the material, virtual medium inside the cavity being either isotropic or anisotropic. In the framework of the model the local electric field affecting the chromophore in the electret is obtained. This field depends on the applied electric field, macroscopic polarization of the electret, dielectric properties of the medium, as well as on the chromophore electric moment, multipole (quadrupole and octupole) contributions being taken into account in addition to the dipole contribution. The obtained equation establishes relationship between the electret macroscopic polarization and molecular electric characteristics of the chromophores (dipole moment, polarizability and hyperpolarizability). Analytical equations for the pyroelectric, piezoelectric and electrostrictive coefficients of the material are obtained on basis of polymer electret macroscopic polarization. To study the stability of the polymer NLO electrets quadratic response, which is directly connected with the relaxation of chromophores orientation order, we have suggested an evolutional model accounting for the interrelation of electric, rheological and thermal processes in polymer material. The distinguishing feature of the model is the use of non-stationary equations taking into account pyroelectric, piezoelectric and electrostrictive effects [2, 3]. Retardation of the response is described by the integro-differential operators of the special type; one of the models uses the so-called Kohlrausch-Williams-Watts extended exponents. The main attention is given to the relaxation model of two-dimensional polymer film. [1]. M.Yu. Balakina. Chem Phys Chem 2006, 7, 2115-2125; [2]. M.Yu. Balakina. J Non-Cryst Solids 2007, 353, 4432-4436; [3]. M.Yu. Balakina. Russ Chem Bull 2008, 57, 7, 1-5. The work is performed under financial support of Russian Foundation for Basic Research (projects 08-03-01108-а and 09-03-00696-а).

47

CONTINUUM MODEL FOR ELECTROSTATIC ENERGY OF INTERACTION OF A DIPOLAR ION OR DIPOLAR MOLECULAR

SYSTEM IMMERSED IN A SPHERICAL NANOPARTICLE

M.V. Basilevsky1, E.A. Nikitina2, F.V. Grigoriev3, M.V. Alfimov1

1 - Photochemistry Center RAS, Moscow, Russia 2 - Institute of Applied Mechanics RAS, Moscow, Russia

3 - Research Computing Center, Moscow State University, Moscow, Russia basil@photonics.ru

A method for a theoretical calculation of the electric response field, generated in a spherical nanoparticle after immersion in it a dipolar ion or dipolar molecular system was elaborated. The new algorithm for solving the Poisson's equation, implemented and tested in the Photochemistry Center, Russian Academy of Sciences was applied. It focuses on the study of electrostatic effects of polarization and interaction in non-inform continuous dielectric medium. The non-uniformity of the environment is introduced as a variable dielectric permittivity of the medium. For simple objects (a spherical ion and a two-sphere dipole) a dependence of implantation of free energies on the particle position and orientation within the nanoparticle is calculated. These energetic profiles show a singularity (a deep narrow well) in passing through the surface of a nanoparticle. Similar calculations are performed for several polar molecules, and for a typical organic dye. Under financial support of RFBR 07-03-00479-а

48

OPTICAL CONTROL OF NANOPOROUS POLYMERS SYNTHESIS PROCESS FROM PHOTOPOLYMERIZABLE COMPOSITES

M.A. Batenkin, A.N. Konev, S.N. Mensov, S.A. Chesnokov

G.A. Rasuvayev Institute of Organometallic Chemistry RAS, Nizhny Novgorod, Russia

mensov@iomc.ras.ru

As a rule, photopolymerizable composites (PPC) contain non-polymerizable compounds. The most of organic solvents are not compatible with three-dimensional polymers synthesized from the PPC based on acrylic oligomers. Considerable quantity of non-polymerizable compounds in the PPC mixture can result in micro- and nanoscaled ruptures of polymeric net due to oligomer and solvent true solution transforming into polymer-solvent heterogeneous medium. Consequently, nanopores can be formed in the volume of polymeric glass during the PPC hardening in the presence of solvent [1]. The porous polymer can be used both, as a filter for gases and liquids and as a material for visible and infrared optics. The cavities in volume of the nanoporous polymer can be filled, for example, by inorganic component with high refractive index. This allows to produce material with high optical density. The size and morphology of the pores depend on concentration and chemical nature of non-polymerizable additive, as well as on the polymerization reaction rate. The last one can be controlled by the intensity of influencing light upon the photoinitialization. In this paper the influence of initiating radiation intensity on nanoporous polymeric structure synthesized from the PPC is under investigation. The PPC based on oligoether(meth)acrylate OCM-2 was used for experimental research. Polymeric structures formed during the photopolymerization process were analyzed by the method of atomic-force microscopy and microscopes Solver P47 and Smena-A were used. A porous structure forms in the volume of the polymer if concentration of the solvent is more than 20 – 25 mas.% (for methyl alcohol additive). The most homogeneous structure with the minimal size of pores (~ 200 – 300 nm) forms if content of non-polymerizable compound is about 30 mas.%. The size of pores enlarges with the solvent content increase. We studied the intensity influence on morphology of forming pores for the following conditions: concentration of methanol in PPC was 30 mas. % and intensity was varied in the range from 1 kLx to 50 kLx. The size of formed pores is obtained to be non-monitonically dependent on the intensity (fig. 1). There is an optimal value of influencing light intensity, when the porous structure is the most homogeneous and the size of pores is minimal (~ 200 nm). This work was supported by the RFBR (grant 08-03-12090, 08-03-97055 and 09-03-00668). [1] Batenkin M.A., Konev A.N., Mensov S.N., Chesnokov S.A. Nanostructuring of polymers

upon photopolymerization in the presence of neutral component // The third international school of chemistry and physical chemistry of oligomers. Moscow – Chernogolovka – Petrozavodsk, June 2007, p. 61.

ρ, nm

I, kLx 10 30 0 0

200

400

Fig.1 – Dependence of the pores size ρ on the intensity I.

49

SYNTHESIS, SELECTIVE AND PHOTOLUMINESCENT PROPERTIE S OF THE DERIVATIVES OF TERPYRIDINES - EFFECTIVE

MOLECULAR RECEPTORS FOR ZINC(II) ION

V.E. Baulin, N.M. Logacheva, A.M. Safiulina, N.Y. Konstantinov, A.Y. Tsivadze

A.N. Frumkin Institute of Physical Chemistry & Electrochemistry, Moscow, Russia baulin@phyche.ac.ru

In present time the correlation between concentration of "ions of a life" in the cells of live organisms and occurrence of the certain pathologies is established. In particular, it is proved, that ions Zn2+ provide the important biological functions in cells and lifetime measurement of their concentration allows spending early diagnostics of some diseases. One of the ways of measurement of concentration of ions Zn2+ in vivo is the use of the opportunities of fluorescence with application of the organic fluorescenting receptors, which capable selectively to connect ions Zn2+ at surplus of ions Na+, K+, Mg2+ and Ca2+, and spectral-kinetic characteristics of fluorescence of free and connected of the receptor ions Zn2+ should provide an opportunity of quantitative measurements under physiological conditions. Besides these compounds must possess the low photo-toxicity and comprehensible solubility in physiological environments. In the present work we developed an effective method of synthesis earlier not described derivatives of 2,2':6',2"- terpyridines (I-V), possessing by additional coordinating fragments of crown-ethers and o-phosphorylphenols, that opens opportunities for purposeful designing metalocomplexing supramolaculary systems with the necessary fluorescenting properties.

The structure of compounds (I-V) is confirmed by the NMR 1Н and 31Р spectroscopy and the element analysis. For compounds (IV) it is executed the X-Ray analysis. The primary testing of the ability of (I-V) selectively to connect ions Zn2+ was spent by a method of the liquid extraction from the modeling physiological solutions. The concentrations of ion Zn2+in the initial and equilibrium solutions were determined by inductively coupled plasma mass-spectrometry (ICP-MS). For the most perspective

compounds the parameters of spectra of absorption and a luminescence as function of concentration of the ions Zn2+ have been investigated. The set of the extraction measurements and characteristic changes of spectra of absorption and emission allows to consider, that derivatives of 2,2':6',2"- terpyridines (I-V) can be used for creation of selective photoluminescent molecular receptors for definition of ion Zn2+ in physiological environments. Work is executed at financial support of the program of basic researches of Presidium of the Russian Academy of Science «Development of methods of reception of chemical substances and creation of new materials» and the Grant of the RFFI 09-03-01208-á

N N N

R

I, R=NH2; II, R=O

O

O

OOO

OO

O

OOIII, R= O

IV, R=

OH

PPhPh

ON

N

OH

PPhPh

ONNV, R=

I-V

50

PHOTOLUMINESCENT PROPERTIES OF FLUORENE-SUBSTITUTED PORPHYRINS

A.Yu. Chernyadyev, Yu.A. Plachev, A.Yu. Tsivadze

A.N. Frumkin Institute of Physical Chemistry & Electrochemistry, Moscow, Russia

chernyadyev@mail.ru

Complexes of metals with porhyrins of different structure can be applied as active components of electronooptic devices (photovoltaic convertors, electroluminescent devices) and systems for singlet dioxigene generation. New complexes of transition metals (Ni, Pd, Pt) and nontransition metals (Mg, Al) with fluorene-substituted porphyrins have been prepared. Influence of metal nature on the luminescent properties of tetrapyrrolic core of metal fluorene-substituted porphyrins have been estimated. It was found magnesium and aluminum fluorene-substituted porphyrins manifest more intensive fluorescence as compared of free base porphyrin and can be promising components of red light emitted elecrofluorescent devices. Palladium and platinum fluorene-substituted porphyrins manifest weak fluorescence as compared of starting free base porphyrin due to enhancement of IC transitions by heavy atoms of palladium and platinum. These compounds can be perspective as active components of electrophosphorescent devices and can be active in singlet dioxygen generation process. The work was supported by RFBR grant 07-03-13547 and ISTC project “Development of Materials and Processes for High Technology Organic Devices”.

51

PHOTOCHROMISM OF MEROCYANINE COMPLEXES OF DIPHENYLOXAZOL CONTAINING SPIROPYRANS

WITH TRANSITION METAL CATIONS

A.V. Chernyshev1, A.V. Metelitsa1, E.B. Gaeva1, N.A. Voloshin2, V.I. Minkin1

1 - Institute of Physical and Organic Chemistry, Southern Federal University, Rostov-on-Don, Russia

2 - Southern SC RAS, Rostov-on-Don, Russia anatoly@ipoc.rsu.ru

The mechanism of photochromic rearrangements of spiropyrans is related to thermally and photochemically reversible heterolytic cleavage of Сspiro-О bond of cyclic isomer A followed by cis-trans-isomerisation into metastable merocyanine form. The presence of partial negative charge on the oxygen atom of merocyanine isomer makes it potential ligand in complexation reactions with metal ions [1]. One of the deactivation pathways of complexes excited states is their photodissociation into spiroform of ligand and a metal cation [2]. This phenomenon opens vast perspectives of spiropyran application in new fields. For example, it makes possible to control the process of target species binding in the sample with active surfaces of chemical sensors ‘on-line’ [3]. However, no literature is available on the quantitative estimation of the efficiency of complex photodissociation.

Recently, it has been shown that in solutions, spironaphthopyrans having diphenyloxazol substituent in the position 5’ form stable complexes of merocyanine isomer with transition metal cations [4]. It has been revealed that such complexes exhibit photochromic properties. Irradiation of

complex solutions with visible light induces their thermally reversible decoloration (fig. ). After switching off the irradiation source the system reverts to the initial equilibrium position. In this case the observable thermal relaxation rate constant is the same as the rate constant of complex formation. Therefore, it may be concluded that a photodissociation process takes place. Photodissociation reaction of complexes can be described by the followed equation:

)1( αα −−Φ=− ∆kIdt

dMB

where α − complex molar fraction, k∆ - complexation rate constant of pseudo-first order, Ф – quantum yield of photodissociation, IMB – intensity of the absorbed light. On the basis of the equation the values of photodissociation quantum yields of Zn2+ and Cd2+ merocyanine complexes has been calculated to be 0.04-0.15. This work was supported by the Ministry of education and science of Russian Federation (project No DSP.2.2.2.3.16008) and RFBR (project No 09-03-00813). References:

1. Alfimov M.V., Fedorova O.A., Gromov S.P. // J. Photochem. Photobiol. A: Chem. 2003. Vol. 158. P.183–198.

2. Chibisov A.K., Görner H. // Chem. Phys. 1998. Vol.237. P. 425-442. 3. Radu A., Scarmagnani S., Byrne R., Slater C., Lau K. T., Diamond D. // J. Phys. D: Appl. Phys.

2007. Vol. 40. P. 7238-7244. 4. Chernyshev A.V., Voloshin N.A., Raskita I.M., Metelitsa A.V., Minkin V.I.// J. Photochem.

Photobiol. A: Chem. 2006. 184. P. 289-297.

N O

R2

R1

R1 = H, Cl, OCH3

R2 = O

N Ph

Ph

0 50 100 150 200 250 3000,0

0,2

0,4

0,6

0,8

1,0

α

"light "off"

light "on"

t, s

52

MECHANOCHEMICAL PREPARATION OF WATER-SOLUBLE COMPLEXES OF CAROTENOIDS

V.I. Evseenko1, E.S. Meteleva1, A.V. Dushkin1, N.E. Polyakov2

1 - Institute of Solid State Chemistry and Mechanochemistry SB RAS, Novosibirsk, Russia

2 - Institute of Chemical Kinetics and Combustion SB RAS, Novosibirsk, Russia evseenko@solid.ncs.ru

Carotenoids are a class of pigments widespread in nature. Carotenoids are widely used as food dyes and biologically active additives, but their application is restricted by insolubility in water and low stability. Among the methods of the preparation of water-soluble forms of biologically active compounds the most well-known are the formation of intermolecular complexes with cyclodextrins, more often with β-cyclodextrin. Also it is known the method of preparation the colloid dispersions and emulsion of carotenoids, which include dissolution carotenoids at the increased temperature in organic solvents in the presence of surface-active substances. Imperfection of these methods are:

• Necessity of preliminary dissolution carotenoids in toxic organic solvent and the subsequent extraction of the formed complexes. • Significant duration of process, necessity of use of the expensive equipment and frequently recycling of waste products of the used solvents. • All received compositions are not dissolved in water, but form insufficiently stable water dispersions or emulsion which can be removed by usual filtration. The method of complex preparation used in the present work was a mechanochemical treatment of the solid mixture of carotenoid crystals with arabinogalactan powder. Typical mechanochemical reactions are those activated by co-grinding or milling of powder materials. As a complexant we used arabinogalactan - natural polysaccharide extracted from the Siberian larch and the Gmelin larch. The preparation and properties of similar complexes are described in [1, 2]. During mechanochemical treatment carotenoid molecules penetrate to arabinogalactan matrix from its initial crystal state, forming the solid solution representing disordered solid phase in which carotenoid and arabinogalactan molecules undergo non covalent not ionic interactions. During dissolution of this solid dispersion the complexes keep their structure. It was shown that formed nanosized complexes have essential advantages as compared with initial carotenoid. In particular, it was demonstrated a substantial increase in solubility of carotenoids (concentration of beta-carotene in the aqueous complex solution was approximately 2.5 g/l). The fact of significant increase of solubility carotenoid in mechanochemically prepared complexes is inherent to arabinogalactan and, according to the literary data, unknown or is absent for others complex-forming compounds. High stability of the radical cations of carotenoids in nanosized complexes polysaccharide arabinogalactan opens wide opportunities for application of these complexes for design of artificial photosynthetic and photocatalytic devices. 1. Patent RF 2006143081. A water-soluble medicinal composition and method of its

preparation. T.G.Tolstikova, G.A.Tolstikov, A.V.Dushkin, E.S.Meteleva. 2. A. V. Dushkin, E. S. Meteleva,T. G. Tolstikova,G. A. Tolstikov, N. E. Polyakov, N. A.

Neverova, E. N. Medvedeva, and V. A. Babkin. Mechanochemical preparation and pharmacological activities of water-soluble intermolecular complexes of arabinogalactan with medicinal agents // Russian Chemical Bulletin , International Edition , Vol. 57, 6, p. 1-9.

53

EFFECT OF THE CHROMOPHORES MUTUAL ORIENTATION ON NONLINEAR-OPTICAL RESPONSE OF MOLECULAR SYSTEM.

QUANTUM-CHEMICAL CALCULATIONS

O.D. Fominykh, M.Yu. Balakina

A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan SC RAS, Kazan, Russia fominykh@iopc.knc.ru

Interest in new polymer materials, whose nonlinear-optical (NLO) properties are determined by incorporated organic chromophores, is conditioned by their potential application in photonics and optoelectronics. The optimization of polymer material NLO properties requires thorough investigation of the effect of the chromophore groups mutual arrangement. We considered molecular systems with various ways of chromophores organization. The structure of clusters from two and three molecules of p-nitroaniline (PNA), coupled by the hydrogen bonds, thus promoting the increase of the system dipole moment, are investigated [1]. On the basis of performed quantum-chemical calculations of the clusters the cooperative effect was established at the formation of first hyperpolarizability (β): β of dimer increases 2.6 times, and β of trimer - 5.1 times as much as that of single chromophore. Additional increase of β is achieved by means of the solvent effect, accounted in the framework of the polarizable continuum model (PCM). To study the bearing chain conformation effect on the NLO response of the attached chromophore the hyperpolarizability of dimer on the basis of diglycidyl ether of bisphenol-A with dimethylaniline in each unit of the chain was evaluated. Characterististic conformations were selected in the course of conformation search by Monte-Carlo method [2]. The dimer β|| was established to exceed β|| of the chromophore fragment by ~70% due to mutual arrangement of the chromophores (the angle between them being ~60°). One of the ways of optmization of quadratic NLO properties of polymer material is the limitation of the possiblility of antiparallel arrangement of the chromophore groups, resulting in substantial decrease of the NLO effect. Creation of polymer materials on the basis of cross-linked dendrimers and hyperbranched polymers with dendrite groups is quite promissing in this connection. We calculated structure and hyperpolarizability, β, of model oligomers of dendrite type - bidendrons and tridendrons – with various unit lengths, containing different chromophore groups. The effect of linking the oligomer branches on its NLO characteristics was studied by the example of model non-cross-linked and cross-linked bidendrons on basis of dimethyldioxymethane with (4-dimethylamino-3’-oxymethyl-4’-nitro)azobenzene chromophore group in each branch, hexamethylenediisocyanate being used as cross-linking agent. The oligomer dipole moment was established to increase almost twice at cross-linking, due to decreasing the angle between the chromophores (by ~23°). Polarizability αav and the values β|| increase in the series chromophore - non-cross-linked oligomer - cross-linked oligomer, their values being 32.4⋅10-24 esu, 79.7⋅10-24 esu, 91.2⋅10-24 esu, and 36.7⋅10-30 esu, 41.1⋅10-30 esu, 46.4⋅10-30 esu, respectively. Electric characteristics – dipole moment and molecular polarizabilities of the studied systems – were calculated by TDHF/AM1 method using GAMESS programme. [1]. M.Yu. Balakina, O.D. Fominykh// Int.J.Quant.Chem., 2008, 108, 2678; [2]. M.Yu. Balakina, O.D. Fominykh, F. Rua, V. Branchadell// Int.J.Quant.Chem., 2007, 107, 2398. The work is performed under financial support of Russian Foundation for Basic Research (projects 08-03-01108-а and 09-03-00696-а).

54

INFLUENCE OF THE ORGANIC LIGHT-EMITTING DIODE STRUCTURE ON THE IR(PPY)3 ELECTROLUMINESCENCE

R.M. Gadirov, K.M. Degtyarenko, N.S. Eremina, T.N. Kopylova

Tomsk State University, Russia

kopylova@phys.tsu.ru

In the last few years it has been demonstrated that the use of phosphorescent organic materials in organic light-emitting diodes is promising due to the special features of excitation of their luminescence in an electric field []. The iridium complex Ir(ppy)3 is undoubtedly one of the promising electrophosphorus compounds []. This work presents results of investigations into the influence of the organic light-emitting diode structure on the Ir(ppy)3 electroluminescence. For the components of the electroluminescent compositions, we have chosen:

1. Ir(ppy)3 doped into polyvinylcarbasole (PVC) and polyfluorene (PFO) polymers, because the Ir(ppy)3 luminescence in a pure film is much weaker than in compositions with a polymer,

2. PEDOT (polystyrylsulfonate-1), 3 mass% in water, 3. TPD (N,N′-bis(3-methylphenyl)-N,N′-diphenylbenzylidene), 4. Alq3 (aluminum tris-(8-oxyquinolinate)).

The organic thin-film structures were prepared by the centrifugation method. Chloroform (CLF), chlorobenzene (CLB), and tetrahydrofuran (THF) were used as solvents. ITO was used as an anode (100Ω/cm2), and CaMg, Mg, and Al protected by an Ag layer were used as cathodes. The film thickness was measured with a Linnik (MII-4M) microinterferometer and a laser LÉF-757 ellipsometer. The electroluminescence spectra were registered with an Avantes CCD fiber spectrometer, and the photoluminescence spectra were registered with an SM 2203 spectrophotometer-spectrofluorimeter and a Carry Eclipse spectrofluorimeter. The current-voltage and brightness-voltage characteristics were registered with a special complex. The special features of the Ir(ppy)3 photoluminescence in various compositions were investigated. It has been demonstrated that the Ir(ppy)3 photoluminescence in PVC is caused by its phosphorescence (with a radiation lifetime of ~0.06 ms); total excitation energy transfer from PVC to Ir(ppy)3 was observed. The Ir(ppy)3 electroluminescence spectrum in PVC was similar to the photoluminescence spectrum. It was demonstrated that the electroluminescence characteristics (the threshold voltages at which electroluminescence was observed, luminescence brightness, running current density, and stability of characteristics) depend on the nature of the organic solvent used for film preparation, the nature of the employed film-forming polymer, presence of additional layers at the boundary with the electrodes, and the cathode material. The most promising electroluminescent structure has been established: ITO/PEDOT/PVC: Ir(ppy)3/LiF/CaMg/Ag.

55

MODEL OF ENERGY CONVERSION EFFICIENCY FOR POLYMER PHOTOVOLTAIC CELLS

D.Yu. Godovsky1, O. Inganas2

1 - Laboratory of Physical Chemistry of Polymers, INEOS RAS, Moscow, Russia

2 - IFM, Linkoping University, Linkoping, Sweden dmigo@yandex.ru

Here we present the calculation of the upper limits of energy conversion efficiency for D-A based polymer solar cells. There are a number of differences between D-A based polymer PV cells and the p-n junction based semiconductor ones: 1. Conjugated polymers are regarded to be one-dimensional semiconductors, hence the density of states for 1-D polymer differs dramatically from the density of states of 3-D semiconductor which is used for standard calculation of energy efficiency for semiconductor PV-cells. The dramatic difference in absorption coefficient dependence on photon energy determines the difference in the optimum for the efficiency of energy conversion 2.Practically all the authors calculating the efficiency of p-n junction cells assume the equilibrium emission from the photoexcited states of the semiconductor. This assumption is not valid from our point of view for D-A based polymer PV cells, due to two factors: First and the most important is that for D-A combinations, as in the case of polyphenylenevinylene(PPV)/C60 for example, the ultrafast non-radiative transfer takes place with the time constants ca 10

-13sec., which is around two orders of magnitude faster, than the

characteristic time for spontaneous emission from PPV. This causes luminescence quenching and totally destroys the equilibrium between photons in radiation subsystem and electron subsystem of the PV cell. The stability of this charge transfer extends up to ms, and reversibility is not an appropriate model. Therefore the D-A PV cells work under non-equilibrium condition and all the formulae obtained using thermodynamics principles like in Shokley-Quessier model are not valid in this case. 3. The third distinctive feature of D-A PV cells is the use of thin layers of polymers (10-300 nm), mainly because of the low charge mobility. The condition of thickness of the cell, which is assumed by most models, calculating the efficiencies of power conversion, is not the case for polymer cells. We made the calculations of the photovoltaic polymer cells efficiencies, assuming that the plastic D-A solar cells work simply as photon counters, and the energy of individual photon is not to be taken into account due to the very nature of the D-A transfer. The open circuit voltage to be considered is determined simply by the difference between the LUMO of donor and HOMO of the acceptor minus some part obtained theoretically, and the very fact of the D-A transfer “equalizes” the energy input from each photon, independently of it’s energy. The optimal value of Voc for given acceptor molecule can be calculated from the analysis of three energy level diagram: HOMO of conjugated polymer (E1), LUMO of polymer (E2) and HOMO of acceptor (E3). We used 1-D Density of States model, ideal lorentzian absorber model and some intermediate case. The results, obtained using the latter model (without correction for fill factor reduction) give the limit to efficiency of D-A plastic solar cell ca.17% in single band gap approximation. The drastic increase of the efficiency with the increase of absorbance peak width is associated by us with natural “multi-bandgap” phenomena, arising from the fact that the band gap value of most spin cast polymers varies due to the natural dispersion of conjugationlength.

56

PHOTOPHYSICAL PROPERTIES OF AQUEOUS SOLUTION OF 3,3’-DIETHYLTHIACARBOCYANINE IODIDE

IN THE PRESENCE OF CUCURBIT[7]URIL

D.V. Golubkov, D.A. Ivanov, N.Kh. Petrov, M.V. Alfimov

Photochemistry Center RAS, Moscow retmas@gmail.com

Photophysical properties of aqueous solution of cyanine dye (DTCI, 10-7 M) (fig. 1) was studied in the presence of cucurbit[7]uril (CB7) (fig. 2) by means of optical spectroscopy. Pumpkin-shaped macrocycle of CB7 has a rigid intermolecular cavity that determines its behavior as host-molecule. It allows including DTCI as the guest-molecule. The molecular dimensions of CB7 are as follows: the internal and external diameters are at 5.4 Å and 7.3 Å, respectively, the height at 9.1 Å [1]. It was found that upon addition 0.1mM of СВ7 in solution, DTCI absorption essentially changed (fig. 3). Assuming formation of host-guest complexes (1:1), we have determinated the associated constant К=2. 8 104 М-1, varying concentration of СВ7 and measuring absorption at 550 nm. Measurement of polarization of DTCI fluorescence has shown an essential increase in the effective volume of radiating molecules in the presence of СВ7. It is in a good agreement with the assumption of producing host-guest complexes. It was found that lifetime of DTCI fluorescence inside СВ7 increases 6 times in comparison with a homogeneous aqueous solution; it so doing quantum efficiency of the nonradiating relaxation of the electronic-

excited molecules of the DTCI in СВ7 increases approximately 8 times. Work was partially supported by the RFBR, the grant 07-03-00479.

REFERENCES J.W. Lee, S.Samal, N. Selvapalan, H-J. Kim, K. Kim, Acc.Chem.Res. 2003, vol.36, 621.

Fig. 1. Cyanine dye DTCI

Fig. 3. a – water solution of DTCI, b – at presence of CB7

Fig. 2. Cucurbit[7]uril molecule

57

TRIPLET-TRIPLET ENERGY TRANSFER IN NANODIMENSIONAL MOLECULAR LAYERS

N.Kh. Ibrayev, A.K. Aimukhanov, E.V. Seliverstova

Karaganda State University, Kazakhstan

nibraev@ksu.kz

Triplet-triplet energy transfer was investigated in the multilayer films. Aromatic molecules have been used as energy donors. Amphiphilic molecules of dyes served as energy acceptors. Triplet

energy donors had high quantum yield of intersystem crossing S1→T1. The filling of acceptor triplet states was not observed at direct excitation. Thin films of the energy donor have been received on a surface of nonluminescent quartz substrate by vacuum deposition or by Langmuir-Blodgett (LB) method. Dye monolayers were deposited by LB method on the surface of donor film. The number of the monolayers varied from 1 to 10. Measurements of donor and acceptor decay of the delayed luminescence were performed by photon-counting mode. Excitation was performed by N2−laser pulses in the energy donor absorption band. The measurements were performed at sample temperature Т = 90 К. While exciting in the anthracene absorption band, the bands of annihilation delayed fluorescence (DF) of the anthracene monomers (λmax = 500 nm) and excimers (λmax = 500 nm) were observed for pair anthracene−nile red. Besides, the band of sensitized DF of nile red was observed (λmax = 650 nm). The increase of the dye concentration in monolayer leads to quenching donor luminescence and to increase of acceptor DF intensity. Kinetics decay of the donor and acceptor luminescence has complicated form. The initial part of the kinetics decay curves is described by power function and long-time part by exponential function. Power function exponent of kinetics initial part of the donor annihilation DF is increase with the increase of the acceptor concentration. Kinetics decay of acceptor sensitized luminescence also depends on dye concentration. The increase of the anthracene concentration in monolayer leads to increase of intensity of acceptor. The highest radiation yield of acceptor is observed at donor concentration 50-60 molar %. Similar data are received and for pairs anthracene-rhodamine B and 1,2- benzanthracene-rhodamine B. Distance influence between layers of the donor and acceptor on energy transfer efficiency was studied. Separation of donor and acceptor layers was performed by layers of palmitic acid. The intensity of donor luminescence increases twice with increase in distance from 0 Å to 54 Å for the pair 1,2- benzanthracene-rhodamine B. The intensity of anthracene DF increases in 1.8 times at separation of anthracene and rhodamine B layers by 6 monolayers of polyampholytic polymer. The temperature influence on energy transfer was investigated. It is shown, that energy transfer efficiency between layers of the donor and acceptor depends on migration rate of donor exciton as a result of inhomogeneous broadening of donor molecules. The influence of external magnetic field on the property of the delayed luminescence donor and acceptor has been studied for ascertainment of a nature of sensitized luminescence of dyes. The limit value of the negative magnetic effect on DF of donor at 0.5 T is equal 16.3% for pair anthracene-rhodamine B. Magnetic field influences on the intensity of dye sensitized luminescence in a lesser degree. Maximal value of rhodamine B magnetic effect is 11.3 %. Influence of external magnetic field on dye sensitized luminescence is evidence of that the luminescence is the result of triplet-triplet exciton annihilation.

58

SPECTROSCOPIC PROPERTIES OF LANGMUIR FILMS OF RHODAMINE DYES AND POLYAMPHOLYTIC POLYMER

N.Kh. Ibrayev1, Zh.K. Smagulov1, V.I. Alekseeva2, L.E. Marinina2, L.P. Savvina2

1 - Karaganda State University, Kazakhstan

2 - Organic Intermediates and Dyes Institute, Moscow, Russia nibraev@ksu.kz

Nanodimensional films on a basis of amphiphilic molecules of rhodamine dyes (heptadecyl either of rhodamine B - dye I; 3,6-bis(octadecylamino)-9-o-carboxiphenyl) xanthyl perchlorate - dye II) and hydrophobic-modificated polyampholytic polymer have been received by Langmuir-Blodgett (LB) method. Mixed monolayers were formed at water–air interface using Langmuir trough. Monolayers were transferred onto quartz substrates by vertical dipping according to Z and Y types transfer at surface pressure of π=30 mN/m and the dipping speed through the monolayer 0,02 mm/s. The thickness of the films consisted of 20 monolayers. Absorption and fluorescence spectra of LB films from dye I are measured at various ratio of dye and polyampholyte molecules. The shape and position of the absorption bands of the dye LB films indicates on the formation of mainly plane dimers with a small number of sandwiches dimers. The existing of monomers also is visible. Decreasing of dye concentration in LB films leads to decreasing of the probability of both plane and sandwich dimers formation. The changes observed in the fluorescence spectra confirm these assumptions. The long-wave shift of maximum fluorescence band in comparison with monomeric emission is indicated, that fluorescence in LB film corresponds to a radiative transition from the lower excited level of plane dimers. Dye II molecules also participate in aggregation processes that leads to deformation of absorption and fluorescence spectrum in comparison with its ethanol solution spectrum. The ratio between the intensities of the short-wave and long-wave absorbance maxima of dye II is higher than that of dye I. The fluorescence spectra of dye II LB films consist of one band, which slightly broadened, but with similar shape and maximum position compared to ethanol solution. LB films with addition of stearic acid (SA) molecules have been received for the purpose of modification of films structure. The polymer concentration in three-component monolayers was a constant (33 mol%), and a dye and SA ratio changed in following proportions: 11:55, 22:44, 33:33 mol%. Study of phase states on a subphase surface has shown, that three-component monolayers are in more condensed state in comparison with two-component monolayers, that specifies in more compact molecules arrangement in a monolayer. It is observed two maxima in absorption spectra of dye I LB films: the most intensive corresponds to a monomeric band, short-wave, shown in the form of a shoulder, denotes the presence of «sandwich» type dimers in the film. There are two maxima in the dye I fluorescence spectra – monomeric (λmax=585 nm) and dimeric (λmax=610 nm), which are clearly defined in comparison with two-component films. The intensity of monomeric band is decrease with increasing of SA concentration in LB film, and the long-wave dimer band becomes more intensive. Presence of monomers and aggregates for three-component films of dye II also is characteristic.

59

NEW BLUE- AND GREEN-LIGHT-EMITTING ELECTROLUMINESCENT POLYFLUORENES WITH 7,8,10-TRIARYLFLUORINE AERIAL FRAGMENTS IN BACKBONE

M.L. Keshtov1, D.A. Lypenko2, S.I. Pozin2, E.I. Maltsev2

1 - A.N. Nesmyanov Institute of Organoelement Compounds RAS, Moscow, Russia

2 - A.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia keshtov@ineos.ac.ru

Over the last few years, efforts were focused on the manufacture of emitting and blocking layers based on new polymers with efficient conductivity and photoluminescence to be used in electroluminescent structures. In order to form desired electroluminescent layers we had to prepare blue-emitting polymers soluble in chloroform. At the initial stage, an attempt at synthesizing polymers with improved electron-hole conductivity and liquid-crystalline structure succeeded in obtaining new fluorine-based copolymer that revealed high solubility in non-polar solvents and film-forming properties:

H17C8 C8H17

O

O

ArH17C8 C8H17

Ar

n

+

IVV(a-d)

где Ar = (b) (c)H17C8 C8H17

(a) (d), , ,

CO-2

Tg values of the polymers varied within 280 – 310° С depending on the chemical structure of monomers. Thermogravimetric analysis showed high thermal stability under argon atmosphere as well as in air. Their weight loss did not exceed 10% within 570-580°С. Blue fluorescence spectra had maxima in the range 340 – 420 nm. The polymers exhibited liquid crystalline properties that made them suitable media for the formation of oriented J-aggregate structures. A start has been made on the investigations of polymer/nanocomposite and polymer/J-aggregates interface properties with J-aggregates aligned normally to the interface. In summary, by finely optimization the contents of various aromatic fragments, we successfully prepared a series of blue-light-emitting copolymers that are particularly well suited as active light-emitting polymer media to form oriented J-aggregate structures. This work was supported by the International Scientific and Technical Center (project no. 3718).

60

[C60(CN)5]-: A REMARKABLY STABLE [60]FULLERENE ANION

E.A. Khakina1, P.A. Troshin1, D.V. Konarev1, A.S. Peregudov2, I.V. Soulimenkov3, S.M. Peregudova2, R.N. Lyubovskaya1

1 - IPCP RAS

2 - INEOS RAS 3 - Institute for Energy Problems of Chemical Physics RAS (Branch)

eka57671232@yandex.ru

Ionic salts incorporating anions formed from pristine C60 showed exciting electrical (conductivity and even superconductivity) and magnetic (ferromagnetism) properties. However, these systems are hardly applicable as materials since they undergo immediate degradation in air reacting with oxygen and moisture. To overcome this problem, some chemical derivatization should be carried out with the fullerene sphere to enhance its electron accepting ability and thus make possible formation of air-stable fullerene anions. Here we will report a facile conversion of chlorofullerene C60Cl6 to the first air-stable fullerene anion [C60(CN)5]

-.

The obtained spectral data proved unambiguously that [C60(CN)5]- ion indeed has the highly

symmetrical C5V structure. Strong field-effect of five electron withdrawing CN groups stabilizes additionally the negative charge delocalized in the cyclopentadienyl ring. Owing to such great stabilization, the [C60(CN)5]

- anion demonstrated a remarkable stability. Thus, the anion was not protonated even by so strong inorganic acid as DCl and the parent acid C60(CN)5H was not formed. This finding opens wide opportunities for design of numerous air-stable salts incorporating [C60(CN)5]

- anions. Such ionic compounds might find many useful material science applications. Moreover, new members of the family of stable cyanofullerene anions might become available in the nearest feature. In particular, we have already observed by ESI MS air-stable fullerene dianions [C60(CN)8(OH)2]

2-, [C60(CN)9(OH)]2- and [C60(CN)10]2- and work now on their isolation

and spectroscopic characterisation.

61

SPECTRAL AND SENSING PROPERTIES OF 9-DTAA DYE IN POLYMER MATRICES

A.A. Khlebunov, P.V. Komarov, D.S. Ionov, A.V. Koshkin,

V.A. Sazhnikov, M.V. Alfimov

Photochemistry Center RAS, Moscow, Russia sazhnikov@yandex.ru

Molecules with intramolecular charge-transfer are the main elements of the most part of organic photonics devices [1]. The compounds with light emission during recombination of charge-transfer existed states are used in organic light-emitting diodes, fluorescent solar concentrators [2] and fluorescent sensor materials. Recent investigation [3] has shown that 2,7-dimethyl-9-ditolylaminoacridine (9-DTAA) molecule exhibits pronounced solvatofluorochromic properties related to charge-transfer character of S1 state. This assumption have been confirmed by quantum-chemical calculations using INDO/S with spectroscopic parametrization [4]. In this work, the fluorescence spectra of 9-DTAA in two polymer matrices were studied. The first type of the matrices are thin polystyrene (PS) and polymethylmethacrilate (PMMA) films obtained with spin-coating. The second type of the matrices are silicon dioxide microspheres with 6 nm average pore size and 10 µm average diameter, which were modified with various functional groups (Diaspher).

Figure 1 – a) Fluorescence of 9-DTAA in different matrices 1 – Diaspher-Phenyl, 2 – PS, 3 - Diaspher-Diol, 4 – PMMA, 5 - Diaspher-OH, 6 - Diaspher-C18; b) Electron micrograph of a sensor layer, c) Response of a sensor layer (Diaspher-OH with immobilized 9-DTAA) upon exposure to ethanol vapors. The 9-DTAA was used as a molecular indicator for preparation of sensing layers based on the silicon dioxide microparticles. A typical sensor layer consists of substrate, binding substance, microparticles and indicator molecules. A cover glass was used as the substrate, an acrylic latex A70 was used as the binding substance. An electron micrograph of a sensor layer is shown in figure 1b. The emission intensity responses of sensor layers to the presence of vapors of ammonia, acetone, ethanol were obtained. These analytes are known to be important for medical applications. The response of a sensing layer based on 9-DTAA and microparticles with functional OH groups on the surface is shown in figure 1c. 1. E.L. Aleksandrova. Phys. Тech. Semicond. – 2004. – V. 38. . 10. P. 1153-1194.(In Russian) 2. V. Petrova-Koch, R. Hezel, R. Goetzberger. High efficient low-cost photovoltaics. Springer

2008. P. 159-176. 3. V.А. Sazhnikov, А.А. Khlebunov, М.V. Аlfimov. High Energ. Chem. – V.41. . 1. P. 25-28. 4. L.G. Samsonovа et al. High Energ. Chem. – V.43. . 2. P. 105-115.

1 b

62

POLYSUBSTITUTED DERIVATIVES OF PALLADIUM TETRAPHENY L TETRABENZOPORPHYRIN. SYNTHESIS AND PROPERTIES

A.V. Khoroshutin, D.E. Chumakov, B.M. Uzhinov, A.V. Anisimov

Department of Chemistry, Moscow State University, Moscow, Russia

khorosh@petrol.chem.msu.ru

Earlier we found that palladium tetraphenyltetrabenzoporphyrin 1 can be regioselectively brominated to benzo-rings [1],. Further studies of this reaction allowed us to synthesize both octabromide 2 [2], and monobromide 3.

NN

NN

NN

NN

Br Br

Br

Br

BrBr

Br

BrPd Pd

1 2

NN

NN Pd

Br

3

Palladium catalyzed cross-coupling reactions yielded mono- and octasubstituted acryl and phenyl derivatives.

NN

NN

R R

R

R

RR

R

RPd

R = CH=CHCOOEt

R = Ph45

NN

NN

RPd

R = CH=CHCOOEt

R = Ph67

UV-Vis and phosphorescence spectra have been studied for synthesized compounds. Both phenyl and acryl substitution have been found to lower energy shift electronic absorption spectra bands, the same have been found for phosphorescence. Phosphorescence quantun yields have been measured relative to 1. This study was supported by RFBR (Grant No.09-03-00550-а) References 1. Khoroshutin A. V., Vinogradov S. A., Wilson D. F. // ACS National Meeting. 1998. P. 49.

Dallas, TX, US. 2. Khoroshutin A. V., Chumakov D. E., Kobrakov K. E., Anisimov A. V. // Russ. J. Gen. Chem.

- 2007. - V. 77. - No. 11. -P. 1959-1964.

63

STRUCTURE AND NONLINEAR OPTICAL PROPERTIES OF BILAY ER CELLS WITH ORGANIC AND SEMICONDUCTOR NANOFILMS

COVERED BY LYOTROPIC MESOPHASE OF METAL ALKANOATES

G. Klimusheva1, Yu. Garbovskiy1, S. Bugaychuk1, A. Tolochko1, T. Mirnaya2

1 - Institute of Physics NASU, Kiev, Ukraine 2 - Institute of General and Inorganic Chemistry NASU, Kiev, Ukraine

klimush@iop.kiev.ua

Bilayer cells with organic and semiconductor nanofilms covered by lyotropic mesophase of metal alkanoates may have great interest for applications in nanophotonics and nano-opto-electronics. In the present work the structure of lyotropic mesophase of metal alkanoates is investigated by X-ray diffraction technique, as well as bilayer cells with different nanofilms are studied for their spectral and nonlinear-optical properties. To prepare bilayer cells of the first kind (i) we use nanofilms of ionic symmetric polymethine dyes (both cation and anion types) covered by lyotropic liquid crystal (LLC) phase of the potassium caproate in a water solution (in the weight proportion 1:1). In the cells “dye nanofilm – LLC layer” one records thin dynamical gratings by the interference field formed during two-wave mixing of laser pulses with nanosecond durations (the second harmonic of Nd:YAG laser). The observed effect is differed drastically from the case when the only dye nanofilm is present. In the later case the recording of permanent relief holographic gratings occurs under the same experimental conditions because of heating and evaporation of dye molecules on the interference maximums of the laser field. The use of the LLC layer provides the dynamical character of the grating recording in the bilayer cells when the LLC moisten the dye film and a closed contact between the film and the LLC is created. This contact provides an effective heat diversion of the energy absorbed by the dye film to the LLC layer that prevents heating and evaporating of the dye film. We define that the cubic resonance nonlinearity is the main mechanism of the dynamical grating recording in the bilayer cells (i). Nanofilms formed by deposition of different semiconductors on a support may be covered by LLC of metal alkanoates as well. We prepare the bilayer cells based on CdSe nanofilm covered by the potassium caprilate LLC (the cells of the second kind (ii)). We investigate spectral and nonlinear optical properties of such cells.

64

INVESTIGATION OF DEGRADATION PROCESSES IN ORGANIC LIGHT-EMITTING DEVICES

B.A. Kondracki, N.N. Usov, A.U. Kruchinin

JSC CRI Cyclone, Moscow, Russia

Usov-nn@yandex.ru

Organic light-emitting diodes (OLED), based on the emission of light from thin films of organic materials in the passage of electric current through them, draw from the late 80-ies of the last century increasing attention [1, 2]. The nanoscale structure of organic layers, that is a core of these devices, is subjected to environment hazards. Degradation of the basic parameters of these devices in the first phase of development based on empirical knowledge, and had descriptive character. Successes in obtaining a stable OLED, needed to correct study of degradation processes, were associated primarily with the protection methods active areas of devices and encapsulation methods. Application of device construction, which includes a glass (or metal) cover with adsorbent, allowed properly proceed to study the mechanisms of degradation depending on the devices operation. Experimentally it was determinated [3], that the temporal dependence of the brightness of OLED radiation can be described by the expression:

L = L0·exp(-α·tβ), (1) where, α(t), β(t) – curve fitting parameters for the aging of the brightness of the radiation. Physically, the parameter α depends on the applied voltage and operation modes (continuous or pulse), β-reflects own material degradation due to electrochemical reactions at the boundary of organic layers, photodegradation and degradation of anode, the curves α (t), β (t) depend on color of light. In engineering calculations more convenient to use the dependence of the radiation brightness OLED (L) from the current running through it (I): This dependence is well approximated by the formula:

L=k·I. (2) The linearity of this characteristic is confirmed in several experimental works [4]. In the design of OLED-devices is important to know, how the coefficient k is changed with time in order to be able to design a scheme of correction that increases the service life of the device. We was conducted experimental studies of degradation processes in encapsulated OLED structures of different color light. The preparation of layers of OLED structures carried out by vacuum thermal evaporation at pressures less than 10-6 Torr. The thickness of layers varied from 5 to 100 nm. The shadow mask used for the formation of the topology layers. Evaporation of all layers and encapsulation of OLED structures was carried out in a on single technological cycle in sealed boxes (MBraun), in which the contents of moisture vapor and oxygen in an inert environment do not exceed 1 ppm. There are discussed the characteristics of degradation time for the brightness of the various structures of different color, the changes in the coefficient k and the sources of OLED degradation. Literature 1. V. Belyaev, New display technologies and their applications, Electronic Components, 2003, 3, p. 26.

2. A.V. Samarin, OLED Displays: from myths to reality, Modern Electronics, 2006, 1, p. 28. 3. H. Cloarec, D. Vaufrey, T. Mohammad - Brahim et al. Proceedings of the 27th International

Display Research Conference, Moscow, 2007, p. 215-218. 4. G. Levy, W. Evans, J. Ebner, P. Farrel, M. Hufford, B. Allison, D. Wheeler, H. Lin,. O.

Prache, E. Naviasky, IEEE Journal of Solid-State Circuits, vol. 37, 12, p. 1886.

65

DERIVATIVES OF DIVINYLBENZOXAZOLYLBIPHENYL: NEW ELECTROLUMINESCENT MATERIALS

T.N. Kopylova1, A.V. Kukhto2, I.N. Kolesnik2, I.N. Kukhto2, N.A. Galinovski2,

K.M. Degtyarenko2, N.S. Eremina2, R.M. Gadirov1

1 - Tomsk State University, Tomsk, Russia 2 - Institute of Physics NAS of Belarus, Minsk, Belarus

kopylova@phys.tsu.ru

Among a wide group of conjugate organic compounds, some biphenyl short-chain analogs of polyphenylenevinylene derivatives demonstrate good stability and photoluminescent properties. Therefore, a number of such compounds have been synthesized and the optical and electroluminescent properties necessary for producing stable light-emitting structures have been investigated. We investigated the compounds whose structural formulas are presented below.

N

O

O

N

I

O

N

N

O

SO O II

An electroluminescent cell was created as follows. On a glass substrate with a conducting indium and tin oxide (ITO) layer (In2O3⋅SnO2 with a thickness of 100 nm, resistance of ∼100 Ω/m, and transparency of 95–98% in the visible range), a polythiophene (PEDOT) layer and a layer of the corresponding examined substance incorporated into a polymeric polyvinylcarbazole matrix (with a thickness of about 80 nm) were subsequently centrifugalized. Then a 2 × 3 mm calcium and magnesium alloy layer with a thickness of 150 nm was deposited by evaporation in vacuum using a VUP-5 facility. Before centrifugation and deposition of layers, the substrate with the conducting layer was carefully washed out in organic solvents in an ultrasonic bath, and after drying it was treated for 30 min in oxygen plasma. A negative potential was connected to the metal electrode, and a positive potential was connected to the transparent electrode. The current-voltage and voltage-brightness characteristics were measured using a specially developed complex, and the electroluminescence was registered using an Avantes CCD spectrometer. The emission spectra of organic films were investigated using a Carry Eclipse spectrofluorimeter. The threshold electroluminescence voltage for both samples was smaller than 5–6 V, though it depended on the layer thickness. When the voltage increased to 8.5 V, the luminescence intensity for sample I saturated, though the current did not. For compound II, we observed no saturation when the voltage changed within these limits. The saturation is most likely caused by the recrystallization process observed for the examined compounds and unperceptible by the naked eye. The recrystallization changing the film morphology was observed even at room temperature together with the absorption and fluorescence spectra. In the process of OLED operation, the temperature increased, and the recrystallization was amplified. The luminescence brightness was sufficiently high. The electroluminescence spectra for both compounds were similar. They were observed in the same wavelength range as the photoluminescence spectra; however, their maxima were significantly shifted toward longer wavelengths. From the short-wavelength side of this spectrum, an additional shoulder was observed caused most likely by the contribution of polyvinylcarbazole luminescence. High currents running through the OLED demonstrate good electron transport properties of the given compounds.

66

MAGNETIC FIELD EFFECT ON THE POLYARYLENEPHTHALIDES ELECTROLUMINESCENCE

A.A. Kovalev1, V.A. Antipin2, A.N. Lachinov1, S.N. Salazkin3, V.P. Kazakov2

1 - Institute of Physics of Molecules and Crystals URC RAS, Ufa, Russia

2 - Institute of Organic Chemistry URC RAS, Ufa, Russia 3 - Institute of Elementoorganic Chemistry RAS, Moscow, Russia

lachinov@anrb.ru

Electroluminescence (EL) is a recombination process. Its probability depends on different quantum parameters of a multilayer structure. One of these parameters is spin of the relaxing electron. Spin orientation of the injected electron can be changed by the external magnetic field. In this work EL’s parameters subject to the influence of the external magnetic field were investigated. The results of this experiment are presented. The EL was measured in the Al/polymer/ITO multilayer structure (ITO is mixture of indium oxide and tin oxide). The non-conjugated polymer was used from the polyarylenephthalide class, namely, statistical copolymer polyaryleneetherketones (co-PAEK). Polymer film (560 nm pf thickness) was deposited on the surface of the ITO layer. Used solution for polymer was cyclohexanone. Aluminium electrode was deposited on the polymer film by vacuum evaporated technique. Measurement were carried out at normal atmosphere and room temperature. Early it was shown that co-PAEK demonstrated satisfactory EL with spectrum in visible region.

Fig. 1. EL spectrums outside (solid line) and inside (dotted line) of the magnetic field.

The influence of the magnetic field on the EL spectrums is shown in fig. 1. Spectral shape changes inessential. But the EL intensity considerably reduces in the magnetic field presence. Mechanism of the observed effect and features of the magnetic field influence are discussed in the report.

Длина волны (нм)

200 300 400 500 600 700 800 900

Инте

нсив

ность (

отн.

ед.)

0

1

2

3

4

5

6

Без магнитного поля

В магнитном поле

Magnet field Off

Wavelength, nm

Magnet field On

Ele

ctro

lum

ines

cenc

e, a

rb.u

n

67

EXIPLEX ELECTROLUMINESCENCE SPECTRA IN THE ORGANIC LIGHT-EMITTING DIODES

BASED ON SULPHANYLAMINO ZINC COMPLEXES

S.S. Krasnikova, M.G. Kaplunov, I.K. Yakushchenko

Institute of Problems of Chemical Physics RAS, Russia skras@cat.icp.ac.ru

It is well known that the electroluminescence (EL) spectra of the most of organic materials are similar to their photoluminescence (PL) spectra. This is due to the fact that the same energy levels are involved in the EL and PL processes. For some of our devices an opposite situation is observed: the EL spectra significantly differ from the PL spectra of the organic components. The shape of the EL spectra depends on the composition of the hole-transporting layer. We have measured the EL spectra of the organic light-emitting diodes based on the new zinc complexes with sulpanylamino-substituted quinolines and 2-phenyl-benzazoles [1]. The EL was observed for the layered structures containing the transparent anode of indium-tin oxide (ITO), organic hole-transporting layer, luminescent layer of one of the studied complexes and the metallic cathode. In the EL spectra of the devices, the component band with the maximum at about 450 nm is observed which may be attributed to the electronic transitions intrinsic for the zinc complex. This component coincides with the PL spectrum of the sample. Besides this intrinsic band, the additional wide band is observed in the region of 500-650 nm. While PL is excited in the bulk of the film, EL arises at the interface of the hole-transporting and the electron-transporting layers. The additional long-waved EL band may arise due to an intramolecular interaction at the interface probably as a consequence of the formation of exiplex between molecules of hole-transporting and luminescent materials. The relation of intensities of the intrinsic and exiplex bands depends on the material of the hole-transporting layer. Due to large widths of the EL spectra from blue to red spectral region, the light from some devices is nearly white. The CIE color coordinates of one of the devices are x=0.30, y=0.34 which is close to pure white (x=0.33, y=0.33). 1. M. G. Kaplunov, I. K. Yakushchenko, S. S. Krasnikova, A. P. Pivovarov. Electroluminescent

Devices Based on Novel Zinc Complexes of Sulphonylamino Substituted Heterocycles Mol. Cryst. Liq. Cryst., Vol. 497, pp. 211–217, 2008

68

INFLUENCE OF ETHANOL VAPORS ON SPECTRAL BEHAVIOR OF NILE RED IN ORGANIC-SILICATE MATRIX

D.I. Lupikov, T.G. Movchan

A.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia

movchan@phyche.ac.ru

One of the prospective ways of sensor technologies development is making of optical chemical sensors. Through optical characteristics change of sensor material, composed of molecule-indicator, situated on solid matrix, it can be judged about the analyte presence. Fluorescence is more sensitive and informative enough optical characteristic. Organic polymers, providing high fluorescence intensity and preventing the effects of dye protonation, which influence decreases dye emissivity, are often used in chemical sensor structures. In paper [1] strong hydrogen bond polymer was used for matrix preparation of fluorescent sensor. The effect of dye protonation in polymer matrix led to increase of fluorescence intensity in analyte vapors. Pore structure in combination with optical clarity and mechanical strength makes silicate sol-gel matrix in aggregate with introduced at room temperature organic modifiers an attractive material for wide application in photonics, including as optical sensor [2]. Protonation effects in organic-silicate sol-gel systems, produced with silanol groups Si–OH of quartz glass and/or alcohol groups can cause increase of fluorescence intensity in analyte vapors, as in the case of acidic polymer [1]. Investigation of hybrid sol-gel matrix, prepared by synthesis of tetraethoxysilane (TEOS) and 3-glycidoxypropyltrimethoxysilane (GLYMO) with subsequent introduction of Nile Red (NR), concerning the effect of ethyl alcohol vapors by fluorescence analysis was the purpose of this work. Tenfold increase of dye fluorescence intensity was found out in the experiments with samples as films of 40TEOS:60GLYMO composition by way of response to ethanol vapors. Fluorescence intensity of dye decreased after film heat treatment, taken on a value similar to original state. The effect of fluorescence “building-up” of NR, situated on solid matrix, under ethyl alcohol vapors exposure can be explained by change of dye molecules environment. Apparently, sorption of ethanol vapors was carried out in competition of dye NR and ethanol to interaction with sides of hybrid matrix. As a result of dye displacement from hydrogen bond matrix sites its local environment and so fluorescent properties changed. Low-polarity environment, in which dye has configuration with high fluorescent properties, was created by glycidoxypropyl groups of GLYMO [3]. As a result of heat treatment removal of alcohol vapors occurred, dye molecules reverted to original environment that led to decrease of fluorescence intensity. Literature. [1] Levitsky I., Krivosclykov S.G., Grate J. W. //Anal. Chem. 2001. B. 73. P. 3441 [2] Schmidt H., Scholze H. and Tünker G. // J. Non-Crystall. Solids. 1986. V. 80. P. 557 [3] Ferrer M.L., del Monte F. // J. Phys. Chem. B. 2005. V. 109. P. 80

69

EFFICIENT MULTILAYER ELECTROLUMINESCENT ORGANIC STRUCTURES BASED ON IRIDIUM(III) COMPLEX

D.A. Lypenko, A.V. Dmitriev, E.I. Maltsev, A.V. Vannikov

A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, RAS, Moscow, Russia

lypenko@rambler.ru

In phosphorescent compounds, strong spin-orbit coupling leads to efficient intersystem crossing of the singlet excited states to the triplet manifold, and also mixes the singlet and triplet excited states, removing the spin-forbidden nature of the radiation transition of the triplet state to the ground state. Various kinds of phosphorescent organic materials and many electroluminescent OLED structures based on these dyes have been tested. Here we report a highly efficient multilayer electroluminescent (EL) organic structure using the iridium(III) complex as a dopant in the emitting layer. Typical developed OLED structure with six functional organic layers (Fig.1) and its emission band (Fig.2) are given below.

0

0.5

1

350 450 550 650 750

Wavelength, nm

EL,

a.u

.

Fig.2

Fig.1 Device configuration we have developed was as follows ITO/Cooper (II) phthalocyanine/4,4′,4″-tris[2-naphthyl(phenyl)amino]triphenylamine/N,N’-diphenyl-N-N’bis(1-naphthylphenyl)-1,1’-biphenyl-4,4’-diamine/ bis(2-phenylpyridine) iridium(III) acetylacetonate : 3-(Biphenyl-4-yl)-4-phenyl-5-(4-tert- butylphenyl)-1,2,4- triazole /2,9-dimethyl-4,7diphenyl-1,10-phenanthroline/ 4,7-Diphenyl-1,10-phenanthroline/ LiF/ Sm(5%):Al/ Al. In conclusion, high efficiency (23 lm/W) and low turn-on voltage (3,5 V) using the complex as a phosphorescent dopant in the emitting layer have been demonstrated.

80 nm Al

5 nm Sm/Al

1 nm LiF

15 nm BPhen

6 nm BCP

25 nm Ir complex:TAZ

10 nm NPD

40 nm 2-TNATA

5 nm CuPc

ITO Glass substrate

70

DYNAMICS OF ABSORPTION AND LUMINESCENCE OF CdSe/ZnS QUANTUM DOTS IN THE PROCESS

OF AGGREGATION IN HYDROPHOBIC SOLUTIONS

V.G. Maslov, V.E. Adrianov, A.O. Orlova, A.V. Baranov, A.V. Fedorov

St.Petersburg State University of Information Technologies, Mechanics and Optics, Russia maslov04@bk.ru

Currently, one of the most important and rapidly developing areas of nanotechnology is the creation of ordered structures of nanoparticles, such as colloidal quantum dots (QDs). Depending on the number and composition of nanoparticles these structures could have the remarkable properties, in particular, the ability to accumulate the absorbed radiation and transform it, e.g. to change the parameters of QD luminescence spectra. In this regard, determining the conditions of spontaneous QD aggregate formation with such properties in solution is of special interest. In this work the dynamics of spontaneous aggregation of CdSe/ZnS QDs capped with Trioctylphosphine oxide (TOPO) with deficiency of TOPO on the QD surface has been investigated in hexane, carbon tetrachloride, and chloroform at low QD concentrations (about 5·10-7М). It was shown that the dynamics of spontaneous QD aggregate formation and their optical properties are primarily determined by the choice of solvent. So, in hexane the fast spontaneous aggregation accompanied with the significant decrease of luminescence of solution with the characteristic time of about 2.5 hours and subsequent precipitation of QDs aggregates were observed. The addition into the solvent of the TOPO access with the concentration of 3·10-4 prevents the spontaneous aggregation of nanocrystals and ensures the stability of the optical properties of the QD solutions during tens of hours. Completely different picture was observed in the TOPO deficient QDs in chloroform. It should be noted that this solvent, unlike hexane, could be coordinated on the surface of QD, replacing TOPO molecules. It was found that QDs in chloroform are initially in aggregated state. This is reflected in the significantly lower luminescence quantum yield (by two orders of value lower than in hexane), and in larger halfwidth of QD luminescence band (FWHM is 32-35 nm compared to 26 nm in hexane). Investigation of the evolution of absorption and luminescence spectra of the QD solution showed that the rapid precipitation of QD aggregates from the solution took place. At the same time, the remaining in the solution QD aggregates underwent significant changes. This was evidenced by the broadening of absorption spectrum characteristic for larger aggregates as well as by some abnormal changes in luminescence spectrum of the solutions: an increase of luminescence intensity and the hypsochromic shift of luminescence band. Such an evolution of the spectra may be an indication of the penetration of solvent molecules inside the QD aggregates, leading to a gradual loosening and disaggregation. This suggests that in few dozen hours the formation of new type QD aggregates in chloroform takes place with hypsochromically shifted luminescence band (520 nm compared with 530 nm in hexane) and with QD luminescence quantum yield, comparable with the quantum yield in hexane. The addition of TOPO in chloroform does not lead to stabilization of the solution. In carbon tetrachloride the QD solutions were stable within tens of hours. However some long-time changes of luminescence and absorption properties took place: considerable hypsochromic shift of both absorption and luminescence bands. These changes can be explained by the partial substitution of TOPO by the solvent molecules which like the chloroform molecules can coordinate to the QD surface.

71

QUENCHING OF ELECTRONICALLY EXCITED CARBAZOLE BY A STABLE IMIDAZOLIDINE RADICAL

A.G. Matveeva1, D.V. Stass1, V.V. Korolev1, V.F. Plyusnin1, V.A. Reznikov2

1 - Institute of Chemical Kinetics and Combustion, Novosibirsk State University, Russia

2 - Novosibirsk Institut of Organic Chemistry, Novosibirsk State University, Russia matveeva@kinetics.nsc.ru

The processes of intermolecular quenching of excited states of aromatic hydrocarbons by various free stable radicals are one of the rather well developed branches of molecular photochemistry. Much interest today is directed towards quenching in linked systems, where the quencher and the luminophore are parts of the same molecule. It has been demonstrated that in the studied linked systems the quenching proceeds via the mechanism of exchange-induced relaxation of the local excited state of the luminophore, while in free systems the entire range of classical quenching mechanisms can be observed. In this work as a part of the program on creating model radiation-induced three spin systems we synthesized a precursor system “carbazole CBZ – imidazolidine nitroxyl radical R•”, studied its photophysical properties, and compared it to free CBZ and R• in solution.

N

N

N

OФт (CBZ) = 0.36Фs (CBZ) = 0.38Фs,т (CBZ-R ) = ?

For the linked system CBZ-R• the relative decrease of quantum yield and fluorescence lifetime of the local singlet-excited state was estimated to by about 103. No locally excited triplet state of the carbazole moiety was registered at times 50 ns and longer. For the chemically non-bound CBZ and R• the rate constants of intermolecular quenching of singlet and triplet excited states of carbazole in acetonitrile were found to be (1.4 ± 0.1)×1010 M-1sec-1 and (1.5±0.2)×109 M-1sec-1, respectively. Based on the results of our experiments we suggest exchange-induced energy transfer and exchange-induced acceleration of local relaxation as the most plausible quenching mechanisms. We shall also discuss the processes of Forster energy transfer, electron transfer, and accelerated intersystem crossing for this system. Work supported by RFBR (projects 08-03-00313, 07-02-91016-AF), INTAS (project 05-10000008-80) and the Program of the Division for Chemistry and Material Science RAS for 2009 (project 5.1.6.).

72

OPTICAL FORMATION OF GRADED-INDEX WAVEGUIDE STRUCTURES IN PHOTOPOLYMERIZABLE COMPOSITES

S.N. Mensov, Yu.V. Polushtaytsev

G.A. Rasuvayev Institute of Organometallic Chemistry RAS, Nizhny Novgorod, Russia

mensov@iomc.ras.ru

Nowadays, photopolymerization methods are commonly used to produce optically homogeneous materials and they allow to shape the surface of an optical element at one time. Polyfunctional monomers (as a rule, di(meth)acrylates) are employed for this processes. Photopolymerization of them results in polymer formation with nano-sized reticular structure which doesn’t scatter optical radiation. However, graded-index materials with preset distribution of the refraction parameter are more effective for optics. Refraction parameter profile adjusting makes it possible to improve technical features of waveguide structures considerably and to provide optical flow separation and joining. Polymer net structure controlling allow to create stable graded-index optical materials by light directly if additional non-polymerizable compounds (NC) differing in refraction parameter are used in the mixture of photopolymerizable composite (PPC). Among the neutral compounds are molecular and ionic solvents. The process of composite compounds redistribution during polymerization depends on the monomer conversion rate, determined by actinic radiation intensity. Realization of nonlinear wave processes in such mediums gives an opportunity for optical synthesis of the elements for fiber optics [1], formed directly by light but proof against actinic radiation. Low-energy mechanisms of interaction with irradiation are typical for PPC. However, realization of nonlinear wave processes require low-absorbing composite with spectral sensitivity out of the monomer absorption band. O-quinones meet this requirements and they initiate photopolymerization of oligomers upon the acting of the visible radiation. In this paper we consider nonlinear wave processes of waveguide structures optical formation in transparent PPC with NC. A diffusion model for the process of the PPC compounds redistribution during the photopolymerization by inhomogeneous irradiation has been formulated. Conditions of stable polymeric waveguide formation by laser irradiation with essential diffractive divergence have been determined, in particular, for the radiation propagating from the ends of standard quartz fibers. Stable polymeric waveguide structures compatible with standard quartz fibers have been synthesized in the PPC based on the mixture of methanol and oligomer OCM-2 with quinone photoinitiating complex by the low-energy laser irradiation (the power was less than 10 mW). This work was supported by RFBR (grant 08-03-12090, 08-03-97055 and 09-03-00668. [1] Mensov S.N., Polushtaytsev Yu.V. Optical Connecting of Fibers by Laser Beams

Propagating From the Fibers Edges // Advances in Optical Technologies, 2008, vol.2008, Article ID 719632, doi:10.1155/2008/719632.

Fig.1 – Polymeric channel synthesized by light between the fibers CS-980 and SMF-28.

73

NOVEL PHOTOCHROMIC SPIROPYRAN CATIONS WITH A PYRIDINIUM MOIETY IN THE ALIPHATIC SIDE CHAIN

A.V. Metelitsa1, S.O. Besugliy2, N.A. Voloshin2, E.V. Soloveva1, V.I. Minkin1

1 - Institute of Physical and Organic Chemistry, Southern Federal University,

Rostov-on-Don, Russia 2 - Southern SC RAS, Rostov-on-Don, Russia

met@ipoc.rsu.ru

Salts of spiropyrans (SP+X

-) and spirooxazines (SO

+X

-) hold promise for the development of hybrid

polyfunctional materials, combining photochromic and magnetic properties in a single crystal lattice, in which the spiropyran or spirooxazine cations have photochromic properties. In a continuation of these studies, a series of cationic spiropyrans (SPP) 1-4 containing a pyridinium fragment in the aliphatic side chain have been synthesized.

O

MeMe

N

Me

R

R

N

1

2

X_

+

1

2

X_

+

+_

hν, ∆

hν, ∆N

R

O

MeMe

N

Me

R

А В

1 R1 = Cl, R2 = NO2, X = Cl; 2 R1 = OMe, R2 = NO2, X = Cl; 3 R1 = R2 = H, X = Br; 4 R1 = Cl, R2 = H, X = Br

The electronic absorption spectra of the cyclic isomers of spiropyrans 1-4 in acetonitrile show long-wavelength bands at 290-345 nm with molar extinction coefficients at the maxima 3480-8180 mol

-

1·dm3·cm

-1 corresponding to an S0→S1

transition and stronger bands with maxima at 245-259 nm and molar extinction coefficient 16210-24190 mol

-1·dm3·cm

-1 for the S0→S2

transition. Irradiation of solutions of spiropyrans 1-4 in acetonitrile by UV light at the absorption bands of the cyclic isomers leads to coloration related to clevage of a C–O bond and subsequent cis-trans isomerization and the formation of a colored metastable product B. The maxima of the long-wavelength bands of the acyclic merocyanine isomers B of spiropyrans 1-4 are in the range of 540-586 nm. The merocyanine forms of SPP 1 and 2 demonstrate fluorescence at 293 K. The fluorescence band maxima are in the range of 618-625 nm and the fluorescence excitation bands are in good agreement with the long-wavelength absorption bands of merocyanine forms B. Thermal relaxation processes В→А are observed after the termination of UV-irradiation. Generally, the introduction of a quaternized pyridine fragment into the benzopyran part of the spiropyran molecule leads to a decrease in the rate of the thermal recyclization by three orders of magnitude. The photochemical channel for В→А recyclization was found under the excitation of the merocyanine forms of compound 1 and 2 to both the S1 and S2. By contrast, upon irradiation in the long-wavelength absorption bands of the merocyanine isomers of SPP 3 and 4 an increase in the rate of bleaching for their pre-colored solutions could not be detected against the background of the thermal relaxation. This work was financially supported by Russian Foundation for Basic Research (Project No. 09-03-00813) and by the Presidium of the Russian Academy of Sciences (Development of Methods for the Preparation of Chemical Products and Development of New Materials, Program No. 18).

74

THEORETICAL STUDY OF ADSORPTION OF AN ACRIDINE DYE AND SIMPLE MOLECULES ON A SILICA SURFACE

R.F. Minibaev1, N.A. Zhuravlev2, A.A. Bagaturyants1, M.V. Alfimov1

1 - Photochemistry Center RAS, Russia

2 - Moscow Engineering Physics Institute, Russia minibaev@gmail.com

The study of the interaction of organic dyes with an inorganic substrate is an extremely important problem in modern organic nanophotonics. In particular, this problem arises in the development of new nanostructured materials for optical chemical sensors that can detect the presence of small amounts of impurities in the gas phase by the change in the spectral properties of the sensing material. The main functional element of such a material is an organic dye molecule adsorbed on a substrate. Silica nanoparticles are a common substrate for the hierarchical construction of nanostructured materials for optical chemical sensors. In this case, studying the adsorption of possible analytes and organic dyes on the silica surface can provide useful information about the structure and properties of the sensing material. There are few papers in which the interaction of organic molecules with the silica surface has been studied theoretically [1, 2]; however, no systematical theoretical investigation of the interaction of various molecules and, in particular, dye molecules with the silica surface has been published so far. In this work, the adsorption of a number of simple molecules and acridine (considered as a model of an acridine dye) is studied theoretically. The model of silica was constructed based on a model of quasi-amorphous silicon oxide the structure of which was obtained by classical molecular dynamics simulation. The silica structure was amorphized by heating at high temperature followed by cooling. Water, ammonia, acetone, and ethanol molecules were adsorbed on the obtained amorphized surface. The acridine molecule was considered as a model for an acridine dye molecule. The calculations of the adsorption of molecules were performed using the periodic slab approximation. Calculations were performed using density functional theory (DFT) with a generalized gradient approximation (GGA) for the exchange-correlation potential. The most favorable adsorption positions on the silica surface were found. The structures of the adsorption complexes were calculated, and the adsorption energies of the molecules considered in this work on the silica surface were found. The electronic structure calculations of bulk alpha-quartz, quasi-amorphous silica, and silica surfaces revealed changes in the electronic structure due to the adsorption of molecules. 1. Marco Nonella, Stefan Seeger // ChemPhysChem, vol. 9, pp. 414–421 (2008). 2. Albert Rimola, Mariona Sodupe, and Piero Ugliengo, J. Phys. Chem. C, 113, 5741–5750 (2009)

75

SPECTRAL BEHAVIOUR OF NILE RED IN ORGANIC-SILICATE SOL-GEL MATRI СES

T.G. Movchan1, D.I. Lupikov1, T.V. Khamova2, O.A. Shilova2

1 – A.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia

2 – I.V. Grebenshchikov Institute of Silicate Chemistry RAS, St.Petersburg, Russia Movchan@phyche.ac.ru

Last years interest to the sol-gel derived hybrid organic-inorganic materials has increased. The reactions of hydrolysis and polyfunctional condensation of silicon alkoxides are the base for sol-gel processing and allow to include in oxide or hybrid matrixes a wide number of organic and inorganic additives, which provide special ordered physical-chemical properties to synthesized materials optical ones. However molecule of some dyes does not display fluorescent properties in the protonized mediums created by silanol groups which are present in sol-gel systems on the basis of alkoxy silanes [1]. The revealed feature of epoxy groups in 3-glycidiloxypropyltrimetoxysilane (GLYMO) to reduce effect of protoning owing to formation by these groups of a protective barrier [1] has allowed to assume about an opportunity of use for these purposes of other epoxy combination. The present paper is devoted to research of influence of a weight ratio of the basic components of a hybrid matrix (E and S) as well as solvents remaining in its pores on spectral behavior of dye Nile Red (NR). Hybrid organic-inorganic materials (gels, xerogels and glasses) based on sol-gel systems obtained by copolymerization ingredients of silicate (S) - of tetraethoxysilane (TEOS) and of organic (E): a) 3-glycidoxypropyltrimethoxysilane (GLYMO); b) mixture (50/50) of epoxy resins (DEG-1 and ED-20) with the different proportions (rE/S): 0/100; 20/80; 30/70; 40/60; 50/50; 60/40; 70/30. Concentrations of NR in sols are 2.2 · 10-7 moles. Spectrums of fluorescence have been obtained using spectrometer Perkin-Elmer LS’-55. Influence of a ratio of inorganic and organic components of a hybrid matrix in which are distributed nanosized inclusions of dye on spectral behavior of NR (shift of a wave of fluorescent radiation, emission intensity) is revealed. Two maxima on spectrums of radiation occur. It is supposed that occurrence of two peaks of emission for hybrid materials is caused by formation of structure interpenetrating inorganic (S) and organic (E) networks, and each network has the specific parameters of radiation. Influence of solvents on behavior of NR in mediums of various polarities is considered. At reduction of the contents of solvents in poorly polar medium the spectrum of emission was moved aside shorter wavelengths (dark blue displacement) and, on the contrary, in polar medium its removal resulted to displacement of an emission spectrum in the long-wavelength side (red shift). The analysis of data of IR-spectroscopy has shown that not all epoxy groups become convertible in proton alcoholic groups. Owing to this a diminution of polarity of medium near to NR occurs. Literature. [1]. James W. Gilliland, Kazushige Yokojama,and Wai tak Yip. // J. Phys. Chem. B. 2005. V.

109. P.4816-4823.

76

NEW PHOTOCHROMIC ASYMMETRIC BISPIROPYRAN OF THE 2,3-DIHYDRO-4-OXO-NAPHTO[2,1-E]OXAZINE SERIE

E.L. Mukhanov1, B.S. Lukyanov1, I.V. Dorogan1, S.O. Besuglui2,

Yu.S. Alexeenko2, O.N. Ryashin1, V.V. Tkachev3

1 - Institute of Physical and Organic Chemistry, South Federal University, Rostov-on-Don, Russia

2 - Southern SC RAS, Rostov-on-Don, Russia 3 - Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia

lab811@ipoc.rsu.ru

Bispiropyrans – compounds contatining two spirocyclic fragments in the structure are objects of special interest for researchers. We have synthesized new asymmetric bispiropyran 1 containing two different spirocenters and consequently two asymmetrical carbon atoms.

N

OO

NO

OCH3

CH3CH3

CH3

1 Picture 1. Structure of bispiropyran 1 detected by X-Ray analysis

Data of the quantum-chemical computations proved that obtaining of several isomers takes place as a result of opening of both pyran cycles in the molecule 1. This result is the first affirmed example of the simultaneous break of two Cspiro – O bonds for bispiropyranic systems.

400 500 600 700 800

0,000

0,005

0,010

0,015

0,020

0,025

0,030

0,035D

λ, нм

-20 0 20 40 60 80 100 120 140 160 180 200-0,01

0,00

0,01

0,02

0,03

0,04

0,05

0,06

0,07

dark

abs

time / s

λ 613 nm λ 507 nmdark

irr Σ irr 436 irr 313

продук

т на

копл

ен ран

ее

Picture 2. Absorption spectra of the bispiropyran 1 toluene solution at t = 20 °С

Picture 3. Changes of the absorbance intensity at 613 nm and 507 nm on the different experiment stages for the

bispiropyran 1 toluene solution This work was financial supported by the program “Development of the scientific potential of the high school” (RNP 2.2.1.1.2348), CRDF and the Ministry of Education and Science of Russian Federation in the frame of Russian-American program “Basic research and high education” (BRHE) (RNP 2.2.2.2.3915, RNP2.2.2.3.16011, BP3C04, BP4M04), Grant of The President of Russian Federation NSh-363.2008.3. and Russian Foundation for Basic Research (grants 07-03-00234-a, 08-03-90029-Bel).

77

COPOLYMERS BASED ON CYCLOPENTADITHIOPHENE FOR ORGANIC PHOTOVOLTAICS

E.N. Myshkovskaya1, S.A. Ponomarenko1, P.A. Troshin2,

S.D. Susarova2, S.D. Babenko3, N.M. Surin1, A.M. Muzafarov1

1 - Institute of Synthetic Polymeric Materials RAS, Moscow, Russia 2 - Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia

3 - Branch Institute of Energy Problems of Chemical Physics RAS, Chernogolovka, Russia mafox@inbox.ru

In recent years organic semiconducting polymers are the subject of intensive research because of high potential of their application in new generations of optoelectronic devices such as photovoltaic cells, light-emitting diodes, thin-layer transistors, etc. Among these polymers of particular interest are copolymers based on cyclopentadithiophene and its derivatives due to high solubility, low band gap and good transport properties of such materials. This paper presents synthesis of new copolymers of 4,4-dialkylcyclopenta[2,1-b:3,4b’]dithiophene with 9,9-dialkylfluorene (1) and 4,4-dialkylcyclopenta[2,1-b:3,4b’]dithiophene with spiro[4H-cyclopenta [2,1-b:3,4b’]dithiophene-4,2'-[1,3]dioxolane (2) (Fig. 1). For their preparation, we have improved some methods of synthesis of the monomeric precursors, as well as suggested a new synthetic way for the monomer based on 1,3-dioxolane derivative of the cyclopentadithiophene. Purity and molecular structure of the monomers and precursors for their obtaining was proved by NMR, mass spectroscopy and elemental analysis. Copolymers were prepared by the Suzuki reaction from the corresponding dihalogen and diorganoboron derivatives.

SS

RR

* RR

*n

R = -Oct, EtHex

OO

SS

SS

R R

* *n

1 2

Fig.1. Structural formulas of the copolymers obtained

Study of the optical properties of the copolymers obtained showed that copolymers 1 possess the strong absorption of light in the region from 400 to 500 nm, showing significant photoluminescence in the solution (quantum yield of 34% - 47%). The absorption of copolymers 2 is shifted to the red region on 60-70 nm as compared to copolymers 1, but they have rather weak luminescence. Measurement of the transport properties of diodes, prepared from the copolymers obtained, showed the hole mobility, reaching 10-3 см2/V.s и 10-4 см2/V.s for copolymers 1 and 2, respectively. Efficiency of the photovoltaic cells made on the basis of the nanocomposites of the copolymers with the fullerene derivative C60 (PCBM) was 0.36 - 0.53%. This work was supported by the Federal Agency for Science and Innovations (State Contract 02.513.11.3382).

78

MEAN FORCE POTENTIALS FOR ION PAIRS IN A BINARY SOLVENT MIXTURE

A.V. Odinokov1, M.V. Basilevsky1, E.A. Nikitina2, N.Kh. Petrov1, M.V. Alfimov1

1 - Photochemistry Center RAS, Moscow, Russia

2 - Institute of Applied Mechanics RAS, Moscow, Russia ale.odinokov@gmail.com

Mean force potentials (MFP) are calculated for two model symmetric ion pairs in the benzene/dimethylsulfoxide (DMSO) mixtures. The electrostatic part of the interaction free energy was found in MD simulations, which accounted for a separate treatment of fast electronic and slow nuclear components of the solvent polarization in terms of the recently developed methodology. Alternative computations of the electrostatic free energy in terms of the continuum solvent model are performed and compared with the molecular level simulation. The composition of the solvent mixture is determined as the average molecular fraction of DMSO, denoted as x. Change of x in the range 0<x<0.1 generates the variation of the MFP. The potentials treated as a function of inter-ion separation vary from deep wells, corresponding to contact ion pairs (x=0, pure benzene) to simple-shaped monotonously changing repulsive curves with flat minima; they are determined asymptotically by the dielectrically screened electrostatic interaction (x>0.5). The latter state of the solution system is associated with solvent-separated ion pairs. Intermediate composition range (x=0.1-0.2) is characterized by strong fluctuations of MFPs caused by the fluctuations in the composition of the ion pair solvation shell. The present work was performed with the financial support of RFBR grant 07-03-00479-a

79

STUDY OF A POLYMER MATRIX INFLUENCE ON PHOTOCHROMIS M OF SPIROPIRANES, INSERTED BY DIFFUSION FROM SOLUTIO NS

V.A. Optov1, A.O. Ait2, V.A. Barachevsky2, A.A. Berlin1, O.Yu. Sabsai1

1 - N.N. Semenov Institute of Chemical Physics RAS, Moscow, Russia

2 - Photochemistry Center RAS, Moscow, Russia ait@photonics.ru

Possibilities of obtaining the photochromic polymer composites by a method of diffusion insertion of photochromic molecules in different polymer matrices (low density polyethylene, polypropylene, polyurethane, polycarbonate, copolymers of ethylene with norbornene) were studied. As a model photochromic compound there was used a nitrosubstuted spirobensopyrane 1`,3`-dihydro-1`,3`,3`- trimethyl-6-nitro-8-methoxyspiro [2H-1-bensopyrane-2,2`-(2Н)-indole], which possesses reversible photodissociation of –C-O bond and the following cis- , trans-isomerisation. Comparative spectral-kinetic studies of the obtained samples were carried out, and there were determined the constants of photocolouring and spontaneous decolouration, as well as photodegradation. For the studied spiropyran there was made a quantitative evaluation of coefficients of the diffusion into polymer matrices from organic solvents (iso-butanol, benzene) and also quantitative evaluation was made for achieved concentrations of the spiropyran in a polymer volume. It was shown, that for all of the studied polymer samples there was observed a photochromic effect. Depending on the polymer nature, substantially changes the kinetics of the composite colouring at UV-irradiation and the following spontaneous decolouration.

80

FORMATION AND DISSOCIATION OF SEMICONDUCTOR QUANTUM DOT / DYE MOLECULE COMPLEXES

A.O. Orlova, Yu.A. Toporova, V.G. Maslov, A.V. Fedorov, A.V. Baranov

St.Petersburg State University of Information Technologies, Mechanics and Optics, Russia

a_v_baranov@yahoo.com

Last ten years semiconductor nanocrystals or quantum dots (QDs) are widely used in sensory systems for biological, medical and ecological applications [1]. It is expected that possibility to manage QD luminescent parameters by simple change of their size together with high photoluminescence QY and high photostability of QDs [2] can lead to step-by-step replacement of traditional organic luminophores by QDs. Luminescent nanosensors sensitive to metal ions or ions of hydrogen which luminescent response based on changes of efficiency of nonradiative resonant energy transfer from photoexcited nanocrystal to some acceptor of energy are intensively studied [3]. In present work formation of QD/azo dye complexes in different hydrophobic solvents due to coordination bonding of molecules with metal ions of the nanocrystal shell has been studied by means of absorption/luminescence methods. Hydrophobic core/shell CdSe/ZnS QDs were used in the experiments while 1-(2-pirydilazo)-2-naphtol (PAN) which forms chelate complexes with ions of different metals [4]. It was expected that in this case molecules are in direct contact with QD surface that results in total quenching of luminescence of QD in QD/molecule complex. The presented results are support our expectation. The QD/PAN complexes in toluene solution were embedded in polymer film. It was found that when this film is placed in water containing Co or Ni ions the QD luminescence appears with intensity proportional to concentration of ions in the solution. The characteristic changes of absorption spectra of the films were simultaneously observed, namely, disappearance of absorption bands of Zn/PAN complex and growth new bands associated with complexes of azo dye with Co2+ or Ni2+. The data show that diffusion Co or Ni ions from water solution to polymer film containing QD/PAN complexes results in dissociation of these complexes followed by appearance of QD luminescence. It was concluded that polymer films with embedded QD/PAN complexes can be considered as luminescence nanosensor. Absence of sensor luminescence without ions shows principal possibility to reach sensitivity allowing detection of single metal ion. 1. I.L. Medintz, H. Mattoussi, A.R. Clapp, Intl Journal of Nanomedicine, 3(2), p. 151 (2008). 2. А.В. Федоров, А.В. Баранов «Оптика квантовых точек». в сб. Оптика наноструктур. Под ред. А.В. Федорова: СПб. «Недра», 2005 г. C. 181. 3. P. T. Snee, R. C. Somers, G. Nair, J. P. Zimmer, M. G. Bawendi, and D. G. Nocera. J. Am. Chem. Soc. 128, p.13320 (2006). 4. Иванов В. М. Гетероциклические азотсодержащие азосоединения // М.: Наука. 1982. – С. 270.

81

ATOMIC FORCE MICROSCOPY STUDY OF J-AGGREGATE NANOSTRUCTURES

O.M. Perelygina1, V.V. Prokhorov2, D.A. Lypenko1,

E.I. Mal’tsev1, A.V. Vannikov1

1 - A.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS 2 - M.M. Shemyakin & Yu.A. Ovchinnikov Institute of Bioorganic Chemistry RAS

dremeself@gmail.com

Molecular aggregates play an important role in molecular optoelectronic devices and thus have attracted great attention in both fundamental and applied research on bridging the gap between the physics of a single molecule and bulk molecular crystal. J-aggregates are specific molecular assemblies. They are characterized by a very narrow and intense absorption and emission bands as well as by coherent excitation phenomena. Proposed theoretical models, describing the relationship between the optical properties and the molecular arrangement within the molecular aggregates, show that the aggregate structure reflects its optoelectronic properties. Therefore, direct experimental investigation of the morphology of aggregates is of particular importance. Here we report recently obtained results on the observation of J-aggregate structures, based on some cyanine dyes, e.g. a triethylammonium salt of 3,3’-di(γ-sulfopropyl)-5,5’-dichloro-thiacyanine, located on mica surface and in the very thin (several nm thick) conducting polymer layers. Some of these structures are shown in the micrographs below.

nm

0 1 2 3

4

2

0µm

1122

1-1 1.05nm 2-2 2.09nm

a b

1 µm

Fig. 1. Topographical AFM images and cross-sectional profiles of ribbon-like J-aggregates on mica (a) and in a polyaniline film (b). Implications of the molecular alignment in the supramolecular aggregates include the existence of structural units with highly ordered molecular structures. On the bases of the obtained AFM microscopy data various supramolecular models of the studied J-aggregates are discussed. This work was supported by The International Science and Technology Center (project no. 3718). Authors are grateful to B.I. Shapiro for synthesizing of the cyanine dyes.

82

NEW EUIII AND TBIII HEXAFLUOROACETYLACETONATES WITH BIDENTATE O-DONOR LIGANDS:

SYNTHESIS, STRUCTURE AND OPTICAL PROPERTIES

D.N. Pleshkov1, S.V. Eliseeva1, K.A. Lyssenko2, L.S. Lepnev3, O.V. Kotova1, N.P. Kuzmina1

1 – M.V. Lomonosov Moscow State University, Moscow, Russia

2 - A.N. Nesmeyanov Institute of Organoelement Compounds RAS, Moscow, Russia 3 - Division of Optics, P.N. Lebedev Institute RAS, Moscow, Russia

dimas666-hell@mail.ru

For cleaver design of new functional materials it is necessary to establish correlation between their composition, structure and properties. It is well known that the insertion of suitable neutral ancillary ligands into the inner coordination sphere of coordination compounds is one of the easiest ways to control and modify their functional properties (e.g. luminescence, thermal stability, volatility etc.). The feasibility of this method on many different classes of complexes was demonstrated. Herein, new mixed-ligand lanthanide hexafluoroacetylacetonates [Ln(hfa)3(Q)] (Ln = EuIII , GdIII , TbIII , LuIII ) with bidentate O-donor ligands (Q): 1,4-diacetylbenzene (acbz), 1,4-diacetoxybenzene (acetbz), 1,4-dimethyltherephtalate (dmtph) and 2,2-dipyridyl-N,N’-dioxide (dipyox) were investigated. In spite that lanthanide β-diketonates are widely investigated, there is no data about structure and functional properties of Ln(hfa)3 with neutral bridging bidentate O-donor ligands. Synthetic conditions were optimized to obtain pure complexes with general composition [Ln(hfa)3(Q)]. The laser desorption/ionization mass spectra of [Eu(hfa)3(Q)] exhibit mixed-ligand ions [Lnx(hfa)y(Q)z]

+. Single crystal X-ray diffraction analysis shown that [Eu(hfa)3(acbz)], [Gd(hfa)3(acbz)] and [Tb(hfa)3(acbz)] are isostructural and crystallize in triclinic crystal system, while [Eu(hfa)3(dmtph)] in monoclinic one. For the first time the bridging function of chosen bidentate O-donor ligands was successfully utilized for formation of polymeric mixed-ligand lanthanide complexes, [Ln(hfa)3(acbz)]n and [Ln(hfa)3(dmtph)]n. In order to estimate the role of mixed-ligand complexes formation on optical properties (i) the triplet state energy levels of neutral ligands were determined from the photoluminescence spectra of Lu(NO3)3(Q)⋅nH2O, and (ii) quantum yield values, lifetimes of the excited states (at 77 and 298 K) of [Ln(hfa)3(Q)] were compared with initial Ln(hfa)3⋅2H2O (Ln = EuIII , TbIII ). The results of thermal analysis in nitrogen atmosphere shown that [Ln(hfa)3(Q)] are stable up to ~170–210°С. Electronic ionization mass-spectrometry together with vacuum sublimation and thermal analysis experiments shown the possibility of congruent sublimation of [Ln(hfa)3(Q)] (Q = acetbz, dmtph, dipyox). Thin films of these compounds were obtained and their morphology and optical properties were investigated. This work is supported through Russian Foundation for Basic Research (09-03-00850a).

83

SYNTHESIS AND OPTICAL PROPERTIES OF HIGHLY LUMINESCENT CdS QUANTUM DOTS

A.E. Raevskaya, G.Ya Grodzyuk, A.L. Stroyuk, S.Ya. Kuchmiy

L.V. Pysarzhevsky Institute of Physical Chemistry of Nat. Acad. Sci. of Ukraine, Kyiv, Ukraine

alraevskaya@ukr.net

Semiconductor nanoparticles with quantum-size effects (quantum dots) are now widely used as the luminescent labels in the research of biological objects and as emitting components of light-emitting devices (LEDs). Synthetic approaches to the water-soluble highly-luminescent quantum dots, which are of special interest for the biophysical research, still remain at the stage of development. At the same time, the LED technologies require the procedures of formation of the highly-ordered layers of quantum dots to be developed. Probably the most advantageous among these procedures with regard to the aqueous quantum dot colloids consists in the layer-by-layer assembly using polyelectrolyte molecules, specifically, polyethyleneimine (PEI). The report describes an attempt to address these two problems simultaneously, employing PEI both as a stabilizer of the CdS nanoparticles in aqueous solutions and, in prospect, as an assembling agent at the formation of the highly-ordered quantum dot films. Using this approach the ultrasmall CdS particles were produced at 60-80 °С, displaying the absorption threshold shifted by more than 120 nm to shorter wavelengths as compared to the absorption threshold of the bulk CdS. The strong hyspochromic shift and development of the fine structure of absorption

band, visible as a trio of the distinct peaks at 357, 326 and 264 nm, allow to assess the synthesized CdS nanoparticles as quantum dots experiencing strong spatial confinement of the exciton. The estimations done by the semiempirical model [1] showed the CdS quantum dots being as small as 1.6 nm. The size dispersion, calculated from the spectral width of the three peaks mentioned, does not exceed 1.5%. The quantum yield of photoluminescence (PL) of the CdS quantum dots is as high as 15%, thus closing to the highest values obtained for CdS nanoparticles synthesized in octadecene at 300 °С (17%) [2]. It was found than the PEI-stabilized CdS quantum dots have remarkable stability toward aggregation up to the semiconductor concentration of 0.1-0.2 M, i.e. the CdS content three orders of magnitude higher than the

aggregation stability limit for typical polymer-stabilized CdS colloids. There exists an optimal component concentration range producing the quantum dots of the smallest size and size dispersion. The special features of the PEI-stabilized CdS quantum dots produced in the optimal conditions led to a conclusion about the formation of some "magic" CdS clusters having remarkable thermal and aggregation stability. The structure of the "magic" cluster is probably close to that of a well-known cluster Cd32S14(SC6H5)36 with the cadmium sulfide core size of 15 nm, which has very close spectral properties [1]. [1] Torimoto T., Kontani H., Shibutani Y., Kuwabata S., Sakata T., Mori H., Yoneyama H. J.

Phys. Chem. B 105 (2001) 6838. [2] Sapra S., Mayilo S., Klar T.A., Rogach A.L., Feldmann J. Adv. Mater. 19 (2007) 569.

300 400 500 600 7000,0

0,3

0,6

0,92

Inte

nsity

, arb

.u.

Wavelength λ, nm

1

The absorption (1) and PL (2) spectra of the PEI-stabilized CdS quantum dots. The PL excitation wavelength is 320 nm.

84

STARLIKE OLIGOTHIOPHENESILANES FOR PHOTOVOLTAIC APPLICATIONS

E.A. Shumilkina1, S.A. Ponomarenko1, P.A. Troshin2,

E.A. Hakina2, N.M. Surin1, A.M. Muzafarov1

1 - ISPM RAS, Moscow, Russia 2 - IPCP RAS, Chernogolovka, Russia

memoza85@mail.ru

The possibility of regulation of photophysical characteristics of macromolecules plays an important role in the creation of functional materials for organic electronics and photonics. One of the drawbacks of linear π-conjugated polymer systems is anisotropy of the optical and electrical properties, as a result of which strict control over the molecular orientation during the production of different devices is required. Possible solution to this problem is the development of branched and hyperbranched macromolecular systems with isotropic properties. A prerequisite for this work was the successful application of starlike terthiophenesilanes in organic photovoltaic devices described in the literature [1]. Previously we have prepared a number of linear and starlike bithiophenesilanes with significant luminescence [2]. In this work we synthesized a series of star oligothiophenesilanes with varying lengths of conjugated oligothiophenes fragments (Fig. 1). Solubility of these compounds is provided both by three-dimensional structure of tetra-substituted silicon compounds and terminal solubilizing n–hexyle or 2-ethylhexyle groups R. Study of the optical properties of the compounds obtained under transition from ter- to quinquethiophenesilanes showed the expected red-shift of the absorption maximum from 385 nm to 437 nm, as well as an increase of the luminescence quantum yield from 8% to 21%. The complex study of the photovoltaic properties of the composites prepared from the compounds obtained and fullerene derivatives С60 and С70 showed perspectivity for their usage in the solar cells. The maximum efficiency of the photovoltaic cell obtained have raised with increasing of the conjugation length and reached 1.0% for the quater- and and 1.3% for the quinquethiophenesilane. In the presentation especially the synthesis of this series of compounds, as well as their optical, thermal and photovoltaic properties will be considered. This work was supported by RFBR (grant 07-03-01037), Federal Agency for Science and Innovations (Contract No. 02.513.11.3382) and by the Presidium of the Russian Academy of Sciences (Program No. 27). Literature: 1. S. Roquet, R. de Bettignies, A. Cravio, J. Roncali, J. Mater. Chem. 2006, 16, 3040-3045. 2. Shumilkina E.A., Borshchev O.V., Ponomarenko S.A., Surin N.M., Pleshkova A.P.,

Muzafarov A.M. Mendeleev Commun., 2007, 17, 34-36.

SiS

S

S

SR

R

R

R

n

n

n

n

n = 3 - 5R= C6H13 или C8H17

Fig. 1. The generalized chemical formula starlike

oligothiophenesilanes.

85

SYNTHESIS AND PHOTOLUMINESCENT PROPERTIES OF SOME LANTHANIDE COMPLEXES (LN = EU3+, GD3+, TB3+, LU3+)

WITH ORTHO-SUBSTITUTED PHOSPHORYLPHENOLS

S.V. Shuvaev1, O.V. Kotova1, L.S. Lepnev2, N.P. Kuzmina3, V.E. Baulin4, A.Yu. Tsivadze4

1 - Department of Material Sciences, M.V. Lomonosov Moscow State University, Russia

2 - Division of Optics, P.N. Lebedev Institute RAS, Moscow, Russia 3 - Department of Chemistry, M.V. Lomonosov Moscow State University, Russia 4 - Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia

sergeyshuvaev@gmail.com

Nowadays, coordination compounds of rare earth elements with organic ligands play an essential role in development of new luminescent materials: OLED, sensors, bioimaging etc. In this work the main consideration is given to coordination compounds of Eu3+, Gd3+, Tb3+ and

Lu3+ with ortho-substituted phosphorylphenol ligands (Fig. 1). The synthetic route of such ligands is well established and opens wild possibilities for the variation of their denticity, complexes formation ability and physicochemical properties. However, in spite of high potential interest, no information concerning phosphorylphenolate complexes with lanthanides has been found to date. The crystal structure of HL1 has been determined for the first time and the intermolecular hydrogen bounds are the key characteristic of this crystal structure, which is usual for organic acids. Thus, lanthanide complexes were synthesized by an interaction of the potassium salt of HL and corresponding lanthanide nitrate according to the following scheme:

323 LnLKL 3OHLn(NO) →+⋅ . The composition of

the complexes has been determined according to elemental and IR-spectroscopy as well as MALDI/LDI, NMR and thermal analyses. All these methods proved the formation of the expected compounds. The analysis of photoluminescence spectra (λex = 337 nm) of gadolinium and lutetium complexes at 77 and 298 K results in determination of the triplet state levels for these ligands at ~23000 cm–1 and for such class of the ligands the effective photoluminescence sensibilization is possible only for complexes contains of terbium ion.

This work is supported through Russian Foundation for Basic Research (09-03-00850a).

OH

P

O

OH

P

O

OH

P

O

O

O

HL1

HL2

HL3

Fig. 1. Structural formulas of

ortho-substituted phosphorilephenoles (HL).

86

A NEW TECHNIQUE TO FABRICATE DIFFRACTIVE OPTICAL ELEMENTS ON THE BASIS OF PERMOLECULAR STRUCTURES

V.S. Solovjev1, A.V. Volkov2, N.A. Rasshchepkina3

1 - A.N. Nesmeyanov Institute of Organoelement Compounds RAS

2 - Image Processing Systems Institute 3 - Samara Aerospace University

Solovjev@polly.phys.msu.ru

To design high-efficiency diffractive optical elements (DOEs) the calculation there of should be conducted in the electromagnetic theory approximation. The calculations suggest that the characteristic features of the DOEs are in the range from several wavelengths to one tenth of the operating wavelength. In the optical range, the minimal wavelength is 0.4 µm. In this connection, there is a need for a technique to fabricate arrayed periodic structures, capable of producing the minimal DOE characteristic feature as small as 0.04 µm. We propose a novel combined technique to fabricate the DOEs in a new recording medium capable of building arrayed high-frequency periodic structures through self-organization. A traditional lithographic technology makes it possible to control these structures. A siloxane oligomer applied onto a substrate serves as the recording medium. In this work, we report the formation of permolecular structures on the surface of varied-thickness siloxane films exposed to a directed flow of IR light. For different siloxane polymers, the width of the resulting permolecular structures formed in the 2µm-films is 5 µm. Similar experiments are conducted for the film thickness in the range of 0.1 – 0.15 µm. For the thinner films, the width of the permolecular structures was 0.4 – 0.6 µm. In this way, we show that the transverse size and period of the permolecular structures can be governed by the film thickness. The permolecular structures are formed on different substrates. Depending on the conditions, different types of the permolecular structures are formed: globular, lamellar, and cylindrical. We show that by preliminarily creating, through conventional lithographic techniques, a specific relief configuration it is possible to form the permolecular structures of designed size, period, and direction. The new combined DOE fabrication technique includes:

• formation on the substrate – through the conventional lithography – of a specific configuration that will determine the direction and length of the permolecular structure;

• application of a thin siloxane film onto the substrate; and • formation of the permolecular structure.

87

POLYMER/NANOCARBONS COMPOSITE MATERIALS FOR PHOTONICS

N.G. Spitsina, A.S. Lobach, M.G. Kaplunov

Institute of Problems of Chemical Physics RAS, Chernogolovka

spitsina@icp.ac.ru

The discovery of a very efficient photoinduced electron transfer from conjugated polymer (CP) to [60]fullerene opened up new aspects with potential applications of nanocarbons in fotonics, non-linear optics, optoelectronics and organic photovoltaics (PV). The core of PV devices is the interpenetrating biscontinuous donor/acceptor molecular network, where CP acting as a donor (D) and nanocarbon materials (NCM) acting as an electron acceptor (A) [1]. A series of NCM has been synthesized: C60; azahomo[60]fullerenes and (4-6) poly(amino)[60]fullerenes; [60]fullerene dimmers; single-walled carbon nanotubes. The structure of the NCM was studied by cyclic voltammetry, 13C NMR-, UV-VIS-NIR-, FTIR-, Raman spectroscopy [2-4]. Photoluminescence quenching experiments, current-voltage measurements were performed on sandwich type cells based on CP [MEH-PPV, P3HT] and CP/NCM blend films to investigate the charge transfer process. Preliminary results indicate that NCM under investigations have a potential for use as electron acceptors in polymeric solar cells. Series of microscopy methods TEM and AFM (tapping mode) has been used to investigate CP/NCM blend film microstructure. The morphologies of NCM under investigation and C60 species in MEH-PPV matrix are sufficiently different. Thus, we seen that azahomo[60]fullerene derivative formed linear extended structures (rod-like formations - thickness is approximately 100 nm and length of several micrometers), in contrast with C60 which formed a ball-shaped aggregates with dimensions around 10 nm. Microstructure – properties correlation of the CP/NCM blend film were discussed. Also, we discuss the way of increasing anisotropic properties of the polymeric matrix by means of design of NCM and D-A self-organization towards the desired nanomorphology of the composite film. This work was supported by RFBR, Grant No. 08-03-01017. [1] N.S. Sariciftci, L. Smilowitz, A.J. Heeger, F. Wudl. Science, 258 (1992) 1474. [2] N.G. Spitsina, I.P. Romanova, A.A. Lobach, I.K. Yakuschenko, A.S. Lobach, M.G.

Kaplunov, I.V. Tolstov, M.M. Triebel, and E.L. Frankevich. Fullerenes, Nanotubes, and Carbon Nanostructures, 14 (2006) 435-439.

[3] A.S. Lobach, I.S. Ryzhkina, N.G. Spitsina, E.D. Obraztsova. Phys.Stat.Sol. (b), 244 (2007) 4030-4034.

[4] N.G. Spitsina, M.V. Motyakin, И.O. Bashkin, K.P. Meletov. J.of Phys.: Cond. Mat., 14 (2002) 11089-11092.

88

DESIGNING FULLERENE/POLYMER BULK HETEROJUNCTION SOLAR CELLS WITH ADVANCED ACTIVE LAYER MORPHOLOGIES

D.K. Susarova1, P.A. Troshin1, S.D. Babenko2,

R.N. Lyubovskaya1, V.F. Razumov1

1 - IPCP RAS 2 - Institute for Energy Problems of Chemical Physics RAS (Branch)

diana-susarova@yandex.ru

It was shown recently that an active layer morphology in organic solar cells can be controlled using some additives that serve as co-solvents dissolving one component of the blend much better than another. Here we showed that addition of 5-10% (v/v) of 1,8-octanedithiol (ODT) to chloroform used as a solvent for casting of the P3HT/PCBM blend films resulted in improved photovoltaic performances, particularly, due to increased fill factors. The obtained data strongly suggest that addition of ODT leads to precipitation of pure P3HT and formation of the electron-blocking interlayer between the anode and the photoactive blend. Similarly, pure fullerene phase placed between the aluminum cathode and the fullerene/polymer blend can serve as a hole-blocking interlayer. To achieve this, fullerene derivatives with higher solubilities than PCBM and P3HT were applied as additives. These additives also improved performance of the devices. Finally, we designed organic cocktails comprising co-dissolved “highly-soluble fullerene”, PCBM, P3HT and ODT. When solvent is evaporated from such a cocktail, a thin film of the pure P3HT is formed first, then PCBM/P3HT blend layer is growing up and, at the end, almost pure “highly soluble fullerene” is deposited on the top. Thus we showed that our cocktail approach gives “anode//polymer/fullerene+polymer/fullerene//cathode” device architectures with the improved active layer morphologies and photovoltaic performances.

89

PHOTODISSOCIATION OF COMPLEXES OF QUANTUM DOT / ORGANIC MOLECULES EMBEDDED IN THIN POLYMER FILMS

E.V. Ushakova, A.O. Orlova, A.V. Baranov

St.Petersburg State University of Information Technologies, Mechanics and Optics, Russia

a_v_baranov@yahoo.com

Last years hybrid nanostructures comprised bonded quantum dot (QD) and organic molecules combined attract great attention. Such complexes is considered as a perspective structures for fabrication of luminescent sensors for quantitative analysis of presence of different analytes in liquid solutions. We have studied one of such luminescent nanosensors for detection of some metal ions in water solution. The sensor is based on complex QD/PAN, where QD is the CdSe/ZnS core/shell quantum dot and PAN is the azo dye molecule, 1-(2-pirydilazo)-2-naphtol, embedded in thin polymer film. In absence of ions QD luminescence is practically quenched due to resonant nonradiative energy transfer from QD to molecule. When the film is placed into water solution containing metal ions they diffuse into film and stimulate dissociation of the QD/PAN complexes. As a result, QD luminescence is arisen with intensity proportional to the ion concentration in analyzed solution. Since the luminescence is excited by optical radiation, the question is arisen about possible photodissociation of the sensor and its influence on parameters of the luminescence response of the sensor. This information is important for determination of the excitation light parameters needed for sensor utilization for analytical applications. In the report we well present results of comparative studies of changes in luminescence intensity and luminescence lifetime of QD/PAN complexes embedded in polymer films under exposure of laser light. The experiments were performed by the use a laser scanning luminescent microscope with possibility of time-resolved measurements (Microtime100, PicoQuant) at room temperature. It has been found that photodissociation of QD/PAN complexes with appearance of free luminescent QDs takes place in studied systems under strong laser irradiation. The corresponding incident light intensity and energy dependencies of QD luminescence intensity and lifetime will be presented. Finally we found acceptable parameters of incident light allowing utilization QD/PAN complexes as a dissociative luminescent sensor.

90

SERS, SPECTROPHOTOMETRY AND AFM STUDY OF PHOTOCHROMISM OF SPIROCYCLIC COMPOUNDS

ON NANOSTRUCTURED METAL FILMS

G.T. Vasilyuk1, S.A. Maskevich1, A.E. German1, I.F. Sveklo1, B.S. Lukyanov2, L.A. Ageev3

1 - Y. Kupala Grodno State University, Grodno, Belarus

2 - Institute of Physical and Organic Chemistry, South Federal University, Rostov-on-Don, Russia

3 - V. Karazin Kharkiv National University, Kharkiv, Ukraine vasilyuk@grsu.by

Spiropyrans and spirooxazines are compounds performing photochromic properties in solutions as well as in solid matrices. In the presence of metal these compounds receive additional important properties. Chelate complexes spirocyclic molecules with metals allow to receive thermostable photoswitches. At adsorption of molecules on metal surface with nanosized roughnesses the enhancement of photochemical processes as well as the enhancement of Raman scattering signal are observed also [1, 2]. Use composit nanopartices can as to provide necessary thermal stability photochromic molecules thanks to thermal energy sorbtion by a metal kern of such particle, and to increment efficiency of phochromism at the expense of a enhancement of an electromagnetic field near to a metal surface.

In the capacity of active substrates are used sols and granular silver films (SF) as well as photosensitive thin films of silver chloride with impurity granular silver (films AgCl-Ag). They can ensure additional (at the expense of collective effects) a enhancement of a Raman scattering signal thanks to presence periodic nanostructuring, optical attained. The photoinduced phenomena occuring in films AgCl-Ag, have similar features with the phenomena in photochromic materials and can be used for demonstration of various resonant nonlinear effects. A photosensitivity of thin-film system AgCl-Ag is interesting also in itself as it is related to discrete state Ag in film AgCl and can be referred to a number of the abnormal phenomena (nanophotonics), observed in medium with nanosized particles. In the present work by surface enhanced Raman spectroscopy (SERS), spectrophotometry and atomic-force microscopy (АFМ) methods features spirocyclic molecules photochromic conversions near nanostructured metal surfaces are studied, and also receive for this purpose original nanostructured systems and studied their structural (surface morphology) and optical (including enhancing) properties.

Efficiency raise of photochromic conversions near nanostructured metal surfaces is revealed. SERS spectra of various spirocyclic compounds on various types of nanostructured systems (granular SF, films AgCl-Ag) are received and interpreted. The SERS bands assigned to in-plane vibrations, transforming on unit irreducible representation Ag are most intensive. This work was supported by Byelorussian Foundation for Basic Research (Grants F07K-096, F08R-229) and Russian Foundation for Basic Research (Grant 08-03-90029 Bel)

1. Nitzan, A., Brus, L.E., J. Chem. Phys., 1981, vol. 74, p. 5321 2. Nitzan, A., Brus, L.E., J. Chem. Phys., 1981, vol. 75, p. 2205

91

DYNAMICS OF PHOTOPROCESSES IN NOVEL BIFUNCTIONAL SALICYLIDENEIMINOSPIRONAPHTHOXAZINES

N.L. Zaichenko1, P.P. Levin2, I.R. Mardaleishvili1, A.I. Shiyonok1,

L.S. Kol’tsova1, O.Yu. Os’kina1, A.S. Tatikolov2

1 – N.N. Semenov Institute of Chemical Physics RAS, Moscow, Russia 2 – N.M. Emanuel Institute of Biochemical Physics RAS, Moscow, Russia

zaina@polymer.chph.ras.ru

A row of novel photobifunctional compounds (PBC) which molecules combine two different photosensitive fragments – a spirooxazine moiety and substituted salicylideneimine (SA) one - were synthesized for the first time. Two different photoprocesses can occur in these compounds after UV-light absorption: C-O spiro-bond dissociation and excited state intramolecular proton transfer (ESIPT).

N

Me

MeMe

O

N OHNCH

R

N

Me

Me Me

O

N OHNCH N

(1) R = H(2) R = NO2

(3)

Three photoproducts, namely open merocyanine form of spironaphtoxazine fragment linked with enole (BE ) or cis-keto-form (BKc ) of SA fragment and trans-keto-form of SA linked with closed spiroform of spirooxazine (AKt), were registrated in solutions by nanosecond laser flesh-photolysis. Spectral-kinetic characteristics of these photoproducts were studied, their quantum yields were measured. All three above mentioned photoproducts with λmax = 500 (АКt), 600 (ВE) и 620 нм (BKc). were observed in MeOH solutions after 337 nm pulse excitation in the time interval ≥ 10 ns. Only two photoproducts - ВE with λmax = 600 nm and АКt with λmax = 500 nm – were observed in toluene solutions of PBCs at the same conditions. It was established that two photoprocesses –spirocycle cleavage and ESIPT – are concurrent and independent in the PBCs under study. Solvent nature has a dominant influence on the number of photoproducts of PBCs photolysis, kinetics and mechanism of their bleaching reactions. In MeOH solutions a formation of BKc form from BE* is possible. Influence of the substituents in SA fragment of PBC molecules on the ratio of two photoprocesses and the lifetime of photoproducts is discussed. Presidium of RAS (Program «Development of methods for synthesis of chemical compounds and creation of new materials») financially supports this work.

92

PHOTOLUMINESCENCE KINETICS OF (ZINC)TETRAPHENYLPORPHYRIN-FULLERENE

CHARGE-TRANSFER COMPLEXES

I.B. Zakharova1, G.M. Ermolaeva2, O.E. Kvyatkovskii3, L.V. Belyakov3

1 - State Polytechnic University, St.Petersburg, Russia 2 - RC "S.I. Vavilov State Optical Institute", St.Petersburg, Russia

3 – A.F. Ioffe PTI RAS, St.Petersburg, Russia zakharova@rphf.spbstu.ru

Porphyrin-fullerene dyads and complexes have been the subject of intense research as artificial systems that efficiently convert sunlight into energy [1]. In this work the interaction of molecular components, as well as optical and photoelectrical properties of С60-Zn(II)tetraphenylporphyrin (ZnTPP) thin films and solutions has been investigated. Ab initio calculations of optimized geometry and electronic structure ZnTPP-C60 have been carried out. It is shown that due to the acceptor properties of С60 molecule, the pair С60 - ZnTPP forms a stable charge transfer complex with a binding energy of 0.6 эВ, distance between the molecular components of 0.25 nm and the amount of transferred charge of 0.4 ē, HOMO-LUMO gap Eg is 1.38 eV. The photoluminescence (PL) spectra were measured for the toluene solutions and thin films, which were grown by in the quasiequilibrium conditions on the CaF2, Si, KBr substrates. The UV-Vis-NIR absorption studies and Raman scattering investigations are described in [2]. The formation of the charge-transfer complex leads to the quenching of the photoluminescence in the region of ZnTPP lighting (620 nm) and to the increase of luminescence intensity in the region peculiar to C60 (750 nm), as well as to the changes in fluorescence kinetics. It is shown that C60-ZnTPP PL peak position strongly depends on substrate type. PL kinetics has been explored both on the wavelength of 560 nm corresponding to the absorbance maximum for free ZnTPP molecule and 343 nm where the С60 molecule has the maximum. We have found that the PL time decay is an order of magnitude lower for the ZnTPP thin solid films than that for the ZnTPP toluene solutions. The time decay constant is found to be 300 ps, which is typical for the π*-π transitions. We have found a phenomenon of luminescence condensation: the response duration decreases with the increase of the stimulating emission power density. The kinetic curves demonstrate the two- stage photoinduced intramolecular charge transfer with time constant about 2 ns. LITERATURE 1. Guldi D.M. Pure Appl. Chem., 2003, 75, 1069-1075. 2. Zakharova I.B., Donenko E.G., Biryulin Yu.F., Sharonova L.V. Fullerenes, nanotubes and carbon nanostructures, 2008, 16, 424-429.

93

PHOTOCHEMICAL PROCESSES IN SELF-ORGANIZED MULTIPORPHYRIN COMPLEXES

E.I. Zenkevich1, E.I. Sagun2, V.N. Knyukshto2, C. Von Borczyskowski3

1 - National Technical University of Belarus, Minsk, Belarus

2 - B.I. Stepanov Institute of Physics, Minsk, Belarus 3 - Institute of Physics, Chemnitz University of Technology, Chemnitz, Germany

zenkev@tut.by

At present, supramolecular chemistry is reaching highly elaborate levels of sophistication and the analysis of the cooperative behaviour of subunits within controlled spatial assemblies involving molecular recognition, catalysis, molecular devices, etc. According to the nowadays conception, the co-ordination of the porphyrin metal ions to additional ligands via amino acid side chains in natural protein complexes might affect the excited states deactivation of porphyrins, the rate constants and the efficiency of the energy migration (ET) and charge separation as well as might influence on the interaction of the porphyrin subunits with external reactants including molecular oxygen (O2). The goal of the report is the comparative analysis of the extra-ligation influence on the deactivation of S1- and T1-states for nanoscale self-assembled multiporphyrin arrays (triads and pentads) as well as on their interaction with molecular oxygen in solutions using steady-state, laser nanosecond fluorescent and pump-probe kinetic data and direct measurements of singlet oxygen (1∆g) emission (1.27 µ). Triad Pentad

The formation of self-assembling porphyrin triads and pentads has been succeeded using two-fold extra-ligation of both central Zn ions of the dimers with two nitrogens of meso-pyridyl rings in the corresponding di- and tetra-pyridyl-containing free base porphyrin extra-ligands based on a “key-hole” principle. The triads and pentads were formed at 295 K during a titration of the dimer solution (C∼1⋅10-6 M÷4⋅10-6 M) with

an extra-ligand solution (C∼0.3⋅10-4 M÷2⋅10-4 M).For pyridinated dimers (precursors of the triads and pentads) at 295 K T1-states quenching by molecular oxygen depends on the spacer flexibility and donor-acceptor interactions with pyridine. The non-radiative relaxation of the dimer S1-state in self-assembled triads and pentads takes place within ∼1.6 ps with respect to τS=1,2 ns for individual dimer. The main reason of this quenching is due to the competition of the energy migration (EM) and photoinduced electron transfer (PET) processes to the extra-ligand depending on the spectral-kinetic and redox properties of the interacting subunits as well as on temperature and the solvent polarity. Thus, the direct population of the dimer T1-state via intersystem crossing S1(

1Dimer*)∼∼> T1(3Dimer*) with a rate constant of kISC∼(5-

7)⋅107s-1 is probably slow. Instead, fast EM and ET processes are followed by the effective population of the extra-ligand T1-state. The role of structural organisation of triads and pentads is most readily understood upon their interaction with molecular oxygen in liquid solutions at 295 K. Bimolecular rate constants of the extra-ligand T1-states quenching by O2 are decreased by 1.4-1.8 times with respect to those found for individual monomeric porphyrins. In addition, quantum yields of singlet oxygen generation by triads and pentads are noticeably smaller relative to the corresponding data for free base porphyrin monomers. These effects are explained by the screening action of a strongly quenched Zn-porphyrin dimer subunit limiting the access of oxygen molecule to the excited extra-ligand. This work was supported by Belarus Programs Nanoteckh 6.18 and KMS 17as well as by ECO-NET Project (program No 18905YD).

94

SYMPOSIUM “MOLECULAR PHOTONICS” Dedicated to Academician A.N. Terenin

ORALS

INTERMOLECULAR INTERACTIONS AND PHOTOPROCESSES IN MOLECULAR SYSTEMS

V.Ya. Artyukhov, G.V. Mayer

Tomsk State University, Russia

artvic@phys.tsu.ru

In molecular spectroscopy and luminescence the basic displays universal (physical) ММВ consist in changes of a position, a form and an intensity of bands of radiation and absorption. Specific (quasi-chemical) ММВ can cause occurrence (or disappearance) new bands of absorption and a luminescence. From the end of 80th years we carried out theoretical researches of the phenomenon of electronic excitation energy transfer in bichromophoric organic compounds and molecular systems. During researches it has been developed quantum-chemical model of studying of the orbital nature and spatial localization of electronic states and features of course of photoprocesses in such systems. Determined that necessary condition for realization intermolecular (interchromophoric) photoprocess is a delocalization of wave functions of electronic states, participating in photoprocess. This delocalization results from intermolecular interaction a component (fragments) system. It is shown, that intermolecular photoprocesses on the nature (as the interaction initiating electronic transition) do not differ from the intramolecular photoprocesses. Quantum-chemical techniques of an estimation of the rate constants of intramolecular photophysical processes can successfully be applied to estimate the rate constants of intermolecular photophysical processes Intermolecular nonradiation energy transfer of electronic excitation is only a special case of influence of intermolecular interaction on spectral-luminescent and photochemical properties of organic compounds. The correct description of mechanisms and laws of intermolecular photoprocesses is necessary at research of suppression of a luminescence (including, concentration), charge transfer complexes and any polymolecular systems. In the given report influence of intermolecular interactions on electronic states and spectral-luminescent properties of bimolecular systems is considered. It is shown, that as the initial stage of quantum-chemical research of this influence the analysis of spatial structure of one-electronic states (molecular orbitals) is necessary. The assumption of an opportunity of neglect of overlap of molecular orbitals in contact complexes is incorrect and leads to fallacies on the photophysics of such complexes.

95

AN EFFECT OF THE THIRD COMPONENT ON THE LUMINESCENCE OF THE NANO-SIZED NAPHTHALENE–CYCLODEXTRIN COMPLEXES

V.G. Avakayn1, V.B. Nazarov2, T.G. Vershinnikova2,

V.Y. Rudyak1, M.V. Alfimov1

1 - Photochemistry Center RAS, Moscow, Russia 2 - Institute of the Problems of Chemical Physics RAS, Chernogolovka, Russia

avak@photonics.ru

A slow formation of the nano-sized complexes of the composition 2:2 occurs in the water solution of naphthalene in the presence of beta-cyclodextrin (b-CD). In the complexes, two naphthalene molecules are oriented parallel to each other and exhibit an eximer fluorescence (EF) [1]. We observed that at an addition of o-carborane, as the third component, eximers are formed rather and even at the lower concentrations (≤10-4М) (see Fig.). However, EF is not

300 350 400 450 500 550

0

2

4

6

8

10

12

3

2

1

lum

ines

cenc

e, r

el.u

n.

wavelength, nm Fluorescence spectra of naphthalene-d8 (C=10-4M) in water solution at 20°С (1), in the presence of b-CD (2),and b-CD and o-carborane (3)

observed if the order of adding components is changed: b-CD – o-carborane – naphthalene. An addition of adamantane as the third component results in to destruction of the complexes of composition 2:2 and to appearance of the long lived phosphorescence at room temperature (PRT) visible without eliminating oxygen [2,3]. Quantum-chemical calculations of the structure and energetics of the naphthalene – b-CD complexes of various composition at the presence and lack of the third components showed that o-carborane stabilizes complexes of the composition 2:2 because it is inserted at them from the side of the narrow entrance to the CD cavity due to the

size of o-carborane molecules. The destruction of the complexes of the composition 2:2 by adamantane occurs due to it possibility to embed into the binary complex naphthalene – b-CD, precursor of the 2:2 complex, resulting in the complex of the composition 1:1:1. The latter along with its surrounding the very strong adamantane – b-CD complexes forms the nanoparticle revealing RTP at the presence of oxygen. However, o-carborane whose molecules are bigger than adamantane is not capable to form complex 1:1:1 and RTP is not observed at the presence of o-carborane. Therefore, changing the structure of the third component we have a possibility to control by the complex structure and as well by a kind of luminescence. Financial support from the Russian Foundation for Basic Research (Grant RFBR No. 09-03-00404) is gratefully acknowledged. 1. V. B. Nazarov, V. G. Avakyan, T. G. Vershinnikova, M. V. Alfimov, Izv. Acad. Sci., ser.

khim. 2000, No. 10, P. 1716. 2. V. B. Nazarov, V. G. Avakyan, T. G. Vershinnikova, M. V. Alfimov, Izv. Acad. Sci., ser.

khim. 2003, No. 4, P. 869. 3. V. B. Nazarov, V. G. Avakyan, E. I. Bagrii, T. G. Vershinnikova, M. V. Alfimov, Izv. Acad.

Sci., ser. khim. 2005, No. 12, P. 2661.

96

PHOTOCHROMIC NANOPARTICLES: PROPERTIES AND APPLICATIONS

V.A. Barachevsky

Photochemistry Center RAS, Moscow, Russia

barva@photonics.ru

The phenomenon of photochromism is of a considerable theoretical and scientific interest owing to reversible photoinduced transformations of substances. It was a base for a lot of applications. This paper is devoted to the analysis of study results, including own, carried out in recent years in the field of the development and properties study of photochromic nanoparticles. . At first, the main types of photochromic nanoparticles as well as methods of their preparation are discussed. Thermally relaxation spirocompounds and thermally irreversible diarylethenes and fulgides were used as photochromic components. Aggregates of the photoinduced merocyanine form of spirocompounds are characterized by specific spectral manifestations which provide the development of photochromic media for frequency-selective optical memory, nonlinear transformation of laser irradiation and making photocontrolled photon crystals. Photochromic coverings of Au и Ag nanoparticles exhibit a different efficiency of phototransformations dependent of a distance between a nanoparticle surface and photochromic molecules. This distance determines an efficiency of an energy transfer between photochromic molecules and nanoparticles. These photochromic systems manifest an interference of the photoinduced absorption change of photochromic compounds and absorption caused by a plasmon resonance. This phenomenon may be used for the development of a new method for nondestructive readout of optical information recorded in photochromic media. The phenomenon of surface plasmon polarization was used for the development of small-size and effective plasmon light modulators. One of the important applications of photochromic metal-containing nanoparticles is the development of photocontrolled nanoconductors changing their conductivity owing to photoinduced changing the length of conjugated bonds into photochromic molecules. The same application can be realized for single-walled nanotubes functionalized by photochromic molecules. Photochromic molecular inclusion complexes provide a required long life-time of the photoinduced merocyanine form for spirocompounds due to formation of intermolecular hydrogen bonds as well as high efficiency of photochromic transformations for diarylethenes owing to the change of a concentration ratio for two isomers of the open form. Other types of photochromic nanoparticles are of special interest for the development of multilayer recording media with very the high concentration of photochromic compounds for three-dimensional bitwise working optical memory. Optical memory of super high information capacity may be made with the use of photochromic recording media possessing a photochromic periodic nanostructures, including quantum dots (QDs), particularly CdSe/ZnS, providing photoinduced emission modulation due to the resonance transfer of photoexcitation energy. Above discussed advances extend an area of application of photochromic materials and make a contribution into the development of organic nanophotonics.

97

PHOTONIC MOLECULAR LOGIC GATES

M.F. Budyka

Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia budyka@icp.ac.ru

Reduction of the size of nanodevices inevitably achieves physical and technological limits, below which exploitation of the 'top-down" principle is impossible. Another - "bottom-up" - approach demands creation and research of the various molecular systems, capable of operating as signal conductors, switches, diodes, elements of memory, and also logic devices. Molecular logic gate (MLG) is a switch, whose input and output signals can accept only values of "0" or "1". Dependence of values of output signals on input is defined by the truth table of the logic (Boolean) function. For the majority of known MLGs the role of input signal carries out some chemical impact - addition of an acid or alkali, ions of metals, other reagents. Application of such devices practically is limited by solutions. In completely photonic MLGs, the role of input and output signals is carried out by photons. Impact on the system consists in irradiation by light of definite wavelength, and readout is made on optical density or luminescence. There are known examples of completely photonic molecular gates which are capable of performing "AND", "OR", "XOR", "INHIBIT" logic operations, and more complex functions of half-adder, encoder-decoder. For maintenance of cyclicity of work in photonic MLGs reversible photochemical reactions are used among which photocyclization/photodecyclization of derivatives of spiropyran, dihydropyrene, dihydroindolizine, dihetarylethene, photoisomerization of derivatives of stilbene and azobenzene, photoinduced electron transfer . The light of different wavelength can be used for readout of output signal of photonic MLG. The response can be various, and thus, it is possible to make different logic operations with the help of the same molecular system. This unique property - compatibility of several logic gates in one device or reconfigurability of logic gate on different type of work - is essentially unattainable for currently used semi-conductor elements where for each logic operation the separate device is necessary. For construction of complex nanosized blocks (nanophotonic devices) from separate MLGs, the self-organization of molecular systems into supramolecular ensembles is supposed to be used. The general problem in this case is the organization of interaction between different MLGs, i.e. signal transfer from one MLG to another. The role of an information carrier in photonic MLG can play singlet-singlet or triplet-triplet energy transfer or photoinduced electron transfer. The work was supported by the Russian Foundation for Basic Research (grant no. 07-03-00891).

98

EFFECT OF SOLVENT POLARITY ON THE PRIMARY PHOTOPROCESSES OF CYANINE DYES

A.K. Chibisov

Photochemistry Center RAS, Moscow, Russia

chibisov@photonics.ru

Photophysical processes and the primary photochemical reactions of cationic and anionic thiacarbocyanine dyes which take place in solvents of different polarity are considered. Cationic thiacarbocyanines containing iodide as a counter ion exhibit in less polar solvent (toluene + DMSO) strong enhancement of the quantum yield of intersystem crossing ΦТ of the dyes due

SS

N N

C2H5 C2H5

+

X- (Cl-, I-)

0 20 40 60 80 1000

1

2

100

200

∆A /

∆A

(100

%)

DMSO, vol. %

to “heavy atom effect” in ion pairs. An increase of ΦТ is accompanied by decreasing of both the quantum yield of fluorescence Φf and trans→cis isomeri- zation Φisomer [1]. Anio- nic sulfopropyl-9-ethyl thiacarbocyanines in less

Relative yield of cis-isomers () and triplets () for Dye with X- = I- and X- = Cl- ( and ∆) in the mixture of DMSO with toluene

polar solvent (dioxane) are characterized by high quantum yield Φf and Φisomer and low ΦТ value. Passing from less polar to solvent of medium and high polarity results in the decrease of Φf and Φisomer. The quantum yield of intersystem crossing is extreme low and hence the main pathway of deactivation of the excited singlet state is internal conversion. In the solvent of medium polarity the reaction of trans →cis isomerization which proceeds via the excited singlet state competes with electron transfer occurring between the dye in the triplet state and methylviologen [2]. Anionic sulfopropyl-9-ethylthiacarbocyanines also demonstrate propensity to aggregation

(CH2)3SO3(CH2)3SO3

SS

N N

OMe

(C2H5)3NH

+

Et

+

- -

400 500 600 700

-0.2

0.0

0.2

35 µµµµs

7 µµµµs

100 ns

∆∆∆∆A

λλλλ, nm

in water and particularly to dimerization. Principal fea- ture of the dimers is their ability to intersystem crossing and the lack of fluorescence [3]. Dimers in the triplet state exhibit the ability to electron transfer with an appropriate donor and/or acceptor and

T-T absorption spectra of Dye in water at different time after laser pulse

hence the dimers serve as photosensitizers of redox reactions [4].

The author thanks Prof. B.I. Shapiro for providing cyanine dyes. This work was supported by RFBR (grant 09-03-00170-a) and DFG.

References: [1] A.K. Chibisov, D.A. Voznyak, N.Kh. Petrov, M.V. Alfimov. High Energy Chemistry, 2009,

v. 43, p.38 (English translation). [2] L.S. Atabekyan, D.A. Voznyak, G.V. Zakharova, A.K. Chibisov. High Energy Chemistry,

2008, v. 42, p.454 (English translation). [3] A.K. Chibisov. High Energy Chemistry, 2007, v. 41, p.200 (English translation). [4] A.K. Chibisov, T.D. Slavnova, G.V. Zakharova, H. Görner. High Energy Chemistry, 2007, v. 41, p.344 (English translation).

99

PHOTONICS OF HEMOGLOBIN AND MYOGLOBIN ACTIVE CENTER S

B.M. Dzhagarov, S.V. Lepeshkevich

B.I. Stepanov Institute of Physics NAS, Minsk, Belarus bmd@imaph.bas-net.by

Mutual action of tetrameric protein hemoglobin (Hb) and monomeric protein myoglobin (Mb) provide for the harvest, transfer and storage of molecular oxygen. The active centre (prosthetic group) of these proteins is heme (iron-protoporphyrin IX complex). In biophysics, biochemistry and biophotonics Hb and Mb are possibly the main models to elucidate the mechanism of cooperative nonlinear interaction in proteins and to determine of the function – structure – dynamics linkage. In our lecture a special attention is paid to the heme-O2 recombination process taking place after fast photodissociative breaking of bond between O2 and ion Fe(II) located in the active center. We present results of nano-, pico-, and femtosecond flash-photolytic studies of excited states and relaxation processes, photodissociation quantum yields, efficiencies and rates of the monomolecular geminate and bimolecular stages of oxygenation reaction in Hb and Mb in solutions and sol-gel matrices. On the basis of the results a full description of oxygen motion in protein matrix will be given and the kinetic mechanism of protein self-regulation of ligand binding will be discussed.

100

ACTIVITY AND SELECTIVITY OF PHOTOCATALYSTS

A.V. Emeline

V.A. Fock Institute of Physics, St.Petersburg State University, Russia emeline_av@hotmail.com

The activity of photocatalysts is characterized by quantum yield of corresponding heterogeneous interfacial photoreaction defined as a ratio between the number of chemically transformed molecules (ions), Nm, (per time unit) and the number of photons absorbed by photocatalyst, Nhv

(abs), (per time unit):

Φ =dN

dtdN

dt

m

h absν ( )

Thus, this parameter characterizes the ability of photocatalyst to transform the energy of absorbed photons into chemical transformation that determines that activity of photocatalyst. In general, the quantum yield of heterogeneous photoreaction is a function of wavelengths of incident light. Therefore, to answer the question, which photocatalysts is more active, one needs to know the spectral distribution of the quantum yield for corresponding photoreaction. The qualitative interpretation of such phenomenon based on one-dimension model considering charge carrier photogeneration, decay, diffusion and surface interaction with molecules will be given during presentation. Experimental spectral dependencies of the quantum yield obtained for different interfacial photoreactions in both gas-solid and liquid-solid heterogeneous systems (such as, phenol(s) – TiO2 and N-, Fe-, Pt- doped TiO2, phenol(s) – ZrO2; hydrogen, oxygen – TiO2 and N- doped TiO2, ZrO2 and F-doped ZrO2) will be presented and discussed in frame of the model. Another significant parameter characterizing the photocatalyst behavior is its selectivity defined as a ratio between the number of molecules of given product, Ni, formed during reaction (per time unit) and the number of reagent molecules, Nr, involved into reaction (per time unit):

S

dNdt

dNdt

i

i

r

=

Thus, this parameter characterizes the ability of photocatalyst to drive the interfacial photoreaction toward the certain reaction product. As evident from experimental data, this parameter also depends on the wavelengths of actinic light. Corresponding experimental dependencies will be demonstrated during presentation. Qualitative explanation will be given on the basis of model considering the spectral variation of the electron transfer pathways. Spectral activity and selectivity of photocatalysts

101

TETRAPHENYLPORPHYRIN DERIVATIVES STRUCTURE AND MOLECULE SURROUNDINGS DEPENDING

ON LUMINESCENT CHARACTERISTICS

E.G. Ermolina1, R.T. Kuznetsova1, R.M. Gadirov1, G.V. Mayer1, Yu.V. Korovin2, N.N. Semenishin2, N.V. Rusakova2

1 - Tomsk State University, Tomsk, Russia

2 - Bogatskiy Physical-Chemical Institute, Odessa, Ukraine yaskolka@inbox.ru

A broad range of cyclotetrapyrrol applications includes oxygen sensors and OLEDs. For these purposes substances with high phosphorescent yield are necessary. Ealier the luminescent properties of some tetraphenylporphyrin (TPP) complexes were studied, essential phosphorescent intensity increasing caused by “heavy ion” introduction is shown. In this paper 10 free bases and metalcomplexes of complexon and Lu(III)-complexonate containing TPP were synthesized and studied in compare with ZnTPP. Co(II), Ni(II), Cu(II) and Zn(II) are central ions. Lu(II) ion introduction has not influence on the absorbance and luminescense spectra location. Free bases absorption contains 4 Q-bands. Absorption of metalcomplexes holds B-band at 420 nm and Q-band at 550 nm. Substitution essential influence on protonation efficacy in basic and excited states is ascertained. Concentration peculiar properties of unfilled d-shell ion (Co(II), Ni(II)) containing complexes in liquid and frozen solutions are poined out. Luminescence spectra location under Q-band excitation slightly depends on metal nature and greatly – on temperature. Luminescence efficacy changes noticeable. Luminescence efficacy from high states under B-band excitation depends on substitution. Long-live radiation of frozen solutions contains concuring with fluorescence location component. It’s life-time two times less than phosphorescence life-time. Phosphorescence efficacy dependence on temperature and oxigen presence is ascertained. Phosphorescence quantum yield and life-time values are estimated. The work is supported by The Russian Foundation for Basic Research ( project 08-02-90003).

102

SPACE RADIATION IMPACT ON PREBIOTIC SYNTHESIS AND STABILITY OF BIOORGANIC MOLECULES: COMPARATIVE STUD Y

N.B. Gontareva, E.A. Kuzicheva

Laboratory of exobiology, Institute of Cytology RAS, S.-Petersburg, Russia

ngontar@mail.cytspb.rssi.ru

Study of space irradiation impact towards main organic molecules is the major task of future space flight experiment, planned for performing onboard Russian space station “Bion-10M”. Our latest investigations were aimed to work out strategy for the full-scale orbital experiment in order to avoid any mistakes and data loss. “Bion-M” experiment covers different aspects of chemical behavior of organic molecules embedded in mineral matrix in water-free conditions as the respond to space radiation. Experimental studies of the possible ways and mechanisms of bioorganic substances (BOS) survival and synthesis in different radiation conditions are closely connected with investigating of prebiotic evolution pathways both at the primitive Earth and other Solar System planetary bodies. Besides, it is important to test whether organics in Earth orbit could be protected by extraterrestrial minerals. This research has been carried out onboard different Russian space stations (Bion, Cosmos and Mir) with various duration, altitude and radiation conditions. In each case the experimental hardware has been displayed on the outer cover of the space stations to experience the impact of the cosmic radiation over molecular samples, free or combined with minerals of the extraterrestrial origin. After retrieval, HPLC analysis, confocal microscopy and mass spectrometry techniques were employed to identify qualitatively and quantitatively the products in reaction mixture. The special emphasis has been given to the stability of the initial molecules (peptides and nucleosides) and their decrease rate as the respond to the harsh orbital conditions. To identify and evaluate the principal source of energy in open space responsible for peptides and nucleotides destruction and synthesis reaction laboratory experiments were performed. Dry films containing aminoacids Gly+Trp, Trp and nucleoside+phosphate were exposed on the outer surface of orbital stations. Identical films were exposed to the different radiation types in laboratory experiments. Different types of energy needed for reaction’s triggering have been investigated in respect with the highest response of biochemical systems. Most destructive and most productive types of energy impact were identified in given radiation conditions. The presence of extraterrestrial minerals (lunar soil, meteorites Allende and Murchison) both in flight and in ground experiments decreased the destructive rate of BOS. Presumably these results favour the protective role of mineral bed from the destructive impact of cosmic radiation. These experiments make important contribution to the problem of life origin and prove the possibility of organic substances’ survival in space conditions. From the other hand, the radiation behavior of BOS on the Earth orbit could have truly applied meaning. For instance, the formation of uridine dimers in the exposed samples could serve as an immediate indicator of the high radiation level (biological dosimeter). This phenomenon was traced in our in-flight experiments and could be utilized during manned missions’ planning in nearest future.

103

INTENSITIES OF IR BANDS OF SURFACE OH GROUPS OR OF THE C-H STRETCHING BANDS OF ADSORBED MOLEQULES – A NEW SPECTRAL CRITERION OF ACTIVATION OF CHEMICAL BONDS

IN HETEROGENEOUS ACID CATALYSIS VIA THEIR POLARIZAT ION

V.B. Kazansky, I.R. Subbotina

IOC RAS vbk@ioc.ac.ru

The low-frequency shifts of IR bands of adsorbed molecules are traditionally used as a spectral criterion of activation of chemical bonds in heterogeneous acid catalysis. In addition in our last works it was suggested to use for this purpose also intensities of IR bands which are connected with polarization of chemical bonds upon their stretching or bending resulting from vibrational excitation. Utilization of this new spectral criterion is most attractive for heterogeneous acid catalysis, where chemical activation of adsorbed molecules just results from their polarization by the active sites. Indeed, it is well known that the extinction coefficients of IR bands are proportional to the squares of derivatives of dipole moments of chemical bonds resulting from their normal vibrations. Interaction of the oscillating dipole moments resulting from stretching or bending vibrations of chemical bonds with IR irradiation just results in its absorption. In this case the vibrational intensities of IR bands correspond to polarization of chemical bonds resulting from their stretching or bending. The same parameters are also involved in reaction coordinates of catalytic transformations of adsorbed molecules. Therefore, if the low-frequency shifts of IR bands are connected with their higher intensities, their weakening just results from their polarization upon interaction with the active sites. The present report presents several examples illustrating utility of this new approach for interpretation of IR spectra of adsorbed molecules. First of them is devoted to using of intensities of IR bands of O-H stretching vibrations as a measure of of their acidity strength [1]. The obtained results indicated that intensities of O-H stretching vibrations of the bridging acidic O-H groups are more than one order of magnitude higher than those of the less acidic silanol groups. Therefore, the acidity strength of Broensted acid sites in zeolites can be measured by OH stretching intensities without generally used application for this purpose of adsorption of weak bases. Another example concerns the study of adsorption of light paraffins by cationic forms of the high silica zeolites. In this case the obtained results indicated the anisotropy of polarization of different C-H vibrations. For the zinc form of ZSM-5 zeolite this results in the very high intensity of the low-frequency shifted band from C-H vibrations indicating strong polarization of this vibrational mode by zinc cations, while at elevated temperature this results in heterolythic dissociative adsorption of light paraffins [2]. REFERENCES

1. V.B.Kazansky, A.I.Serykh, V. Sommer-Herledan, J.Fraissard, PCCP 2003, 966-969. 2. I.R.Subbotina, V.B.Kazansky, Kinetics and Catalysis 2008, v. 49, 149-156.

104

THE EVOLUTION OF PHOTOCHEMICALLY GENERATED RADICAL PAIRS IN GLASSY POLYMERS: RECOMBINATION

FEATURES IN MACROMOLECULAR NANOREACTORS

E.Yu. Khavina, V.B. Ivanov

Institute of Chemical Physics RAS, Moscow, Russia kelizabeth@ya.ru

Radical pairs (RP) formed in photochemical processes with participation of low molecular reagents or chromophore groups are a key intermediate product of free-radical reactions in controlled degradation or modification of polymer materials of important technical application. Therefore, the investigation of the role and features of spin, molecular and chemical dynamics in processes of their evolution is an actual problem. In our work the reaction of recombination of ketyl and aminyl radicals formed during UV-irradiation of glassy polymer films – poly(methyl methacrylate) (PMMA), poly(vinylchloride) (PVC), polystyrene (PS) and cellulose triacetate (CTA) containing aromatic ketones (benzophenone and a number of its p-substituted derivatives) and several aromatic amines (diphenylamine, its derivatives and quinolines of different structure) is studied. It is shown that triarylcarbinols, identified after treatment of irradiated films with HCl by characteristic visible absorption spectra as relevant triarylmethane dyes, are formed as a result of recombination of ketyl and aminyl radicals. Quantum yields of the reactions are determined. It is shown that introduction of strong electron-donor substituents in p-position of ketone, significantly decreasing affinity to electron, leads to a reduction of the RP yield and, as a consequence, the yields of recombination products. The process is found to proceed via ketyl radical attack of aminyl radical in the p-position, thus aromatic amines having substituents in the p-position to amine-group practically do not enter the reaction at all. Sufficient range of recombination quantum yield change in the polymeric glasses studied (by 6 times) witnesses about high sensitivity of this process to the structure and molecular dynamics of the local environment. The reaction only proceeds in local zones of relatively large (≥1nm) size, as is found based on the analysis of quantum yield dependence on amine concentration. These zones may be considered as peculiar nanoreactors. Macromolecular nanoreactors stipulate the presence of essential magnetic-spin effects leading to a significant (by 10-20%) product accumulation rate decrease in PVC and PS as external magnetic field is applied. However, the overwhelming majority of RP is formed in small size zones of molecular diameter value and represents contact RP, so processes of their evolution are not limited by spin dynamics, and the main direction of their transformation is disproportioning with primary reagent regeneration. For these RP magnetic-spin effects are absent. High and durable photochemical post-effects are found to be the important feature of the process proceeding in chlorine-containing polymers (PVC) and in PMMA and CTA films prepared by using chlorine-containing solvent (dichloroethane). A mechanism of significant photochemical post-effect is suggested and kinetic description is proposed. The formation of dye at irradiated film treatment by HCl is diffusion limited. This allows to use the reactions studied in the investigations of both slow and fast diffusion processes in polymers.

105

PHOTOSTIMULATED ELECTRON TRANSFER IN STRUCTURES OF MUTATIONALLY MODIFIED REACTION CENTERS

FROM PHOTOSYNTHETIC BACTERIA

A.I. Kotelnikov1, E.S. Medvedev1, N.S. Goryachev1, A.V. Barinov1, A.A. Stuchebrukhov2, J.M. Ortega3

1 - Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia

2 - Department of Chemistry, University of California, Davis, CA, USA 3 - Instituto de Bioquimica Vegetal y Fotosintesis, Universidad de Seville-CSIC, Seville, Spain

kotel@icp.ac.ru

High efficiency of the photo-stimulated electron transfer (ET) reactions in biological systems including structures of reaction centers attracts attention of numerous investigators. Analysis of the major factors affecting the rate of such reactions is important both in the aspect of basic knowledge and for developing artificial systems of energy storage and conversion. It has been established that ET in biological systems occurs as a chain of successive ET events in protein structures between either metal-containing centers or organic donor-acceptor groups over the distances of 5-25 Å. Studies of the ET reactions in protein structures developed by Nature during Evolution for performing this function can be much more informative than in any other molecular or nanosystem since in proteins mutual arrangements of the donor-acceptor centers and their environments are fully identical, the feature that is difficult to provide in artificial molecular systems. Extensive development of biochemical and molecular genetic methods of protein modification enables to purposely change chemical structures of donor-acceptor complexes and their redox potentials, and to perform site-directed replacements of amino-acid residues along the transfer path or in vicinities of donor-acceptor centers, which influences the most of the physical factors determining the ET rate. In a series of studies experimental and theoretical investigations have been performed of the temperature dependence of kinetics of the photo-stimulated ET between proximal heme c-559 of the cytochrome and the bacteriochlorophyll dimer in native and seven mutationally modified reaction centers (RC) isolated from photosynthetic bacterium Rps. viridis, in which amino acid tyrosine L162 located at the transfer path was replaced by phenylalanine, tryptophan, glycine, methionine, leucine, threonine, or histidine. In frames of a new theoretical model developed on the basis of approximations due to Ovchinnikova, Helman, Sumi and Marcus, the major factors determining the ET kinetics in the temperature range from room to helium temperature, i.e., the matrix element squared, the characteristic frequencies of protein reorganization, and the reorganization energy of the matrix, have been analyzed. The times of dipole relaxation of the matrix and the activation energy of this process have been determined. The results are compared with the data on the protein relaxation dynamics obtained by the methods registering the relaxation shifts of the phosphorescence and fluorescence spectra of the dyes incorporated into the protein structures. The work was supported by RFBR (grant 08-03-00094), the Government of Spain (BFU2007-68107-C02-01/BMC), NSF (PHY 0646273), and NIH (GM54052).

106

LUMINESCENCE TECHNIQUE IN THE STUDY OF BIOLOGICAL PROPERTIES OF FULLERENE BASED HYBRID NANOSTRUCTURES

R.A. Kotelnikova1, D.V. Mishchenko1, D.A. Zhokhova1, A.V. Barinov1,

A.Yu. Rybkin1, N.S. Goryachev1, G.N. Bogdanov1, V.V. Grigoriev2, V.S. Romanova3, A.I. Kotelnikov1

1 - Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia

2 - Institute of Physiologically Active Compounds RAS, Chernogolovka, Russia 3 - Institute of Organoelement Compounds RAS, Moscow, Russia

kotel@icp.ac.ru

A wide spectrum of biological activity of fullerene derivatives (FD) allows them to be considered as potential high active drugs treating many social diseases. An important task is a study of molecular mechanisms of biological action of FD, their effect on structure and functions of the most important enzymatic systems and biological membranes. These tasks are successfully solved using fluorescent and triplet probes. Due to high phosphorescence lifetimes of triplet excited chromophores, sensitivity of triplet probes to dynamic interactions is several orders of magnitude higher than that of conventional fluorescence and ESR methods. It has been shown that amino acid FD are efficient quenchers of triplet probes of eosine, erythrosine and pyrene. Phosphorescence quenching rate constant for erythrosine and delayed annihilation fluorescence rate constant for pyrene, which were built in liposome membranes, were determined. Both phosphorescence and delayed fluorescence were quenched by different FD. The ability of FD to penetrate through a lipid bilayer to the internal volume of liposomes was determined using a triplet probe technique. To study the distribution of FD in animal organs, a luminescent hybrid structure (HS) based on С60-proline and eosine was designed, which is now used to investigate the mechanisms of neuroprotective action of fullerene derivatives. For HS based on Gd@C82 and eosin, both fluorescence and phosphorescence of eosin were fully quenched probably via the excitation or charge transfer mechanism. Since endometallofullerene-eosin bond cleavage results in a sharp increase in fluorescence intensity, this effect provides high sensitivity and allows one to study stability of such hybrid structures in physiological conditions. Biological activity of different types of fullerene based HS is demonstrated on some examples. The work was supported by the Program N27 of Presidium RAS and the Program N9 of Department of Chemistry and Materials Science RAS.

107

PHOTONICS OF SINGLET OXYGEN DIMOLS AND MONOMOLS: RESULTS OF PHOTOCHEMICAL AND LUMINESCENCE STUDIES

A.A. Krasnovsky

A.N. Bach Institute of Biochemistry RAS and M.V. Lomonosov Moscow State University,

Moscow, Russia phoal@mail.ru

The ground state of oxygen molecules is triplet. Upon energy absorption, relatively low-lying oxygen singlet states 1∆g and 1∑g

+ are populated. Interaction of singlet oxygen molecules leads to formation of singlet oxygen dimols (1O2)2. Energy of the lowest 1∆g state is about 1 eV. Energy of the 1∑g

+ state is about 1.6 eV. In dimols due to energy pooling, summation of energy of two singlet oxygen molecules occurs. Luminescence properties of these singlet oxygen species are well known. Absorption properties are studied much worse, because the oxygen absorption bands corresponding to the triplet-singlet transitions are very weak and can be detected only at very high oxygen pressure (100-150 atm.). Recently, we developed a simple photochemical approach to investigation of the absorption bands of dissolved oxygen at normal atmospheric pressure. This method is based on measurement of photooxygenation rates of the 1O2 traps upon direct excitation of oxygen by IR laser radiation. Using this method, we have shown that singlet oxygen is readily formed upon direct excitation of dissolved oxygen by laser radiation at 765, 1064 and 1270 nm in air-saturated organic solvents and aqueous detergent dispersions. The obtained data allowed us to estimate the absorption spectra, optical densities and molar absorption coefficients (ε) of O2 corresponding to these bands. It was shown that the intensities of these bands are markedly different from those obtained at high pressure. Especially strong difference was found when the 1064-nm and 1270-nm bands were compared. The data suggest that absorption of dimols dominates in the reported high pressure spectra. This causes selective up to ≈50-time increase of the 1064-nm band. The spectrum of photosensitized luminescence of singlet oxygen dimols was shown to correlate with this conclusion. The molar absorption coefficients for the 1270-nm absorption band were compared with the rate constants (kr) of the 1O2 radiative deactivation obtained from measurement of photosensitized 1O2 phosphorescence at 1270 nm. It was found that in organic solvents the values of ε and kr correlate. However in aqueous micellar dispersions, ε was 3-6 times higher than kr in water requires. This effect was shown to be partially caused by higher kr and solubility of oxygen in the micellar phase. We plan to discuss contribution to this effect of solvent OH groups and micelle charge and propose an improved diagram of electronic transitions in dimol and monomol molecules. Acknowledgements This work is supported be the grants of the Russian Foundation for Basic Research and the Programs of the Presidium of the Russian Academy of Science. References. 1. Krasnovsky A.A., Ambartzumian R.V., Chem. Phys. Lett., 2004, 400, 531-535. 2. Krasnovsky A.A., Roumbal Ya.V., Ivanov A.V., Ambartzumian R.V. Chem. Phys. Lett.,

2006, 430, 260-264. 3. Krasnovsky A.A., I.V. Kryukov, A.V. Sharkov, Proc. SPIE, 2007, 6535, 65351Q1- Q5. 4. Krasnovsky A.A., J. Photochem. Photobiol. A: Chem. 2008, 196, 210-218. 5. Krasnovsky A.A., Ya.V. Rоumbal, A.A. Strizhakov, Chem. Phys. Lett., 2008, 458, 195-199.

108

DFT MODELLING OF ADENINE STACKING DIMERS IN WATER

I.V. Krauklis, Yu.V. Chizhov, V.L. Rapoport

St.Petersburg State University, Russia Kraukle@yandex.ru

This work is continuation of complex researches on the luminescence and the quantum chemical analysis of stacking aggregates of the bases of nucleic acids [1, 2]. The quantum chemical research included modelling and DFT calculations by the method B3LYP/6-31+G(d) of geometry and electronic characteristics of adenine tautomers (Ade7 and Ade9) and adenine stacking dimers, consisting of Ade7 and Ade9, in aqueous solutions. The account of influence of water solvent was made using the polarizable continuum model (PCM). All calculations were performed with the suite of programs Gaussian03 [3] on HPC-claster at Faculty of Applied Mathematics and Control Processes of Sankt-Petersburg State University. Initial structures of dimers were modelled from the molecule of diadenosine monophosphate (АрА), in which molecules of adenine are in stacking conformation with the interplane distance R = 3.4 Å and the angle of a turn θ = 36° (see fig.1).

Ade9/Ade9

ApA

Fig.1. The scheme of modelling of adenine stacking dimer Ade9/Ade9 from the molecule АрА. Our quantum-chemical calculations confirm existence of energetically favourable stacking dimers of Ade in water (see table 1). All stable in aqueous solution stacking conformers of Ade7 and Ade9 have the interplanar distance R ≈ 3.42 ÷3.49 Å. The stacking dimer Ade9/Ade9 has the greatest difference of full energy ∆Е = -0.284 eV due to connecting of two monomers. The mixed dimers Ade9/Ade7 and Ade7/Ade9 also are stable in water: ∆Е = -0.133 eV and ∆Е = -0.169 eV, correspondingly. Formation of staсking dimer Ade7/Ade7 is doubtful: the difference of full energy at formation is small ∆Е = -0.041 эВ, and the interplanar distance is equal R ≈ 3.67 Å. It is known, that the percentage ratio of tautomers in a water solution makes Ade7: Ade9 = 20 %: 80 %. Therefore the probability of that 1 molecule Ade7 will contact with other molecule Ade7 in eight times less, than probability of collision Ade7 c Ade9.

Table 1. Characteristics of stable in aqueous solution stacking dimers of Ade. Ade9/Ade9 Ade9/Ade7 Ade7/Ade9 Ade7/Ade7

R ≈ 3.49 Å, θ = 36° E = -934.748656 a.u. d = 6.79 D ∆Е = -0.284 eV

R ≈ 3.46 Å, θ = 36° E = -934.740836 a.u. d = 14.40 D ∆Е = -0.133 eV

R ≈ 3.42 Å, θ = 36° E = -934.742169 a.u. d = 10.62 D ∆Е = -0.169 eV

R ≈ 3.67 Å, θ = 36° E = -934.735030 a.u. d = 21.05 D ∆Е = -0.041 eV

[1] Rapoport, V.L., Malkin, V.M. et al. // Doklady Akademii Nauk, 2006, Vol. 406, No. 3, pp.

402-406. [2] Krauklis I.V., Chizhov Yu.V., and Rapoport, V.L. // The monography “Self-organizing of

complex molecules”, under edition prof. Korotkov V.I., St.Petersburg State University, 2008, pp. 128-140.

[3] Gaussian 03, Revision B.05, Frisch M.J., et al. Gaussian, Inc., Pittsburgh PA, 2003.

109

MODELING OF EVOLUTIONARY PRIMITIVE ENERGY CONVERTER AND MOLECULAR DEVICES BASED ON THE ACTIVITY

OF PHOTOEXCITED FLAVINS

M.S. Kritsky

A.N.Bach Institute of Biochemistry RAS, Moscow, Russia mkritsky@inbi.ras.ru

The modeling of biomolecular processes is widely used in analysis of problems of prebiotic evolution and in the design of nanodevices. The present lecture overviews the models based on the activity of isoalloxazine derivatives, flavins, the compounds acting as coenzymes in “dark” biocatalysis and, besides, playing role of photon sensors in proteins. Their excited molecules function in flavoprotein photoenzyme DNA-photolyase as well as in photoregulators of living activities, cryptochromes and LOV- and BLUF-domain containing proteins. When excited, flavin chromophore initiates electron transfer reactions in protein, which lead to catalytic act in photolyase or, in photoregulator proteins, these reactions cause conformational changes in polypeptide thus activating its effector domain. Both electron transfer and the signal transduction cascade are of interest in view of modeling. The experiments mimicking physicochemical conditions of prebiotic Earth have demonstrated abiotic formation and functioning of polymolecular systems consisting of flavoproteinoid pigment molecules aggregated in aqueous medium to form phase separated microspheres. These microspheres are capable to utilize photon energy by converting it into the energy of chemical bonds. Under the influence of short wave visible and the UV-A radiation, isoalloxazine-containing pigment in microspheres sensitizes formation of energy-rich phosphoanhydride bonds in ATP. The phosphorylation mechanism involving free radical reactions of isoalloxazine and ADP has no analogs in modern organisms. Despite its high efficiency (the yield of ATP per ADP mol reached 35 %), such systems could not compete photosynthesis for a role of global converter of solar energy in biosphere, first of all, because of a one order of magnitude lower photon absorptivity of isoalloxazines as compared to porphyrins. In modern biosphere photochemical activity of flavins remained in photoproteins which are involved in adaptation of organisms to environment. These photoactive flavoproteins as well as artificial complexes of flavins with redox proteins are prototypes of molecular devices such as the systems with photocontrolled electron conductivity. Flavin photocatalyst combined with a high potential electron donor is capable to perform a strictly light-dependent injection of electron into redox protein molecule such as multihaem cytochrome, which haem groups differ in their electrode potential values. Supported by Basic Research Program No 15 of the Presidium of Russian Academy of Sciences and grant No 07-04-00460_а from Russian Foundation for Basic Research.

110

ENERGY TRANSFER IN THE MOLECULAR SYSTEMS NEAR DIELECTRIC AND METAL SURFACES

M.G. Kucherenko, T.M. Chmereva, D.A. Kislov

Orenburg State University, Russia

rphys@mail.osu.ru

The electron excitation energy transfer between adsorbed molecules on a solid surface via virtual and real surface excitons is considered. The rate of energy transfer via virtual excitons is calculated analytically. The nonradiative energy transfer to surface impurity centers is considered in the case of rapid migration of 2d-virtual or real excitons leading to repeatedly changed distances between centers of excitation localization. A theoretical model of the kinetics of “surface exciton-T-center” cross annihilation is constructed as a mirror image of the theory of cross annihilation of oxygen- containing objects adapted to a system of quasiparticles. The radiationless energy transfer of the electronic excitation between molecules adsorbed by flat side of a conductor is investigated. It is shown, that the energy transfer with participation of surface plasmons can be the effective mechanism in such system. The distance and angular dependence of the energy transfer rate in the donor-acceptor pair of adsorbates are obtained. Comparative estimates of efficiencies of a direct dipole-dipole and plasmonic channels of energy transfer are yielded. The dominating (exceeding on 2-3 orders of transfer rate in the system without conductors) contribution of the plasmonic mechanism in general energy transfer rate between donor and acceptor molecules near the metal surface is found. However, at dz and

az R≈ , where R - intermolecular distance, efficiencies of distance and plasmonic mechanisms

of the energy transfer become comparable on quantity. At the further removal of molecules from a surface of conductor dz and az R>> the distance mechanism becomes prevailing, and

surface influence is insignificant. Properties of surface plasmons change essential at transition to small metal particles. Analytical expressions for composite matrix elements of the donor-acceptor dipole-dipole interaction, including intermediate plasmonic states are obtained. Estimates of an intermolecular energy transfer rate in the presence of metal nanoparticles are yielded in the approximation of dipole plasma oscillations. The similarity of total expressions for transfer rates are found in the cases of conductor flat side and metal nanoparticle. The yielded estimates of expected effect quantities are used for the preparation of the experimental observation of inductive-resonant energy transfer between organic dye molecules in the metal nanoparticle colloidal solutions. This work was supported by the Russian Foundation for Basic Research (project no. 08-02-99035- r2006_ofi) and the Ministry of Education and Science of the Russian Federation (under assignment no. 1.3.06 from the Federal Agency of Education). 1. Kucherenko M. G., Chmereva T.M. Exciton Energy Transfer between Adsorbates // Physics of the Solid State. 2008. vol. 50. 3. p.531-537. 2. Chmereva T.M., Kucherenko M.G. Plasmon Energy Transfer between Adsorbates // JTP

Letters (to be published).

111

COOPERATIVE PROCESSES OF ANTI-STOCKES LUMINESCENCE EXCITATION IN CRYSTALS

WITH ADSORBED ORGANIC DYE MOLECULES

N.V. Kvashnina, O.V. Ovtchinnikov, A.N. Latyshev, A.F. Klinskikh, M.S. Smirnov, T.I. Suvorova

Voronezh State University, Russia

opt@phys.vsu.ru

Among low-threshold two-quantum processes of exitation of anti-Stockes luminescence processes of sensibilised by organic dye molecules anti-Stockes luminescence (SASL) in AgHal crystals, exited by light streams 10-5–10-9 Vt/сm2 take important place. This phenomenon was explained by V.V. Ovsjankin and F.F. Feofilov alike exitation of SASL in rear earth elements within the bounds of cooperative scheme of adding exitation energy in adsorbed organic dye molecules. But there are still no unique proves of this mechanism and there is no full physical scheme of energy upconversion. In this paper results of investigation of this effect in AgCl, AgCl(I), Zn0.6Cd0.4S crystalls containing adsorbed organic dye molecules of: methylene blue, 1,1’-diethyl-2,2’-hinocianin and 3,3’-di-(γ-sulfopropil) – 9-ethyl-4,5-benzo4’,5’-[4”5”-dimethileno(2”3”)]-tiatiazolocarbocianin-bethaine salt; malachite green are introduced. Samples were both microcrystal poweders and optically homogeneous gelatine matrixcies, containig layers of nanorocrystals. Most important legitimacies are the following: 1) SASL exitation spectrums have the same peak as absorbtion spectrums of monomeres, J-, H-aggregates of organic dyes 2) Hypsochromic shift takes place in case of H-aggregates of organic dyes on the surface of crystals, batochromic shift takes place in case of J-aggregates 3) concentration dependences of peak intensities meaning processes of organic dye molecules aggregation has threshold type – and starts with monomeres concentration, wich is characterised by distances between geometric centeres of molecules about 50–150 Å – by order of Ferster‘s radius 4) with decreasing of average distances between adsorbed molecules up to 45–15 Å aggregation possibility increases and there is alike concentration dependences of SASL intensities 5) creation of energy states of adsorbed atomes

and clusters of metal destroys most of theese legitimacies. The above mentioned legitimacies allowes us to tend to cooperative process of adding of energy of two quantums of simultaneously excited dye molecules. So, the most possible is transfer to crystall of electron exitation energy of two molecules, cumulated in one of them. The adding mechanism could be different from the classical induct-resonance transfer with the fact that irradiate transfer is possible at a point of crossing of system (A*+A*) and (A+A**) terms and goes on like predissosiation prosess. This work is supported by RFFI grant (08-02-00744).

112

THE ROLE OF INTRINSIC POINT DEFECTS IN SPECTRAL SEL F-SENSITIZATION OF WIDE-BANDGAP OXIDE PHOTOCATALYSTS

A.A. Lisachenko

St.Petersburg State University, Russia

lisachen@photonics.phys.spbu.ru

In 1930 years professor Terenin has started the pioneering research on photophysics and photochemistry of adsorbed molecules. Terenin discovered the photoactivated dissociation of adsorbed molecules under UV-irradiation of wide-bandgap oxides. Of special importance was that the spectral region of active light exceeds the bounds of fundamental absorption of nominally pure oxides as well as that of the molecule. Thus only the intrinsic defects (low-coordinated ions, defects in the crystal lattice) might cause the light absorption. This work has been started under his supervision and is followed up to now in his laboratory in the Physical Institute of Leningrad (St.Petersburg) University. Some results of this work are discussed in the present report. In nominally pure oxides light absorption in the region 1 < hν <6 eV may be caused by numerous point defects of varied nature. However the defects of F-type (an oxygen vacancy which captured one or two electrons) and those of V-type (a metal vacancy which captured one or two holes) are of special interest because of their capability to transform the light energy into the chemical one. Various complementary experimental methods such as: mass-spectrometry, thermodesorption spectroscopy, optical (diffusion reflectance), photoluminescence and electron spin resonance spectroscopies, as well as UV (8.43 eV) photoelectron spectroscopy, have been adapted to carry out in situ investigations in three phases: gas, adsorbate and solid state. Single crystals and dispersed powders of nominally pure oxides were irradiated by monochromatic light with the power of 10−3 to 10−1 W/cm2 in the UHV ~10−9 Torr or in a flow of pure gases (H2,O2, CO, NxOy) under a controllable pressure of ~10−8÷10−1 Torr. The primary steps of electron subsystem excitation are the spectral-selective and site-sensitive excitations of point defects accompanied by a charge transfer between the excited states and the valence or the conduction.bands, and terminated by a chemical bonds breaking or/and bonds rearrangements on the surface. Highly active oxygen species are created at a photoactivated oxide surface, allowing to oxidize a number of adsorbed molecules. We have demonstrated that point defects of F, F

+ and V-type can be used for self-sensitization of photocatalysts to a sub-bandgap spectral range on an example of a lot of gas-wide bandgap oxide systems including NOx/Al 2O3 and (NO + CO)/TiO2 systems. The most effective self-sensitization is reached when nanosized 2D-heterostructures are created on the surfaces of photoreduced TiO2 and ZnO. This work was supported by RFBR under grant 09-03-00795-a

113

TRIPLET ENERGY TRANSFER FROM d0 ORGANOMETALLICS TO UNSATURATED HYDROCARBONS:

RECENT RESULTS AND PERSPECTIVES

G.V. Loukova, V.A. Smirnov

Institute of Problems of Chemical Physics RAS gloukova@mail.ru

Triplet – triplet energy transfer (TET) is the most common and important type of energy transfer involved in chemical and biochemical processes. It is known that electron-exchange (Dexter) resonant energy transfer mechanism, responsible for “physical” emission quenching, requires orbital overlap between energy donor and acceptor molecules which is also essential for formation of chemical bonds and can be associated with chemical interactions. Notably, systematic studies of the relationship between the rate constant (effectiveness) of electron-exchange resonant energy transfer and chemical interactions appear to be scarce. Recently, we initiated [1] a systematic study of photophysics of d0 group IV metallocenes, possessing rare highly emissive (for Cp2MCl2 where Cp = C5H5

–, M = Zr and Hf: ΦLUM = 1 at 77K), extremely long-lived (τ in the range of milliseconds at 77 K) ligand-to-metal charge transfer excited states excited states. In this account, we discuss results of our on-going study of electron-exchange resonant energy transfer between d0 organometallic complexes based on Zr(IV) and Hf(IV) as the highly-emissive (phosphorescent) energy donors and unsaturated hydrocarbons (UHC) as the non-phosphorescent energy acceptors, having low-lying triplet state (ЕТ ~ 25000 cm–1), in organic media. In these systems, chromophores Cp2MCl2 (M = Zr, Hf) can be selectively excited. After intersystem crossing with 100 % efficiency, the long-lived state energy of the metal complexes is transferred to UHC, resulting in emission quenching of the metallocene (the efficiency of intermolecular triplet energy transfer was examined by steady-state emission at 77 K). It was established that concentration dependences of the emission quenching efficiency obey the Perrin equation, attributed to electron-exchange resonant mechanism of interaction. It is revealed that arrangement of an unsaturated quencher around a d0 metal complex affects the observed resonant energy transfer efficiency and coordinative interaction. As a principle effect, on the basis of our TET data, we reveal the existence of significant coordinative interaction between the title d0 organometallic complexes and olefins (dienes) and estimate distances at which d0 metallocene – UHC orbital interactions, responsible for electron-exchange energy transfer and inner- and outer-sphere coordination, are effective. The inner-sphere coordinative structures between the energy donors and acceptors, suggested in our TET study, are also revealed by means of density functional theory and ab initio calculations [2]. Steric hindrance and coordination are proposed to account, for instance, for the lack of the phosphorescence quenching with 3,3-dimethylbutene-1 as a low-lying (ЕТ ~ 25000 cm–1) triplet energy trap. Notably, the approach enables studying homogeneous systems with very low – catalytic concentrations of metal complexes (c ≤ 10–4 mol/l) which cannot be achieved by any other conventional physico-chemical methods. Solvent effects on orbital interaction between d0 bent metallocenes and dienes will be for the first time discussed in view of microscopic (structural), rather then macroscopic bulk (polarity, etc.) properties of solvent molecules. These findings provide a new example of TET use for studying intermolecular interactions, in particular, the first example of systematic study of coordination between unsaturated hydrocarbons and d0 π-complexes by the energy transfer approach. The organometallic reactions have proven difficult to be studied by direct measurements, evaluation of rate constants being a historical quest. Accordingly, such a photophysical approach may be promising in the mechanistic study of key stage of organometallic polymerization catalysis: the in situ formation of cationic catalytic species, coordination and following insertion of substrate molecules.

Acknowledgement. The authors gratefully acknowledge Professor A.E. Shilov for stimulating discussion and RFBR (grant N 09-03-00379) and RAS for financial support.

References [1]. G.V. Loukova, S.E. Starodubova, V.A. Smirnov, J.Phys.Chem. A. 2007, 111, 10928; G. V. Loukova,

V. A. Smirnov, Chem. Phys. Lett. 2000, 329, 437; G. V. Loukova, Chem. Phys. Lett. 2002, 353, 244. [2]. G.V. Loukova, A.A. Milov, V.A. Smirnov, 2009, submitted.

114

SENSIBILIZED ANTI-STOCKES LUMINESCENCE MECHANISM IN CRYSTALLS WITH ADSORBED METALORGANIC

NANOSTRUCTURES

O.V. Ovtchinnikov, T.I. Suvorova, N.V. Kvashnina, M.S. Smirnov, A.N. Latyshev, D.A. Minakov, V.A. Shulgin

Voronezh state university, Russia

opt@phys.vsu.ru

In variety of investigations an effect of sensibilised anti-Stockes luminescence (SASL) intensity enhancement in AgHal-crystals and solid solutions of Zn0.6Cd0.4S with adsorbed organic dye molecules caused by creation of small atomic Ag-clusters on the surface both caused by low-temperature photostimulated process (LTPSP) and adsorbtion from solution was found. It was shown, that the SASL excitation center consists of adsorbed organic dye molecule and a Ag-cluster, and exitation has two-quantum type. But the abcense of data about interaction type between components of the SASL exitation center doesn’t let find a final exitation mechanism of this radiation. In this paper the results of experiments on space parting of Ag-claster and organic dye molecules adsorbed to AgCl(I) by a gelatine layer is introduced. The equipment consists of standart optical connector and two quarz fibres. Laser radiation KLM-H-650-40-5 (λmax=650 nm, Pmax = 40 mVt) were submit to input wave guide. Radiation flow was 1020quantum/(с*сm2) at output of first wave guide. Sample was put into an optical connector between input and output wave guides. Radiation was detected by PEE -79 with optical filter BGB-22.

Legitimacies of SUCL intensity of exhibition time, 77K, λ=650nm, Р=5mVt, 1- AgCl(I) crystalls, 2- AgCl(I) crystalls and gelatine layer with MB; and with Ag-clasters, created during synthesis: 3 - AgCl(I) crystalls, 4- AgCl(I) crystalls and gelatine layer with MB

SASL value of pure crystals could be explained by adsorbed Ag-clasters of biography nature. SASL intensity changed unmonotoneously during exhibition of sample with pure crystals and sample consisting of two gelatine layers – one with methylene blue (MB) molecules, second with AgCl(I) crystals. SASL intensity of an integrate sample is higher than one without organic dye molecules. Sensibilization of SASL radiation by LTPSP products started earlier and went faster for an integrate sample than for pure crystals. For long exhibition times SASL attained saturation, then decay part was observed. It was confirmed for AgCl(I) crystals, the surface of which had a significant concentration of Ag-clusters during synthesis. Finally, SASL excitation center consists of adsorbed organic dye molecule and a Ag-cluster. Bind between them is weak, but it is enough for electron excitation energy transfer from organic dye molecules to Ag-cluster and for its following photoionization. The gelatine molecule interferes electron transfer.

115

LUMINESCENCE STUDY OF STABLE STACKING AGGREGATES OF NITRIC BASES OF NUCLEIC ACIDS – THE CANDIDATES

FOR ROLE OF FIRST GENETIC TEMPLATES

V.L. Rapoport, V.M. Malkin, I.V. Krauklis, E.A. Maslova, V.V. Goriuchko

V.A. Fock Institute of Physics, St.Petersburg State University, Russia victor.rapoport@paloma.spbu.ru

It is generally believed that the world of RNA was preceded by simpler organic replicative systems. The nature of RNA precursors remains unknown. By luminescence spectroscopy methods we have revealed stable stacking dimers and other stacking aggregates of nitric bases of nucleic acids in water which may be interpreted as precursors of RNA molecules in chemical evolution (proto-RNA) and first genetic templates [1, 2]. Their luminescence spectra have maxima at 400–600 nm and excitation spectra have exciton splitting 3000–4000 cm-1. It was shown that stacking dimers don’t dissociate even at 85ºC. This unusual stability may be explained by ions and water bridges between two molecules in dimer. The propose about ion bridges was confirmed by the quantum chemistry calculations (DFT/B3LYP method) of the system: stacking dimer of adenine and 2-3 Na+ ions which gave stabilization energy ~ 2 eV. Replication mechanism of stable stacking aggregates without any ferments based on consecutive rises and falls of temperature (1–25 ºC) is discussed [1]. It consists of two phases. At low temperature (1–4 ºC) a new stacking dimer, e.g. of adenine, is formed from two monomers on stacking dimer of uracyl (thymine). At temperature rise to 25ºC the two stacking dimers sever one from another and a new stacking dimer of adenine appears in solution. This mechanism of replication of stable stacking dimers and other aggregates was confirmed in luminescence study of mixed water solutions of adenine and uracyl (thymine). At cooling of adenine+uracyl mixed solutions from 40 to 1 ºC the anomalous fall of luminescence intensity of adenine stacking aggregates was observed, that was explained by forming of H-bond between adenine and uracyl. At temperature rise from 1 to 40 ºC for the same mixed solution the anomalous rise of luminescence intensity of adenine stacking aggregates was observed due to dissociation of H-bonds. At cyclic temperature rises and falls (4–40 ºC) of adenine+uracyl mixed solution the rise of luminescence intensity level of adenine stacking aggregates at 4ºC was observed that confirms the proposed replication mechanism of stable stacking aggregates of nitric bases. 1. V.L. Rapoport, V.M. Malkin, S.V. Zorina, S.M. Komarov, V.V. Goryuchko. Luminescence

detection of tightly bound stacking aggregates of adenine and adenosine in aqueous solutions – the candidates for the role of the first genetic templates. Dokl. Akad. Nauk, 2006, Vol. 406, No. 3, pp. 402-406.

2. V.L. Rapoport, V.M. Malkin, N.A. Bykov, V.V. Goryuchko. Origin and evolution of biosphere. Edited by Acad. E.M. Galimov. Moscow, 2008, pp. 169–178.

This study was fulfilled at financial support of Program no.18 of Presidium of RAS.

116

FTIR STUDY OF POROUS ICE FILMS

A.V. Rudakova, I.L. Marinov, A.A. Tsyganenko

V.A. Fock Institute of Physics, St.Petersburg State University, Russia arudakova@mail.ru

Processes on icy particles attract much attention due to importance for atmospheric science, ecology and astrophysics. In this work, adsorption and reactions of some molecules on pure and mixed water icy films have been investigated by means of FTIR spectroscopy. The cell for spectral studies of adsorbed molecules at variable temperatures (55-370 K)1 was equipped with a device for water vapour sputtering from the heated capillaries and deposition onto the inner ZnSe windows of the cell, cooled by liquid nitrogen. Lower temperatures were obtained by pumping off evaporating nitrogen from the coolant volume. The estimated specific surface area of freshly deposited at 77 K water ice film was about 160 m2/g and decreases on raising the temperature together with the diminishing intensity of the bands of dangling OH (OD) groups at 3696 (2727) cm-1 until the latter disappear at 130 – 160 K when the changes of bulk absorption provide evidence for a phase transition from amorphous to polycrystalline ice. CO adsorption at 77 K results in two bands at 2153 and 2137 cm-1 assigned to molecules forming weak H-bond with the dangling hydroxyl groups or bound to unsaturated surface oxygen atoms, respectively2. The band of dangling hydroxyl groups moves to lower wavenumbers at adsorption of different molecules (hydrogen, nitrogen, methane, ozone, NO, ethane or chlorinated ethenes, etc.) Besides this shift, spectra of adsorbed N2, CO and methane registered at 55 K reveal absorption intensity decrease at ~ 2650 cm-1 at the high-frequency slope of bulk absorption, and increase at about 25 cm-1 below. This new effect we interpret as a strengthening of H-bonds between surface water molecules, which act as adsorption sites either as proton-donor or as a donor of the lone pair of electrons. Spectra HCN/D2O and ND3/D2O mixed icy films with low (1:10) dopant/water ratios do not manifest any changes in the acidic or basic properties of dangling hydroxyl groups or surface oxygen atoms, but reveal a difference in the proportion between concentrations of these sites comparing with pure water ice. For high dopant concentrations (1:1) the dangling hydroxyls were not observed, the dominant adsorption sites for CO are likely to be the unsaturated oxygen atoms, while serious structural changes occur in the bulk of ices. Ecologically important reactions like ozonolysis of chlorinated ethenes or hydrogen cyanide at 77 – 200 K, as well as the influence of UV radiation on this process have been studied. Ozone co-adsorption with C2H3Cl at 77 K readily leads to ozonolysis reaction, while for the C2H2Cl2 isomers it starts only at 120–150 К. Ozone co-adsorption with HCN in the dark does not lead to any noticeable spectral changes. However, UV irradiation of this system results in the appearance of new bands revealing the formation of ozonolysis products. Spectral dependence of photo-ozonolysis of HCN at 77 K has shown that photodissociation of ozone, evidently, accounts for the observed process. The above results, thus, show that the surface of ice particles plays the role of a condenser of atmospheric pollutants and acts as a micro-photoreactor in the atmosphere. Acknowledgments. The work was supported by INTAS (grant 03-51-5698) and RFBR (06-03-32836a). 1. Otero Areán С., et al. Eur. J. Inorg. Chem. 2001. No 7. 1739. 2. Rudakova A.V., et al. Langmuir. 2009. V. 25. 3. P. 1482-1487.

117

THE PRODUCTS AND MECHANISMS OF PHOTOCHEMICAL TRANSFORMATION OF O-QUINONES

M.P. Shurygina, Yu.A. Kurskii, N.O. Druzhkov, S.A. Chesnokov, G.A. Abakumov

G.A. Razuvaev Institute of Organometallic Chemistry RAS, Nizhnii Novgorod, Russia

sch@iomc.ras.ru

It is known that o-quinones undergo various photochemical transformations upon irradiation which have theoretical and important practical interest. In this work we report about systematic investigation of kinetics and products of photodecarbonylation of o-benzoquinones (DBQ) and photoreduction of DBQ and 9,10-phenantrenequinone (PQ) in the presence of different hydrogen donors (DH). The kinetics and products of photodecarbonylation of the series of 4,5-di-substituted 3,6-di-tert-butyl-o-benzoquinones upon irradiation by visible light (λ>520 nm) was investigated. NMR monitoring of photolysis of quinones detected that it is a two-stage process. On the first stage the photoexcited molecule of quinone rearranges into bicyclo-compound containing three- and five- membered cycles which spontaneously decomposes during the following dark stage into 3,4-disubstituted 2,5-di-tert-butyl-cyclopentadienon and a molecule of CO.

O

OO

O

- CO OR R R

hν

The kinetics and products of photoreduction of the series of 4-substituted 3,6-di-tert-butyl-o-benzoquinones and PQ in the presence of para-substituted N,N-dimethylanilines and polymethylbenzenes upon irradiation with light λ>500 nm was investigated too. It was established that photoreduction of both o-benzoquinones and 9,10-phenantrenequinone occurs through common mechanism of products formation. NMR-monitoring detected that first stage of process is formation of product with uniform structure (I) – corresponding phenolether.

O

O

OH

O D

OH

OH

OH

O

D+hυ ; ;R R R

DHR

D

I II III It was discovered that stability of phenolethers is determined by both redox characteristics and structure of o-quinone and H-donor. Phenolethers formed in the reaction with DBQ decompose through heterolysis mechanism into corresponding catecholes (II ) and different amines during dark reaction. The phenolethers which were formed by photoreaction of PQ with N,N-dimethylanilines undergo rearrangement to give corresponding ketols (III ) during dark process. Phenolethers – derivatives of PQ and polymethylbenzenes convert only under irradiation and in the presence of second molecule of PQ to form ketols. Acknowledgments: This work was supported by the Russian Foundation for Basic Research (grant no 07-03-00711, 08-03-12090-ofi, 08-03-97055-r_povolzj’ye_a) and Russian President Grant supporting Scientific Schools (NSh-4182.2008.3).

118

MESO-SUBSTITUTED POLYMETHINE DYES AS EFFICIENT SPECTRAL-FLUORESCENT PROBES FOR BIOMACROMOLECULES

A.S. Tatikolov, T.M. Akimkin, A.S. Kashin

N.M. Emanuel Institute of Biochemical Physics RAS, Moscow, Russia

tatikolov@sky.chph.ras.ru

A search of simple and convenient methods for the study of biological objects, in particular, the use of dye probes, is of importance for investigative and experimental purposes. Our task is to find dyes that can serve as spectral-fluorescent probes for various biomacromolecules in the analysis and the study of biological systems. Meso- (or 9-) substituted polymethine dyes can serves as such probes. For unsubstituted polymethine dyes the cis-isomer usually has higher energy than the trans-isomer, and the trans-cis equilibrium is shifted toward the trans-isomer. For meso-substituted polymethine dyes the energies of the trans- and cis-isomers can be comparable due to steric hindrances, the trans-cis equilibrium becomes movable and is shifted toward one or another side depending of the medium. This makes meso-substituted polymethine dyes promising for application as spectral-fluorescent probes for biomacromolecules. We used one of such dyes, 3,3’-di(sulfopropyl)-4,5,4’,5’-dibenzo-9-ethylthiacarbocyanine betaine, whose interaction with biomolecules we studied earlier [1, 2], as a probe for analysis of the extracellular media of the human eye and the eye of some animals for albumin and collagens. We also studied the interaction of the other meso-substituted polymethine dye, 3,3’-di(sulfopropyl)-9-methylthiacarbocyanine betaine, with human and bovine serum albumins and showed that this dye can serve as a spectral-fluorescent probe for serum albumins. We studied the noncovalent interaction of a number of squarylium dyes (which can be considered as polymehtine dyes with a meso-substituent) with serum albumins of various animals and found that one of these dyes can also serve as a probe for serum albumins. The interaction of 3,3’,9-trimethylthiacarbocyanine with DNA was studied by us in detail; it was shown that the dye forms with DNA fluorescent complexes of two types: intercalation and minor groove complexes. The binding constants and the binding numbers were determined for both types of the complexes. It was also found that the dye interacts with hyaluronic acid to form H-aggregates on its molecules. Thus, meso-substituted polymethine dyes can serve as efficient spectral-fluorescent probes for various biomacromolecules in studies of biological objects. The work was supported by the Russian Foundation for Basic Research (project 09-04-01054a). References:

1. A.S. Tatikolov, S.M.B. Costa. Complexation of polymethine dyes with human serum albumin: a spectroscopic study. Biophys. Chem. 2004. V. 152. P. 33–49.

2. A.S. Tatikolov, I.G. Panova. A spectroscopic study on the interaction of polymethine dyes with collagens. High Energy Chem. 2005. V. 39. No. 4. P. 232–236.

119

PHOTOACTIVATED TEMPLATES IN PREBIOTIC EVOLUTION PROCESSES

T.A. Telegina, M.P. Kolesnikov, Yu.L. Vechtomova, M.S. Kritsky

A.N. Bach Institute of Biochemistry RAS, Moscow, Russia

telegina@inbi.ras.ru

According to present views, numerous processes in prebiotic evolution were mediated by mineral and organic templates. These templates ensured local concentration and spatial orientation of reactive molecules, isolate them from aqueous environment and also perform catalytic function. The templates themselves were subjected to evolution, which finally led to formation of a perfect mechanism based on self-replicating polynucleotides, which direct a structure of protein catalysts. The template-mediated processes were a source of ATP and other chemically activated nucleotide derivatives for early metabolism, and transformation of free energy in these systems is a important aspect of their evolution. The main way of energy supply for abiogenic template syntheses of organic matter was a direct activation of their reaction centers by heat and solar light. Mineral templates can drive light-dependent processes, which result in a formation of molecules of various level of complexity. We have shown that mineral templates containing semiconductor metal oxides (TiO2, Fe2O3, etc.), when subjected to UV-irradiation were capable to photoreduce molecular nitrogen to ammonia and, in presence of acetaldehyde, sensitize a formation of amino acids – glycine, alanine and serine. The energized particles of clay mineral, montmorillonite, were shown to catalyze formation of pyrophosphate and phosphoanhydride bonds in nucleotide coenzymes ATP and FAD. Complication of organic molecules in process of chemical evolution was accompanied by co-evolution of the templates driving transformation of these molecules. According to our data, the UV-irradiated aqueous solution of acetaldehyde and ammonium nitrate accumulated amino acids, pyruvic acid and indoles, and, besides, melanoidin structures. The presence of these structures, in turn, had ensured that amino acids condensed in water environment and formed peptides. In addition, melanoidin templates demonstrated catalytic activities mimicking the activity of some redox enzymes (alcohol dehydrogenase, lactate dehydrogenase). Transition from mineral templates to organic matrixes has expanded their capacities as photosensitizers and permitted chemical evolution to utilize solar photons of visible area for a synthesis of chemically activated metabolites. Thermolysis of amino acids mixtures results in a formation of abiogenic pigmented polymers (flavoproteinoids), which aggregate to form microspheres. These flavin-containing structures were shown to conserve energy of photons of both blue and the UV area into the energy-rich bonds of ATP. The yield of ATP reached 30 % per mol of ADP and the quantum efficiency of the process was ca. 20%. Some functions of canonic templates could be mimicked in chemical evolution by physicochemical situations formally not falling into a category of templates, but still manifesting some their properties. For instance, highly concentrated solutions and the melts of organic molecules, mimick the concentration effect and ensure water-free conditions of templates. As an example, abiogenic formation of AMP from aspartate, glutamine, glycine, formate, carbonate and orthophosphate in ribose melt will be discussed. Supported by Basic Research Program No 15 of the Presidium of Russian Academy of Sciences and grant No 07-04-00460_а from Russian Foundation for Basic Research.

120

ADVANCES IN SPECTRAL STUDIES OF SURFACE PHENOMENA

A.A. Tsyganenko

V.A. Fock Institute of Physics, St.Petersburg State University, Russia tsyg@photonics.phys.spbu.ru

The paper deals with the advances of FTIR spectroscopy for the studies of lateral interaction between adsorbed molecules, changes of site strength caused by the interactions, linkage isomerism of surface species and explanation of the above phenomena in the electrostatic approach. The strength of sites depends dramatically on surface coverage. Strong repulsive inter-action on oxides can stop adsorption when only a part of sites are occupied1. The observed strength of acid sites diminishes due to the static effect, whose mechanism includes relaxation induced by adsorption2, while the dynamic coupling shifts the bands and changes their shapes. Co-adsorption of weak acids with basic molecules demonstrates the effect of induced Bronsted acidity3, when the presence of SO2 or NO2 leads to protonation of bases (NH3, pyridine or 2,5-dimethylpyridine) even on silica, Increase of electron-accepting properties of surface cations caused by adsorbed acids, as well as basicity induced by co-adsorbed bases were also detected4. Spectroscopy at variable temperatures broadens the list of molecules used for acid site testing, which includes now CO, NO or H2 that do not adsorb at 300 K. Low-temperature adsorption of weak CH proton-donating molecules such as acetylene, CHF3, HCN enables one to characterize the strength of surface electron-donating sites. Recently it was shown that CO reveals linkage isomerism and forms with surface cations both C-bonded and O-bonded complexes. The latter has the frequency lowered with respect to the gas phase5 and coexists in thermodynamic equilibrium with the usual C-bonded form. Having the energy considerably higher, this form of adsorption can be considered as “sterically activated” state, which could act as intermediate in catalytic reactions6. Surface isomeric states were established for some other adsorbed species, such as cyanide ion CN- produced by HCN dissociation. The existence of linkage isomerism can be explained by a simple electrostatic model7. Besides the linear configurations with positively charged sites, the model predicts formation of side-on complexes of CO and N2 with surface anions8. Strong interaction of CO with the most basic oxygen sites of a number of oxides leads finally to the formation of ‘carbonite’ CO2

2- ion9. Spectra evolution with temperature provides information on the mechanism of surface reactions illustrated by CO or thiophene-d2 isotopic scrambling over CaO10. Quantitative analysis of adsorption sites needs the knowledge of absorption coefficients. Both quantum chemistry and electrostatic approach predict the correlation between the frequency shifts on adsorption and the integrated absorption coefficients. For CO the latter decreases when the frequency grows on interaction with the cations, but increases for O-bonded species with lowered C-O stretching frequency, in a fair agreement with the theory11. References: [1] Tsyganenko A.A., Denisenko L.A., Zverev S.M., Filimonov V.N. J.Catalysis, 94 (1985), 10. [2] Tsyganenko A.A., Zverev S.M. React. Kinet. Catal. Lett., 36 (1988), 269. [3] Tsyganenko A.A., et al. Catal. Letters, 70 (2000), 159. [4] Storozheva E.N., Sekushin V.N., Tsyganenko A.A. Catal.Letters. 107 (2006), 185. [5] Otero Areán C., Turnes Palomino G., Tsyganenko A.A., Garrone E. Intern. J.Mol.Sci., 3 (2002), 764. [6] Tsyganenko A.A., Storozhev P.Yu., Otero Areán C. Kinet. Catalysis, 45 (2004), 530. [7] Storozhev P.Yu., et al. Appl. Surface Sci., 238 (2004), 390. [8] Tsyganenko A.A., Kondratieva E.V., Yanko V.S., Storozhev P.Yu. J. Mater. Chem., 16 (2006), 2358. [9] Babaeva M.A., Bystrov D.S., Kovalgin A.Yu., Tsyganenko A.A. J. Catal. 123 (1990), 396. [10] Tsyganenko A.A., Can F., Maugé F. J. Phys. Chem. B, 107 (2003), 8578. [11] Kondratieva E.V., Manoilova O.V., Tsyganenko A.A. Kinetics and Catalysis, 49 (2008), 451.

121

POSTERS

BACTERIORHODOPSIN-CONTAINING MULTILAYER STRUCTURES AS A MEDIUM FOR BIOMOLECULAR NEURONET DEVICES

OF PHOTONICS

G.E. Adamov, D.A. Adamova, E.P. Grebennikov, V.R. Kurbangaleev

OJSC CSRIT Technomash, Russian Federation, Moscow ntc_technology@socket.ru

Due to constant development of nanotechnologies and functional nanomaterials used in information systems researchers need to look for new ideas and radically new constructive solutions to ensure efficient device operation, record-breaking high speed and integration of elements. On the other hand, functional elements being formed in nanometer range require landmark approaches. It refers especially to formation of information-logical devices at molecular level. The techno-systematic problem is the necessity to use “macro-nano” and “nano-macro” interfaces to put in the original information and deduce final results. The advantages of the small-size molecular elements can’t help to ensure access to them. Probably the only effective way to arrange the bonding with molecular system is to use optical interaction. The solution seems to be connected with hierarchic structural and functional self-organization of molecular systems that is with using assemblies of molecules as a basis of molecular information-logical appliances. The techno-systematic approaches aimed at implementation of biomolecular neural network appliances based on multilayer polymeric photochromic structure are detailed to describe. Mentioned below biological material – Bacteriorhodopsin protein – has unique technological potential and its optical properties allow the use of optical input-output devices and create molecular appliances based on self- organization principles. The optimization and enhancement of functional parameters of multilayer structures by, first, using additional nanostructuring of molecular media, and, second, by introduction of new functional elements – hybrid nanostructures (making it possible to further realize a new class of optical information systems based on self-organizing oscillatory and auto wave hierarchical processes in BR-containing nanocomposites) are suggested.

122

PROTONATION EFFECT AND SPECTRAL PROPERTIES OF PHOTOCHROMIC COMPOUNDS

A.O. Ait, V.A. Barachevsky, A.M. Gorelik, O.I. Kobeleva

Photochemistry Center RAS, Moscow, Russia

ait@photonics.ru

The hypsochromic shift for solutions of spiropyranes and spirooxazines in comparison with chromen’s batochromic shift under irradiate of UV light in presence of protonic acid will be discussed. The influence of subtitutes on spectral properties has been investegated. For example, the solution of 3,3-diphenyl-3H-naphto[2,1-b]pyran in acetonitril under UV irradiation in absence of acid has λ max 435 nm and λ max 610 nm in presence of perchloric acid (Fig. 1). The solution of 1`,3`-dihydro-1`-phenyl-3`,3`-dimethyl-6-nitro-8-methoxyspyro[2H-1-benzopyran-2,2`-(2Н)-indole] (Fig.2) has opposite effect - λ max 580 nm and 420 nm accordingly.

Fig.1. Absorption spectra of solution of 3,3-diphenyl-3H-naphto[2,1-b]pyran in acetonitril under UV irradiation in absence of acid (1) and in presence (2) of perchloric acid

Fig.2. Absorption spectra of solution of `,3`-dihydro-1`-phenyl-3`,3`-dimethyl-6-nitro-8-methoxyspyro[2H-1-benzopyran-2,2`-(2Н)-indole] under UV irradiation in absence of acid (1) and in presence (2) of perchloric acid

The accomplished molecular modeling with using of semi-empirical quantum-chemical methods showed that such shifts of the absorption bands are connected with the various length of the conjugated chain of the protonic and unprotonic forms for chromenes, on the one hand, and spiropyranes and spirooxazines on the other.

123

SPECTRAL-FLUORESCENT STUDY OF THE INTERACTION OF THE POLYMETHINE DYE CY2 WITH DNA AND HYALURONIC ACID

T.M. Akimkin1, A.S. Tatikolov1, S.M. Yarmoluk2

1 – N.M. Emanuel Institute of Biochemical Physics RAS, Moscow, Russia

2 - Institute of Molecular Biology and Genetics NASU, Kyiv, Ukraine tatikolov@sky.chph.ras.ru

Recently a number of works concerning polymethine (cyanine) dyes have covered the studies of their noncovalent interaction with DNA and proteins. In those works it was suggested to use some polymethine dyes as fluorescent probes for biopolymers. In our work we studied the interaction of one of such dyes, 3,3’,9-trimethylthiacarbocyanine (Cy2), with DNA. Combined measurements of the absorption and fluorescence spectra of the Cy2–DNA system were performed within a wide range of DNA concentrations. The growth of the dye fluorescence quantum yield caused by the increase of the DNA concentration in the solution was simulated mathematically. While simulating, we assumed two types of dye–DNA binding: intercalation and minor groove binding. The binding constant and the binding number were determined by computer fitting of the experimental data with a simulation curve. The interaction of Cy2 with hyaluronic acid is also studied in this work. Hyaluronic acid is a basic component of the extracellular matrix of organisms, such as synovial fluid, liquid media of the eye etc.; therefore, a search of dye probes for hyaluronic acid is of current importance. We measured the absorption spectra of Cy2 in the presence of hyaluronic acid at different pH of the medium. As the hyaluronic acid concentration increased, we observed an appearance of short-wavelength bands in the absorption spectrum and a growth of their intensity, due to the formation of H-aggregates of Cy2 on hyaluronic acid molecules. Using the decomposition of the absorption spectra into several Gauss components, we studied changes in the intensities of the separate bands of the aggregates as the hyaluronic acid concentration increased. We concluded that Cy2 can serve as a spectral probe not only for DNA, but also for hyaluronic acid in biological systems. The work was supported by the Russian Foundation for Basic Research (project 09-04-01054a).

124

DFT SIMULATION OF PHOTOCATALYTIC NO REDUCTION BY СО ON Ti8O16 NANOCLUSTER

A.S. Andreev, Yu.V. Chizhov

V.A. Fock Institute of Physics, St.Petersburg State University, Russia

yurichizhov@yandex.ru

Titanium dioxide is well known as one of the best photocatalyst to decompose many of the environmentally hazardous substances. Many photocatalytic properties of titanium dioxide are related to the existence of surface oxygen vacancy (surface F-centers). We regard (TiO2)n clusters as a model of that isolated structured defects on surface TiO2 bulk. In this work, the simulation of the catalytic reaction 2NO + 2CO → N2 + 2CO2 (1) on the stable full optimized Ti8O16 cluster was performed. The calculations were done using the DFT method with B3PW91 functional. Hay and Wadt pseudopontential for Ti atoms was used and for light atoms was applied 6-31G basis. The simulation of reaction (1) was carried out in a few steps: Ti7O15-Ti 4+O → Ti7O15-Ti 3+ + O(3P) (2a) Ti7O15-Ti 4+O + CO → Ti7O15-Ti 3+-OCO (2b) Ti7O15-Ti 3+ + 2NO → Ti7O15-Ti 4+O2N2 (3) Ti7O15- Ti4+O2N2 + CO → Ti7O15-Ti 4+O + N2↑ + CO2 (4) An oxygen vacancy can be obtained due to direct removal the oxygen atom (2a) or interaction with CO (2b). Reaction (2a): According to the calculations for the removal of oxygen atom is necessary to expend 5.96 eV of energy. As a result reduced cluster Ti7O15-Ti 3+ is created. The electronic structure of optimized Ti7O15-Ti 3+ shows well developed band structure with single electronic band gap defect state strongly localized on Ti 3+. Reaction (2b): Adsorption of CO on the Ti 4+O leads to the formation of adsorption complex Ti7O15-Ti 3+-OCO with bond-lengths R(Ti 3+-O) = 2.13 A, R(O-CO) = 1.192 A, R(OC-O) = 1.170 A, what indicates the formation a CO2 molecule. Energy of CO2 desorption is 0.94 eV, i.e. in order to take a reduced Ti7O15-Ti 3+ cluster during the reaction (2b) is necessary an additional energy to expend. According to the experimental work [1] CO2 was desorbed upon heating the TiO2 sample. Reaction (3): Adsorption of 2 molecules of NO on the Ti 3+ leads to the formation of the stable adsorption complex Ti7O15-Ti 4+O2N2 with bond-lengths R(Ti 4+-O) = 1.88 A, R(N-O) = 1.41 A, R (N-N) = 1.27 A in the symmetric planar chelate cycle Ti 4+O2N2. The N-O bonds are strongly weakened as compared with free NO molecule. Reaction (4) is a key reaction. Calculations showed that the approach of a CO molecule to the adsorption complex Ti7O15-Ti 4+O2N2 leads to formation free N2 molecule and weakly adsorbed CO2 molecule with a desorption energy of 0.27 eV. The reaction takes place with release of 4.57 eV of energy. After desorption of CO2 titanium dioxide cluster returns to its original oxidized Ti7O15-Ti 4+O form, thus the catalytic cycle of reaction (1) is closed. Thus the reaction of catalytic NO reduction by CO on Ti8O16 nanocluster may take place in 3 phases. It appears that the photoexcitation is necessary only in the reactions (2a) and (2b), in which costs of energy is required. The all main results of the calculations are in agreement with experimental data [1]. [1] Andrei A. Lisachenko, Ruslan V. Mikhailov, Lev L. Basov, Boris N. Shelimov and Michel Che, Photocatalytic Reduction of NO by CO on Titanium Dioxide under Visible Light Irradiation, J.Phys. Chem. C, 2007, 111(39), 14440-14447

125

RELAXATION OF HIGH-LYING EXITED ELECTRONIC STATES OF POLYPYRIDYL RU(II) COMPLEXES AND ITS RELATION TO

SYMMETRY OF MOLECULAR STRUCTURE AND/OR ENVIRONMENT

E.S. Artemyeva, S.V. Litke

V.A. Fock Institute of Physics, St.Petersburg State University, Russia SVLitke@yandex.ru

Polypyridyl ruthenium(II) complexes are of great interest in the study of exited state redox and sensitization processes due to the low-lying metal-to-ligand charge transfer (MLCT) exited states with high luminescence efficiency and long lifetimes. Owing to these properties the complexes have many applications in such fields as luminescent sensors, photocatalysis, light-emitting diodes (LEDs), photovoltaic devices and so on. Photochemical stability of polypyridyl Ru(II) complexes depend on location of metal-based 3dd – states whose population result in weakening of metal – ligand bond down to ligand loss. A process of thermal excitation of 3dd – states from low-lying 3MLCT – state(s) at elevated temperatures is at present the commonly accepted model. We assume that another path of 3dd – states population exists along with thermal excitation, namely, a direct population of the states during relaxation of high-lying exited electronic states of complexes. In the course of this study homo- and heteroleptic mononuclear ruthenium(II) complexes have been investigated in solution and in adsorbed state by optical absorption and luminescent spectroscopy. Absorption, excitation luminescence and diffuse scattering spectra, as well as luminescence quantum yields under UV and Vis excitation were measured. It was found that absorption and excitation luminescence (active absorption) spectra of homoleptic complexes in solution were coincided to one another for the most part whereas those of heteroleptic complexes were different. Also the differences of the spectra were revealed for homoleptic complexes adsorbed on a surface of amorphous silica i.e. in heterogeneous environment. These observations were confirmed by measurements of luminescence quantum yields of the complexes under excitation in UV absorption band near 290 nm (caused by intraligand, IL transitions) and in Vis absorption band near 450 nm (caused by MLCT transitions). The probable mechanism of 3dd – states population and its relation to symmetry of complexes and/or environment are discussed.

126

2D-STRUCTURE EVIDENCE ON THE SURFACE OF SELF-SENSITIZED ZnO PHOTOCATALYST

L.L. Basov, A.A. Lisachenko

V.A. Fock Institute of Physics, St.Petersburg State University, Russia

lisachen@photonics.phys.spbu.ru

ZnO is one of widely used photocatalysts in environmental catalysis. While the value of its bandgap is as high as 3.2 eV and the fundamental absorption lies in UV it exhibits high photocatalytical activity in visible region. The charge transfer theory of photocatalysis considers the photoactivated system as being a three-dimensional one. Electron-hole pairs created during the band-to-band transitions, photoionisation of impurities or structural defects are extracted to the surface. The energy transfer distance is of the order of diffusion length. In such model the photocatalytical activity depend on crystal electrophysical parameters - Fermi level, surface band bending, work function. In another limiting case the effect is considered to be connected with the local surface centers. The excitation in this case includes a charge transfer inside the surface structure. The effect depends only slightly on surface potential value (if at all). A lot of complementary experimental methods such as: mass-spectrometry, thermodesorption spectroscopy, optical (diffusion reflectance), photoluminescence and electron spin resonance spectroscopies, as well as UV (8.43 eV) photoelectron spectroscopy, contact potential difference, photoelectromotive force have been adapted to carry out in situ investigations in three phases: gas, adsorbate and solid state. The failure of the charge transfer three-dimensional model has been suggested. Indeed, 1) a spectral maximum of photocatalysis was observed in the spectral region of sub-bandgap absorption, the value of the initial quantum yield can approach to 1.0; 2) a "memory effect" (relaxation times up to 104 s) was found in photoactivated processes; 3) the illumination in the spectral region of sub-bandgap absorption is not accompanied by a surface charge transfer into the bulk; 4) the adsorption of molecules of the gas phase is not accompanied by an observable change of the surface potential; 5) the intensity of the photoeffect and even its sign (photoadsorption ↔ photodesorption) can be changed when very little number of surface local centers was created without shifting the Fermi level nor the band bending value. Thus, the density of surface centers is rather high, they interact between themselves, but their interaction with the bulk of the crystal is weak and the system can be considered as a two-dimensional one. This work was supported by RFBR under grant 09-03-00795-a

127

PHOTOPHYSICAL PROCESSES IN CATIONS OF THIACARBOCYANINE DIMERS

O.K. Bazyl, V.Ya. Artyukhov, G.V. Mayer

Tomsk State University, Russia

okbazyl@rambler.ru

The excited electronic states and rate constants of photophysical processes in thiacarbocyanine cation dimers (D13) are calculated by the semiempirical method of intermediate neglect of the differential overlap with special spectroscopic parameterization [1]. A “sandwich” structure with a parallel (D13-1) and an antiparallel (D13-2) orientation of the short axes of the molecules forming a dimer is worked out. The spacing between the molecular planes in the dimer is taken to be 3.5 Å. The results of calculations are compared with the experimental data on dimers in [2]. The dimer conformations D13-1 and D13-2 produce similar spectra. Analysis of the nature of MO forming the S1 and S2 dimer states and comparison of their nature with that of the S1 monomer state show that the first two electron states in dimers are a split S1 monomer state. In so doing, the electron transition to the S1(ππ*) state from the ground one becomes either forbidden (D13-1) or weakly allowed (D13-2), with the intensity of the second transition of the dimer being much higher than that of the first transition in the monomer. According to the calculation, the intensity of the long-wavelength band in dimers forms the S0→ S2(ππ*) transition whose energy and intensity are higher than those of the S0→S1(ππ*) transition forming a long-wavelength band in the monomer absorption spectrum. The experimentally observed maximum of the long-wavelength dimer absorption band [2] is close to the energy of the calculated S0→ S2(ππ*) transition. According to the data reported in [2], thiacarbocyanine dimers exhibit low fluorescence an it is masked by the monomer fluorescence of higher intensity, the quantum yield of dimer fluorescence ranges between 0.021 and 0. 0003, and low radiation capacity is believed to be due to forbiddenness of the radiative transition and high efficiency of the ST-conversion in dimers as compared with monomers. The calculations of rate constants of photophysical processes in dimers show that the formation of dimers significantly affects the energy level diagram of the excited electronic states of the monomer. In dimers with parallel and antiparallel arrangements of the short axes of its constituent molecules, the rate constant of the radiative decay of the fluorescent state (kr) is decreased by a factor of 2-4 depending on the orientation of dimer molecules relative to each other. As for the efficiency of the processes of internal (kic) conversion and singlet-triplet (kST) intersystem crossing, both nonradiative processes show a two-threefold increase in the efficiency at the most. However, despite such a pronounced increase in the efficiency of the singlet-triplet crossing, this nonradiative process in D13-1 and D13-2 dimers is less efficient than the radiative decay and internal conversion, and affects the quantum fluorescence yield but slightly. In so doing, the value of the rate constant of these nonradiative processes depends on the dimer structure. Internal conversion is the process suppressing fluorescence in D13-1 and D13-2 dimers, which lends no support to the assumption [2] of a significant quantum yield of intersystem crossing in dimers as compared with monomers. The calculations show that the ST-conversion in dimers is 2-3 orders of magnitude higher than that in monomers, yet, this nonradiative process will not be determining in the fluorescence quenching (kr ≈ 104 - 106, kic ≈ 108 - 109, kST ≈ 104 - 106 s -1). References 1. V. Ya. Artyukhov and A. I. Galeeva. Izv. Vyssh.Uchebn. Zaved., Fiz.. 1986. 11. P. 96. 2. A. K. Chibisov. Khim. Vys. Energ. 2007. V.41. No. 3. P. 239.

128

THE STRUCTURE AND PHOTOPHYSICAL PROCESSES IN SYMMETRIC POLYMETHINE DYES

O.K. Bazyl1, V.Ya. Artyukhov1, V.A. Svetlichnyi1, A.A. Ishchenko2

1 - Tomsk State University, Russia 2 - Institute of Organic Chemistry NAS, Ukraine

okbazyl@rambler.ru

Polymethine dyes (PDs), owing to a great variety of their spectral-luminescent prorerties, are widely used in various fields of science and engineering. For a targeted search for PDs with desired properties, it is necessary to know relations between their electronic structure and intramolecular photophysical processes of deactivation of the energy excited electronic states. However, such processes have not yet been studied theoretically based on quantum-chemical calculations. The quantum-chemical semiempirical method of intermediate neglect of differential overlap with special parametrization were calculated the electronic structure, energies of exited electronic states and the rate constants of photophysical processes in isolated the cationics of molecules of vinylogous series of indocarbocyanine 1-5.

N N

CH3

CH3H3C

CH3

H3C CH3

nBF4

Figure. Structural formulas of symmetric cationic indopolycarbocyanine dyes 1-5: n=1(PD1), 2 (PD 2), 3 (PD 3), 4 (PD 4) and 5 (PD 5).

Influence of structural factors (length of polymethine chain (PC), output from the molecular plane the PC carbon atoms or the end fragments (EFs)) was investigated on the rate constants of photophysical processes. The calculations show, what the lengthening PC in the polymethine series of 1-5 leades to decrease the radiative decay rate constant ( kr) of a fluorescent state less than twofold. A more pronounced decrease in kr occurs with displacement of EFs or PC carbon atoms from the molecular plane. However, in these cases, kr also decreases only by several times rather than by an order of magnitude. The lengthening PC in the polymethine series of 1-5 decreased the S1→S0 transition energy, this the internal conversion rate constant (kic) increases by almost two orders of magnitude. The magnitude of kic is nearly independent of the displacement of individual atoms or fragments from the chromophore plane. The calculation of the singlet-triplet crossing rate constant (kST ) show that the appreciable deactivation of a fluorescent state along the this channel take place only if the planarity of the molecule is disturbed. However, the rate constant kST be little even if its structure is nonplanar, which agrees well with experimentally data. With increasing PC length on efficiency of singlet-triplet crossing begin iflyencend the interaction between the fluorescent state and the T2(ππ*)state, spin-orbit interaction with which is appreciable more than with T1(ππ*) state. The analysis of efficiency of photophysical processes and the calculation of the quantum yields of the fluorescence show, that intramolecular photophysical processes cannot be responsible for the difference between the calculated and measured fluorescence quantum yield in the polymethine of 1- 5. Under the experimental conditions, these molecules must have additional channels of the fluorescent state degradation. The comparison of the calculated and measured fluorescence quantum yields allow suppose that most probably, the main processes competing with the fluorescence of PDs are the photoisomerization for PD 1 and the energy transfer to the oxygen singlet (or solvent) for PDs 4 and PDs 5. In molecules 2 and 3 processes of deactivation on named channels are minimum.

This study was supported by the Russian Foundation for Basic Research (project no. 07-02-00155-a).

129

SHORT AND LONG-RANGE ORDER EFFECT ON RESONANCE ENERGY TRANSFER

E.N. Bodunov

Physics Department of St.Petersburg State Transport University, Russia

evgeny.bodunov@inbox.ru

The theory of luminescence quenching in fluids and solids due to resonance energy transfer (RET) from energy donors (excited molecules) to energy acceptors (quenchers), starting with the pioneering studies by Förster and Dexter, is based on the assumption that molecules are point particles homogeneously distributed in the medium. In this case, the radial distribution function of molecules g(r) does not depend on the distance r between the particles and is equal to unity for 0 < r < ∞, i.e., quenchers are homogeneously and independently distributed around an excited molecule. In later investigations, a distance of closest approach was introduced, and the radial distribution function was modeled by the unit step function. In fact, the radial distribution function is more complicated function of distance than step function. In crystals, there is a long-range order. On the other hand, in liquid and molecular glasses, and even in the absence of coulomb or van der Waals potential, a short-range order exists owing simply to the finite size of the molecules, and the radial distribution function has the shape of damped oscillations. In this report, the luminescence decay law resulting from quenching by RET is investigated and the hard-sphere fluid model is used to take into account the short-range order of media. In polar media, donors and acceptors can exist as cations and anions. Therefore, the long-range coulomb interactions (electrostatic repulsion and attraction of donors and acceptors) are also taken into account.

130

THE LIQUID CRYSTAL COMPOSITES CONTAINING AN IMPURITY OF FLUORESCENT CdSe NANORODS

V.V. Danilov1, A.V. Baranov2, G.K. Elyashevich3, A.O. Orlova2,

N.A. Utkina1, A.I. Khrebtov1

1 - Research Corporation “S.I. Vavilov State Optical Institute”, St.Petersburg, Russia 2 - St.Petersburg State University of Information Technologies, Mechanics and Optics, Russia

3 - Institute of Macromolecular Compounds RAS, St.Petersburg, Russia vdanilov@hotbox.ru

For the first time the fluorescence of quantum rods (QRs) CdSe in liquid crystal (LC) composites on the basis of cyanobiphenyls is investigated. As one would expect, the fluorescence of QRs CdSe in LC cells is strongly polarized, however the degree of polarization has the negative value connected with volumetric orientation QRs. Obviously, this orientation is also responsible for the lower absolute values of the degree of polarization in the QRs band in comparison with the degree of polarization of the matrix fluorescence. The found effect of solubilizer molecules on the orientation of s opens new possibilities for developing controlled multilayer LC cells. For the first time are received LC composites containing QR CdSe on the basis of nanostructered porous polythene films. The presented spectral data testify to a high degree of polarization of QR fluorescence, which speaks about alignment properties of stretched polythene films. Introduction the impurity LC composites in porous polymer allows to reduce sharply coagulation of rods CdSe

131

INVESTIGATION OF SPECTRAL PROPERTIES OF ISOXAZOLE DERIVATIVES CONTAINED PHOTOCHROMIC LABEL

O.V. Demina1, A.V. Laptev2, N.E. Belikov2, A.Yu. Lukin2,

R.V. Zemtsov2, S.D. Varfolomeev1, A.A. Khodonov2

1 - N.M. Emanuel Institute of Biochemical Physics RAS, Moscow, Russia 2 - M.V. Lomonosov State Academy of Fine Chemical Technology, Moscow, Russia

ovd@sky.chph.ras.ru

The investigation of the regulation of ligand–receptor or ligand–enzyme interactions by the usage of organic compounds with photochromic labels on the subcellular or molecular levels is one of the significant tasks of bionanophotonics and nanomedicine. The search of new effective variants of the direct regulation of the human hemostasis system definite stages is the important medicine problem, because the mortality from cardio-vascular diseases takes first place in the world. It was shown by us that a number of 3,5-substituted isoxazoles were potent anti-aggregatory compounds [1,2]. A few 3,5-substituted isoxazole analogs (1,2) contained photochromic label - spiropyran moiety at 3-position of isoxazole ring were synthesized by us for the determination of molecule pharmacophoric fragment detail structure and the investigation of the action mechanism of this class compounds. Photochromic properties of synthesized compounds were investigated by spectral-kinetic methods.

N O

NO2

NO

R

(1) R= CH2OH

(2) R= C6H5 This work was partly supported by RFBR grants (projects 09-04-01003 and 09-03-00565). References 1. O.V. Demina, A.A. Khodonov, V.I. Shvets, S.D. Varfolomeev. Aggregation of human

platelets: molecular – kinetic mechanisms and the paths of their regulation. // Biological membranes (Rus.) (2002), 10(2), pp. 115-152.

2. O.V. Demina, P.V. Vrzhesch, A.A. Khodonov, V.I. Kozlovsky, S.D. Varfolomeev. Synthesis of new inhibitors of platelet aggregation – substituted pyridyl isoxazoles and their 4,5-dihydro analogs. // Bioorganic Chem. (Rus.) (1995), 21(12), pp. 933-940.

132

HETEROGENEOUS PHOTOCATALYSIS BY ZIN С PHTHALOCYANINE DERIVATIVES FOR PHENOLS OXIDATION

T.M. Fedorova, E.G. Petrova, V.M. Derkacheva, A.V. Butenin, O.L. Kaliya

Organic Intermediates and Dyes Institute, Moscow, Russia

fedorova-tm@yandex.ru

Water-soluble and immobilized on Amberlite IRA 400 phthalocyanine derivatives are known to be active sensitizers for phenol and chlorophenols phototransformation by singlet oxygen [1] as well as for photodynamic therapy of cancer [2]. We had used substituted PcZn for photooxidation of 1,5-dihydroxynaphthalene to 5-hydroxy-1,4-naphthoquinone (juglone) [3]. Heterogeneous photosensitizers have some advantages over the soluble ones. They are more stable in many cases, can easily be separated from reaction solution and reused. The preliminary results of phenol photooxidation by dioxygen in alkaline solution in the presence of substituted PcZn immobilized on carrier by equilibrium adsorption are presented in this report. The adsorption isotherm has been received and treated in coordinates BET. Photochemical oxidation was carried out in the glass reactor surrounded by a water jacket (to keep the content cool) at permanent stirring and dioxygen bubbling through the mixture. The visible light source was a 150 W halogen lamp with cutoff filter to remove irradiation with wavelenghts less than 450 nm. The reaction was monitored by reverse phase HPLC. It has been found that phenol conversion is influenced by the nature of carrier (SiO2, modified SiO2, Al2O3, Amberlite) and substituents (PhS, PhSO2, t-Bu) in PcZn molecule as well as by the amount of immobilized PcZn. Phenol conversion has run 95% in 120 min irradiation for the most active heterogeneous photocatalyst. The last one was stable during six cycles. As expected phenol photooxidation efficacy has been increased in D2O (lifetime 1O2 in D2O more than in H2O) and decreased in NaN3 (physical quencher of 1O2) solution. These experiments demonstrate that singlet oxygen is involved in the photoreaction. Quantum yield for phenol oxidation (φPhOH) and quantum yield of 1O2 with heterogeneous and homogeneous photosensitizer (φ∆) have been determined with using laser as irradiation source (671 nm). The value of φPhOH has been calculated from the initial linear part of the kinetic curve phenol expenditure at initial [PhOH]=5·10-4M in according to the known relationship [4]. The relative method with known sensitizers as reference and chemical trap was used to estimate φ∆ [4]. References

1. Wöhrle D., Kaneko M., Nagai K., Gerdes R., Suvorova O. (2008) Environmental cleaning by molecular photocatalysis (in Molecular Catalysis for Energy Conversion, Eds. T. Okada, M. Kaneko), Springer Series in Material Science, 263-298.

2. Kaliya O., Lukyanets E., Vorozhtsov G. (1999). Catalysis and photocatalysis by phthalocyanines for technology, ecology and medicine, Journal of Porphyrins and Phthalocyanines, 3, 592-610.

3. The method of 5-hydroxy-1,4-naphthoquinone preparation. Inventors certificate USSR 1559649 (1987).

4. Ozoemena K., Kuznetsova N., Nyokong T. (2001). Photosensitized transformation of 4-chlorophenol in the presence of aggregated and non-aggregated metallophthalocyanines, Journal of Photochemistry and Photobiology, 139, 217-224.

133

SPECTRAL-LUMINESCENT AND LASING PROPERTIES OF THE SOME SUBSTITUTED OF COUMARIN

R.M. Gadirov, T.N. Kopylova, L.G. Samsonova, S.Yu. Nikonov, A.G. Logis

Tomsk State University, Russia

grm882@kvadro.net

The substituted coumarins are used as laser dyes in the blue-green spectral range. In addition, these compounds have also found application in industry, medicine, biochemistry and other fields of science and engineering. First of all such variety in application are explained by their spectral-luminescent properties. The derivatives of 7-aminocoumarin are wide studied because their high quantum yields and lasing ability, but substituted 7-hydroxicoumarines are still little studied. In present work we present the results of experimental and theoretical studies of two coumarin derivatives: ether of furoic acid and 3-(4-(benzo[1,3]dioxolyl-5)thiazolyl-2)-7-hydroxycoumarine (I ) and 3-methylthiazolyl-7-hydroxycoumarine (II ). The interest to these compounds is aroused by that fact that compound II has high fluorescence quantum yield but it lasing ability is low because of strong absorption from excited triplet states which lies in fluorescence spectral range. We used this compound as test object in numerical simulation of the generation dynamics. Compound I has similar structure and differs by substitute in thiazolyl fragment. But the spectral-luminescent properties of these compounds very different. Compound I has low quiantum yield in polar solvents, but at temperature of liquid nitrogen the building-up of fluorescence is observed. Quantum-chemical investigation show that the reason of such behavior of compound II may be out of plain of whole substituent in 3-rd position.

134

NEW RADICAL MECHANISM OF PORPHYRIN PHOTOSENSITIZED DESTRUCTION OF BIOLOGICAL MEMBRANES

V.V. Gurinovich1, A.V. Vorobey2, M.P. Tsvirko3

1 - Department of Physics, Belarussian State University, Minsk, Belarus

2 - Institute of Biophysics and Cell Engineering NAS, Minsk, Belarus 3 - National SRC for Ozone Monitoring, Belarussian State University,

Minsk, Belarus gurinovich@bsu.by

The opportunity of formation the photochemical generator of cytotoxic radicals in biological membranes was investigated. Such generator is based on electron transfer from excited porphyrin molecule to halogenmethan when both molecules are injected into membrane. Zinc complexes of porphyrins possessing relatively low oxidation potentials – hydrophobic Zn-tetraphenilporphyn (Zn-TPP) and positively charged Zn-5,10,15,20-tetrakis(4-N- methylpyridyl)porphyrin (Zn-TMPP) were used as photosensitizers, carbon tetrachloride (CCl4) and bromoform (CHBr3) – as acceptors. Cytotoxicity of radicals formed was estimated by lipid peroxidation and destruction in protein tryptophanyls of isolated erythrocyte membranes. Photoinduced reactions were investigated immediately after model irradiation by visible light (halogen lamp, 150 W). Destruction of tryptophanyls of membrane proteins and porphyrin sensitizers included in membranes was registered by chromophores fluorescence. Upon illumination of membranes containing porphyrins by visible light, tryptophanyls destruction and photooxidation of lipids photosensitized by porphyrins are observed. In the presence of CCl4 or CHBr3 the yield of photosensitized tryptophanyls destruction increases approximately twice. Halogenmethans also drastically (approximately 7 times for Zn-TMPP and twice for Zn-TPP) increase a photosensitized lipid peroxidation. Experiments with a singlet oxygen quencher – sodium azide have shown, that azide in concentration 2 mM reduce (2,5 times) an efficiency of tryptophanyls photodestruction in the absence of halogenmethans. At the same time azide does not render inhibiting influence on tryptophanyls photodestruction and lipid peroxidation at presence of CCl4. It evidence that photosensitized by halogenmethans destruction of membrane components proceed without participation of singlet oxygen. It is essential that photodestruction of tryptophanyls sensitized by Zn-TMPP is noticeably greater than that sensitized by Zn-TPP. At the same time photosensitized by Zn-TMPP lipid peroxidation approximately three times less than in case of Zn-TPP. These results match with representation that Zn-TPP is localized preferentially in lipid bilayer while Zn-TMPP – close to membrane protein. This implies that the destructive activity of radicals formed, as well as singlet oxygen has the expressed local character, i.e. these radicals are highly reactionable. The data obtained evidence about an opportunity of formation of donor-acceptor systems in cellular membranes on the basis of porphyrins and halogenmethans, realizing photoinduced electron transfer from singlet-excited sensitizer molecules to acceptor molecules. Halogenmethan radicals formed exhibit high effectiveness in destruction effect on main membrane components – proteins and lipids.

135

METHOD OF NONDESTRUCTIVE READ-OUT OF INFORMATION

K. Japaridze, L. Devadze, D. Maisuradze, N. Sepashvili

Institute of Cybernetics, Tbilisi, Georgia devadze2005@yahoo.com

The serious factor limiting an opportunity of application of spiropyrans as switches and environments of record and storing of information in molecular computers, is destruction of photochromic material at multiple record and partial deleting at reading the information. Process of record is a transformation from one to the second thermodynamical stable state. Reading is based on definition of spectral characteristics. At reading, i.e. definition in a maximum of optical density of absorption band, there is a partial deleting of the written down information. The purpose of the presented work is attempt to prevent destruction during record and partial deleting at reading the information. To avoid deleting of the information at record, usually it is possible by means of matrixes where photochromic transformation is accompanied by changes which can be detected without destruction of the written down information. In our case such environment had appeared liquid-crystalline smectogenic mixture of cholesteryl oleate and cholesteryl pelargonate with definite ratio. The composition consists of liquid-crystalline matrix and spiropyran as dopant (1-4% by weight). The system is characterized by a red shift of Bragg reflection i.e. dλ/dt < 0. Under certain conditions, near transition temperature in a smectic phase («the boundary state»), dλ/dt changes a sign (hysochromic shift), half-width of a corresponding band is narrowed and sharply intensity increases.

Fig1. Temperature dependence of Bragg reflection band at formation of "a boundary state". (D – an apparent optical density): (1-3) cholesteric phase, (3-8) formation of "a boundary state" (t = (1) 31, (2) 30, and (3-8) 29°C).

We assume that in a liquid-crystalline composition at presence of molecules of spiropyran с there is a special organization of system. At photoinduction, change of geometrical characteristics of a molecule influences on the organization of system, that in turn is exhibited in reflection. Wavelength at which «the boundary state» is formed depends on concentration of spiropyran. The decreasing of concentration causes bathochromic shift of band. Therefore, reading by means of Bragg reflection band, instead of in a maximum of absorption, will provide preservation of the written down information without loss.

136

INVESTIGATION OF THE PHOTOCHROMIC BEHAVIOUR OF THE RETINAL PROTEIN CHROMOPHORE MODELS

A.A. Khodonov1, A.V. Laptev1, A.Yu. Lukin1, N.E. Belikov1,

R.V. Zemtsov1, K.V. Zvezdin1, V.I. Shvets1, V.A. Barachevsky2, S.D. Varfolomeev3, O.V. Demina3

1 - M.V. Lomonosov State Academy of Fine Chemical Technology, Moscow, Russia

2 - Photochemistry Center RAS, Moscow, Russia 3 - N.M. Emanuel Institute of Biochemical Physics RAS, Moscow, Russia

khodretinal@sky.chph.ras.ru

Retinoids (vitamin A derivatives) play a key role in the functional processes in the natural light-transforming systems based on retinal proteins – bacteriorhodopsin, halorhodopsin, visual rhodopsin, sensoric rhodopsin, retinochrome and other. The isomerisation of definite double bond takes place during light quantum absorption, and this act initiates cascade of events, which is necessary for the generation of definite type physiological or chemical signals. Nowadays, bacteriorhodopsin is one of the simplest, well-known light-converter systems. This membrane protein was discovered in Halobacterium salinarum in 1971, and it functions as a light-driven proton pump. The polypeptide part (bacterioopsin) consists of a sole peptide chain, and the chromophore group is a protonated Schiff base of retinal with ε-amino group Lys-216. Our approach to the retinal proteins structure-function investigation includes replacement of the natural chromophore (retinal) by its analogs and complex study of their properties [1]. We proposed an effective synthetic route for the preparation of new retinal protein chromophore models - polyenic compounds related to Vitamin A aldehyde (retinal) (1). These polyenes (2-5) possess photochromic fragment – diarylethene or spiropyran moiety instead of the trimethylcyclohexenic ring in its molecule. The key steps of proposed synthetic route involved the Horner-Emmons olefination procedure of carbonyl precursor with the usage of С5-phosphonate and reduction of intermediate nitrile to the polyenal by DIBAL. Spectral and photochemical properties for the new retinal analogs in solution are discussed.

1

2

3

CHO

S

S

FF

FF

FF

CHO

S

S

FF

FF

FF

CHO

4

5 N O NO2

OHCN O NO2

OHC

This work was partly supported by RFBR grants (projects 09-03-00565 and 09-04-01003). References 1) Khodonov, A.A.; Eremin, S.V.; Lokshin, J.L.; Shvets, V.I.; Demina, O.V.; Khitrina, L.V.; A.D. Kaulen, Bioorg. Khim. (Rus), 1996, 22, N10-11, 745-776.

137

INTERACTION OF CYCLOTETRAPYRROL COMPOUNDS WITH NANOPOROUS XEROGELS AND OPTICAL RADIATION

OF DIFFERENT INTENSITY

R.T. Kuznetsova1, E.G. Ermolina1, E.N. Telminov1, G.V. Mayer1, S.M. Arabei2, T.A. Pavich3, K.N. Solovyov3, I.P. Kalashnikova4, S.S. Ivanova5

1 - Tomsk State University, Russia

2 - Belorussian State Agricultural Technical University 3 - B.I. Stepanov Physics Institute NAS, Minsk, Belarus

4 - Institute of Physiological Active Compounds RAS, Chernogolovka, Russia 5 - Ivanovo State University of Chemical Technology, Russia

kuznetrt@phys.tsu.ru

The task-oriented applications of organic molecules and their complexes with metals on the modern technologies for creation of different optical devices: sensors, nonlinear switches and limiters of power pulse radiation, solid electroluminescent layers and solar concentrators [1] demand of researches of correlations of optical characteristics with molecular structure and solid matrices architecture where organic molecules are incorporated. The features of interactions of tetrapyrroles with surface of pinholes of xerogels with different chemical structure are discussed on the base of investigations of spectral-luminescent, acid-base, photochemical and nonlinear-optical properties in solutions and solid matrices. The subjects of investigations were: tetraazaporphyns and their metallocomplexes, aminoderivatives of tetraphenylporphynes with coordinated Lu, complexes of phthalocyanines and bisphthalocyanines with lanthanides also. These compounds were studied in liquid and frozen solutions of ethanol, chloroform, DMSO and solid nanoporous xerogels with different chemical structure under laser excitation by differ wave length (308, 532 nm) and intensity (3-300 MW/cm2). It was established, that all studied solutions and solid samples with incorporated tetrapyrroles decrease the transmission of power nanosecond pulses compared with linear transmission on the same wave length. It was specified by absorption of triplet-excited molecules and their photocations which formed at the expense of ion-neutral shift under excitation. The efficiency of ionic forms formation at the ground and electron-excited states and phototransformations quantum yields of researched compounds were determined. The mechanism of photocations participations at the tetrapyrrol compounds phototransformations is discussed. It is shown that proton’s phototransfer from solvent and hydroxyl groups on the surface of pinholes of silica matrix (TEOS) to the protonoacceptor centers of tetrapyrroles is intensified compared with liquid solutions. The charachteristics of long-lived emission (ms) of some tetrapyrroles having a heavy atoms at the structure, depending on solvent temperature and dissolved oxygen occurrence were investigated. The capability of applications of investigated compounds as limiters of power pulse laser emission, phosphorescent thin layers, optical sensors for determination of oxygen occurrence and small quantities of acids is discussed. Researches are supported by RFBR (grant 08-02-90003-Bel_a) 1. Evans R., Douglas P., Winscom Ch. // Coord. Chem. Rev. 2006. V. 250. P. 2093.

138

THE INVESTIGATION OF THE NO PHOTOADSORPTION IN CO PRESENCE ON TiO2 HOMBIFINE N BY MEANS OF

KINETIC MASS-SPECTROMETRY AND THERMO-PROGRAMMED DESORPTION SPECTROSCOPY

D.V. Laptenkov, R.V. Mikhaylov

St.Petersburg State University, Russia

ruslan@photonics.phys.spbu.ru

Titanium dioxide is widely used as photocatalyst in environmental catalysis, because it is highly active in degrading many organic and inorganic pollutants, is resistant to photocorrosion and, at the same time, is biologically and chemically inert and is of low cost. Earlier we had shown that the photoreaction CO+NO+hν → N2 + CO2 (1) on TiO2 under irradiation in visible range takes place [1] due to the light absorption by surface and/or bulk structure defects (oxygen vacancies, Ti3+ ions)[2]. The course of the reaction (1) was divided into two stages [1]. The first stage is characterized by a decrease in NO concentration to nearly zero, appearance of N2O and formation of N2 (~5-8 % of NO) after the light was switched on. The second stage is characterized by a decrease in CO and N2O pressures in the gas phase and by an increase in N2 pressure up to approximately one half of the initial NO pressure. CO2 was found to remain on the surface. The mechanism of reaction was proposed [1]. The aim of the present work was to investigate the kinetic features and adsorbed phase composition forming during of the first stage (NO photoadsorption) of reaction (1) on TiO2 Hombifine N at various initial CO : NO ratios by means of kinetic mass-spectrometry and thermo-programmed desorption spectroscopy (TPD). The powder TiO2 Hombifine N (S = 320 m2/g) was chosen as a photocatalyst. The setup for mass-spectrometric measurements in the course of kinetic runs under static conditions and TPD measurements was described previously [1]. A quartz reactor (16x35x3,5 mm3) filled with powder TiO2 was used. The reactor was supplied with furnace allowing a linear heating and high-temperature treatment of sample. A monopole mass spectrometer APDM-1 allowed one to scan up to 50 selected mass peaks within the range 12–100 a.m.u. The experimental results were obtained at pressures of gas mixtures 0.01 – 0.5 Torr and were corrected for gas sampling for analysis. High-purity (99.9%) O2, NO, and 13CO (75% of 13C) were used. The samples were exposed to visible radiation (λ >400 nm) of a high-pressure mercury lamp (DRT-120) supplied with a water filter and a set of standard glass color filters (LOMO, Russia). Photon fluxes were measured with a calibrated photocell F-17. The heating rate in all TPD measurements was 15 K/min. TiO2 samples were preliminarily heated at 870 K for 3 h in oxygen at a pressure of 0.5 Torr. Then, partially reduced samples were obtained by heating the pretreated material under UHV conditions at 870 K. It is found that reaction (1) takes place under visible light irradiation (λ >400 nm) on TiO2 Hombifine N. The first stage is characterized just by a decrease in NO concentration to nearly zero after the light was switched on. The kinetic of NO photoadsorption depends on the CO amounts in reactor indicating the transitional photoinduced processes of electron-type sites formation occurring on the TiO2 surface in CO presence. The analysis of adsorbed phase composition after reaction first stage by means of TPD reveals the desorption of CO (weakly bonded), N2O, NO and CO2. Basing on TPD results the dependences of NO:N2O:CO2 ratios on initial NO and CO amounts were obtained. This work was supported by RFBR under grant 09-03-00795-a. 1. A.A. Lisachenko, R.V. Mikhailov, L.L. Basov, B.N. Shelimov, M. Che, J. Phys. Chem. C, 2007,

v. 111. p. 14440. 2. Lisachenko, A.A.; Kuznetsov, V.N.; Zakharov, M.N.; Mikhailov, R.V., Kinet. Catal. 2004, 45,

189.

139

DIFFUSE REFLECTANCE SPECTROSCOPY FOR INVESTIGATION OF GAS-SURFACE INTERACTIONS ON WIDE-BANDGAP OXIDES

A.A. Lisachenko

St.Petersburg State University, Russia

lisachen@photonics.phys.spbu.ru

A.N. Terenin was the first who had pioneered in 1930th the program of experimental investigations of gas-surface interactions using the diffuse reflectance spectroscopy (DRS) in UV-Vis-IR regions. This work was started under Terenin’s supervision and is followed in his laboratory in the Physical Institute of Leningrad (St.Petersburg) State University up to now. Some results of this work are discussed in the present report. The dispersed powders of samples were investigated. In many works of Terenin's disciples the vibrational spectra in the IR region are analyzed. These spectra are often well resolved and they are characteristic for the adsorbed species structure. Another case is the electron excitation spectra that occupy the UV-Vis region. The numerous absorption bands are broad and weakly resolved. Two types of problems are studied using DRS: 1) The "Albedo" definition. For this for non-transparent samples the total reflected radiation integrated over a hemisphere is measured. The absolute reflectance values are usually obtained compared to an absolute reflectance of a standard. The remitted fraction of the incident radiation flux, being always less than 1, is called "Albedo". 2) Another direction founded by A.N. Terenin consisted in the use of DRS for the investigations of gas-surface interactions. The photometric procedure is based on the different reflectance spectra before and after interaction. Since very complex processes are involved in the scattering transmission and remission, so in practice DRS is used rather for qualitative investigations than for quantitative ones. The two processes form a total remitted light flux. In the first one the reflected light Rdiff originates in the interior of a powder as a result of multiple back light scattering. For a non-transparent sample R∞diff is a function of the ratio K/S and not of the individual values of absorption "K" and scattering "S". Both are non-linearly and in different manner depending on wavelength and a particles size. In this case the increase of "K" entails the decrease of R∞diff in accordance with the Kubelka-Munk theory. Another term Rreg of remitted flux is formed by a regular reflection from the surface according to the Fresnel-Beer law and is determined by the values or refractive "n" and absorption "K" indexes. This term increases if "K" increases. Thus the two processes work against one another and determine in common the spectral composition of the remitted radiation. If the measuring irradiation causes a fluorescence in an absorption band of the sample, all the fluorescence radiation is included in the measured remitted radiation. In such instances another monochromator must be used for the remitted radiation. The indicated problems are illustrated by real experimental spectra of gas-wide-bandgap oxides interaction. This work was supported by RFBR under grant 09-03-00795-a.

140

PHOTOINDUCED OXYGEN ISOTOPE EQUILIBRATION ON TiO2-X SURFACE UNDER VISIBLE LIGHT IRRADIATION

A.A. Lisachenko, R.V. Mikhaylov, V.V. Titov

St.Petersburg State University, Russia

lisachen@photonics.phys.spbu.ru

Earlier we have shown that the photocatalytical reaction CO + NO + hν → N2 + CO2 on TiO2-x under irradiation in visible range takes place [1] due to the light absorption by oxygen vacancies and Ti3+ ions absorbing at 2.8, 2.5 and 2.0 eV [2]. The mechanism of reaction was suggested. In order to test the stability of surface defects in the reduced sample under irradiation in oxygen atmosphere and to test the photocatalytical activity in the absence of the reducing agent CO, the photoinduced oxygen isotope equilibration (POIE) 16O2 + 18O2 → 216O18O on TiO2-x was investigated. Experimental. The Degussa P-25 TiO2 powder (S =50 m2/g) was preliminarily purified by heating in oxygen flow at the pressure of 0.5 Torr for 10 hours at 870 K and then reduced by heating in vacuum at 870 K for 10 min. The experimental procedures of mass-spectrometric measurements in static and dynamic conditions were described earlier [2]. POIE measurements were performed in flow-through regime under oxygen pressures 10-5 – 10-3 Torr. High purity 18O2 and 16O2 were used to prepare nonequilibrium oxygen mixture. The samples were exposed to visible radiation (λ=436 nm) of a high-pressure mercury lamp (DRT-120) supplied with a water filter and a set of standard glass color filters SS-15 and JS-11 (LOMO). Photon fluxes were measured with a calibrated photocell F-17. Processing. In case of flow-through regime the equation describing the OIE reads:

dY/dt = - KY+(Y0-Y)/τ, where Y – is a parameter describing the non-equilibrium of output mixture (Y = 2α(1-α)-[C34], where α = [C34]+2[C36]), Y0 – is a parameter Y of input mixture, K – OIE rate constant, τ – is the characteristic pump time (τ = 5 s). The key parameter of OIE is the absolute rate of reaction:

R = KN = KLτ, where N – is the current number of oxygen molecules in the reactor volume, and L – is the oxygen input flow. Results and discussions. It was found that after switching-on irradiation on the POIE rate R increases monotonously up to its stationary value R0. After switching off the light the reaction continues ("memory" effect), and R slowly drops down to zero. The increasing and dropping branches could be approximated with exponential functions: Rincr = R0(1-exp(-t/τincr)) and Rdecr = R1-0exp(-t/τ1decr)+ R2-0exp(-t/τ2decr), respectively. No changes of total pressure occurred during POIE indicating the invariability of the adsorption-desorption equilibrium. The values of R0 and τ1decr depend on oxygen pressure P whereas τ2decr and increase time τincr do not change significantly with pressure. The stationary exchange rate R0 and both decrease times τ1decr and τ2decr diminish with temperature in range 290 – 470 K at a constant pressure. However, τincr is not affected by temperature in the range 290 – 370 K. The value of turnover number (TON) exceeds 50, i.e. the reaction is really the photocatalytical one. Both the model of the dissociative-associative reaction route via mobile ionic species 16O- and 18O- and the alternative associative-dissociative model assuming the formation of four-atomic oxygen complex O4

- are acceptable.

This work was supported by RFBR under grant 09-03-00795-a.

1. A.A. Lisachenko, R.V. Mikhailov, L.L. Basov, B.N. Shelimov, M. Che, J. Phys. Chem. C, 2007, v. 111. p. 14440.

2. Lisachenko, A.A.; Kuznetsov, V.N.; Zakharov, M.N.; Mikhailov, R.V., Kinet. Catal. 2004, 45, 189.

141

EFFECTS OF DONOR STRUCTURE ON TRIPLET ENERGY-TRANSFER FROM AMINES TO ALKENE IN SOLUTION

G.V. Loukova, A.V. Lukov, V.A. Smirnov

Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia

gloukova@mail.ru

Effects of the energy-donor and acceptor structure and their intermolecular interactions on effectiveness of resonant energy transfer account almost silent observations. Notably, unsaturated hydrocarbons are the substrates for catalytic systems of many organic syntheses, therefore, study of intermolecular interaction/ electronic communication in multi-component highly-organized systems in liquid and solid phase are of special interest. Olefins possess high-lying singlet states and energy of S1–T1 gap and therefore are useful as triplet energy acceptors. However, having unsaturated C=C bond, olefins can form complexes with metal complexes, as well as organic compounds. Respectively, it is of importance to study energy transfer at different conditions (varying solvents, electronic and structural features of the energy donor, etc.) Phosphorescence quenching of structurally-related aromatic amines with hexane-1 was studied in glassy solutions (largely, in ethanol) at 77 K. Such experiments in glassy/ solid media rule out dynamic component of ET that is characteristic for liquid phase. Effectiveness of energy transfer from emissive Т1-states of the aromatic amine series to Т1-state of olefin in solution at 77 K is well described by the Perrin equation viz. Φo/Φ = exp(N·V·[A]) for electron-exchange mechanism of interaction. Characteristic quantity for electron-exchange resonant energy-transfer effectiveness in this case is the critical radius Ro. For small concentrations of amines (С ≤ 10–4 моль/л), values of Ro were estimated from the Perrin equation, including 10.8 Å (donor aniline), 7.6 Å (diphenylamine), 7.2 Å (3-methyldiphenylamine), 6.9 Å (carbazole), 6.1 Å (N-ethylcarbazole), 6.4 Å (4,4'-dimethyldiphenylamine) and so on. Our data agree with assumption that Rо depends on structural features of the energy donor and reflects degree of orbital and quasi-chemical interactions in solution. We suppose that the critical radius of sphere for electron-exchange energy-transfer to olefin decreases with enhance in steric hindrance of phosphorescing donor molecules upon other close conditions (closeness of Т1-states of amines in energy and spectral features, and, therefore, integrals of absorption and emission spectra overlap, etc.) It should be noted that earlier, in the study of emission quenching of rare-earth metal salts with organic compounds in acetone solutions, it was suggested that steric hindrance from amines are responsible for the reduction in energy-transfer rate constants in the case of triplet energy acceptor triphenylamine and N-methyldiphenylamine. Acknowledgement. The authors gratefully acknowledge Professor A.E. Shilov for stimulating discussion and Russian Foundation for Basic Research (grant N 09-03-00379) and Russian Academy of Sciences for financial support.

142

ENERGY TRANSFER IN MOLECULES AND MOLECULAR SYSTEMS

G.V. Mayer, V.Ya. Artyukhov

Tomsk State University, Russia artvic@phys.tsu.ru

Influence of intermolecular interaction on spectral-luminescent characteristics of molecules and molecular systems always was an actual problem of molecular photophysics. One of the most interesting displays of this interaction is connected to nonradiative photoprocesses – energy transfer of electronic excitation between two chromophores. For interpretation of experimental results of research on energy transfer the phenomenological model and quantum-mechanical theory Ferster-Dexter is used. This theory allows to establish dependence efficiency of energy transfer from spectral -luminescent properties of molecules of a donor and an acceptor. In spite of the fact that this theory is not created for the description of energy transfer of electronic excitation between chemically connected molecules of the donor and an acceptor in bichromophore, it is widely applied to such systems. Typical bichromophoric molecules consist from donor and acceptor fragments which are connected in a uniform molecule by the bridge which is not transmitting electronic conjugation. In any polyatomic molecule after absorption of light quantum there are certain photophysical processes of transformation of excitation energy. Also it was quite natural to assume, that process of energy transfer of electronic excitation in bichromophoric molecules is realized by means of one of them. The main idea of our approach to an investigated problem consists in performance of quantum-chemical calculations of bichromophores as uniform molecular system without division into molecules of the donor and an acceptor (model of "supermolecule") with the subsequent estimation and the analysis of the photophysical processes occuring in such molecules. Starting the end of 80th years we carried out theoretical researches of the phenomenon of electronic excitation energy transfer in bichromophoric organic compounds and molecular systems. During researches it has been developed quantum-chemical model of studying of the orbital nature and spatial localization of electronic states and features of course of photoprocesses in such systems. In the present research bichromophores made on a basis of anthracene and naphthalene have been chosen. These molecules are well investigated experimentally and theoretically, that provides an opportunity of comparison of results with experimental data, and, hence, correct reproduction in quantum-chemical calculations the properties, both molecules, and compounds on their basis. The bichromophoric compounds with bridges of various length, a spatial structure and rigidity were investigated. For each molecule are calculated a little various conformations. Also bomolecular systems with the same spatial arrangement of molecules, as in bichromophores, are calculated. For all molecules and systems the rate constants of photophysical processes have been estimated. The results of calculations show, that in the investigated cases energy transfer of electronic excitation is carried out on the mechanism of internal conversion. The value of a rate constant of energy transfer depends on mutual orientation of a donor and an acceptor, distance between them. Influence of relative orientation of chromophores cannot be expressed simple analytical expression, as in the Ferster theory. On small distance between chromophores mutual orientation influences insignificantly on efficiency of energy transfer. Besides, influence of relative orientation of chromophores can mask presence of several channels of energy transfer. As a whole, results of the quantum-chemical approach to research of process of energy transfer are more productive and allow to explain features of this process more in details.

143

PROBE PHOSPHORESCENCE AND TRIPLET-TRIPLET ENERGY TRANSFER IN THE STUDY

OF CONFORMATIONAL CHANGES IN THE PROTEINS

A.G. Melnikov1, V.I. Kochubey1, A.B. Pravdin1, E.V. Naumova2, O.A. Dyachuk2, G.V. Melnikov2

1 - Saratov State University, Russia

2 - Saratov State Technical University, Russia melnikov_gv@sstu.ru

In this work we investigate processes of radiation and radiationless deactivation of electronic excitation energy of the polar and nonpolar luminescent probes bound to immunoglobulin, human serum albumin (HSA) and human blood plasma albumin. We chose xanthene dyes such as eosin, erythrosine and others as polar luminescent probes and polycyclic aromatic hydrocarbons (PAH) such as anthracene, pyrene and others as nonpolar luminescent probes. Investigation of the interaction of chosen reagents with proteins is urgent by several reasons. Firstly, most PAHs are cancerogen, and processes of their interactions with proteins are interesting for medicine. Secondly, this is known that xanthene dyes are used in photodynamical therapy. Thirdly, investigation of the mono- and bimolecular deactivation processes of electronic excitation energy are of scientific interest for development of the photonics methods in native systems research. Obtained absorption and fluorescence spectra of the probes made it possible to establish that polar dyes molecules and nonpolar PAHs get bound to the proteins. Absorption coefficients of several xanthene dyes and PAHs bound to proteins were determined. Delayed fluorescence (DF) and room temperature phosphorescence (RTP) of the probes bound to immunoglobulin, human serum albumin and blood plasma albumin were observed in oxygenless solutions. Significant increase of the intensity DF and RTP of the dyes and their lifetime on going from aqueous solutions to proteins indicates that probes bound to proteins are immobilized. We suggest the method for determination of the constants of probes binding to HSA globules, based on probes phosphorescence quenching by iodine ions in aqueous HSA solutions. The use of low concentrations of quencher (sodium idodide) for observing of the phosphorescence of the xanthene dyes is the advantage of method, because at these concentrations properties of the HSA globules do not change. On the base of obtained results we concluded that efficiency of quenching of the xanthene dyes molecules bound to HSA globules by water-soluble compounds, containing heavy atoms, are determined by interactions of the dyes molecules with proteins. Triplet-triplet energy transfer (TET) of electronic excitation energy between xanthene dyes and anthracene both bound to immunoglobulin, human serum albumin and blood plasma albumin was observed. So far as anthracenу are insoluble in water, TET is possible only in the protein globule. Rate constants of the TET energy transfer were determined subject to localization of donor and acceptor molecules in the protein globules. We found out that the rate constant of the energy transfer is sensitive to conformational changes of the protein globule under the action of surfactants. It is shown that triplet-triplet energy transfer method is applicable for registration of the intramolecular structural changes in protein globule.

144

COMBINED KINETIC, UV-VIS, FTIR AND TPD STUDY OF THE PHOTOCATALYTIC NO REDUCTION BY CO ON TiO 2

R.V. Mikhaylov1, A.A. Lisachenko1, B.N. Shelimov2,

G. Martra3, S. Coluccia3, M. Che4

1 - St.Petersburg State University, Russia 2 - N.D. Zelinsky Institute of Organic Chemistry RAS, Moscow, Russia

3 - Turin University, Turin, Italy 4 - Université P. et M. Curie, Paris, France

lisachen@photonics.phys.spbu.ru

Photocatalytic removal of organic and inorganic pollutants from indoor air is being intensively investigated. In most cases, titanium dioxide is used as a photocatalyst owing to its high activity, versatility, non-toxicity and low cost. Here we report on environmentally important photoassisted selective reduction of NO by CO on self-sensitized Degussa P-25 TiO2 at room temperature: NO + CO hν ½ N2 + CO2 [1]. It is found that the photocatalytic reduction of NO can occur on TiO2 catalysts both upon UV (λ< 380 nm) and visible light (λ > 380 nm) irradiation, in the latter case owing to the presence of electron-donor centers (Ti3+, F and F+ centers) in nonstoichiometric TiO2-x capable of absorbing visible light [2].The selectivity of the photoreaction to N2 production attains 90-95%, N2O is being a minor product. Mass-spectrometric analysis of the gas phase shows that the CO2 formed by the reaction does not desorb at 300 K suggesting formation of some carbonate or carboxylate stable surface structures which could potentially be detected by IR spectroscopy. However, the CO2 produced could be quantitatively desorbed after completion of the photoreaction by heating TiO2 to ~500 K. A multistage reaction mechanism is proposed based on combination of mass-spectroscopic kinetic analysis of gaseous reaction products with the studies of active centers in TiO2 by UV photoelectron and UV-Vis diffuse reflectance spectroscopy. The reaction scheme involves some N-containing surface intermediates (e.g., NO–, NO2

– and N2O) which could be the objects of an IR examination along with the above-mentioned C-containing species. A deeper insight into the mechanism of NO photoreduction with CO has been gained by studying successive reaction stages occurring in the adsorbed phase upon exposure of Degussa P-25 TiO2 photocatalyst to NO, CO and NO–CO mixtures in the dark and under subsequent light irradiation by means of FTIR and TPD spectroscopy. Only reversible weak adsorption of NO on surface Ti4+ ions is found to occur in the dark. UV-Vis irradiation greatly enhances the NO adsorption on Ti4+ and yields N2O, NO–, NO2

– and NO3– surface species. After irradiation of

TiO2 in a CO atmosphere, IR bands of surface CO2– and CO3

– species appear in addition to a continuous IR absorption tail towards lower wavenumbers due to free carries in the reduced semiconductor. When TiO2 is exposed to a equimolar NO–CO mixture, N2O and CO2

– are formed without irradiation supposedly by reaction 2 NO + 2 CO + O2– → 2 CO2

– + N2O. Subsequent light irradiation is accompanied by the accumulation of NO– and Ti4+…NO complexes. No TiO2 reduction occurs in this case. FTIR spectra show that NO– produced by the photo-induced adsorption of NO can be eliminated by reaction: NO– + CO hν CO2

– + ½ N2. It is believed this reaction is a key step in the nitrogen production by the photocatalytic process. The data obtained enable us to refine the earlier proposed reaction mechanism and to directly prove some of its key steps.

1. A.A. Lisachenko, R.V. Mikhailov, L.L. Basov, B.N. Shelimov, M. Che, J. Phys. Chem. C, 2007, v. 111. p. 14440.

2. A.A. Lisachenko, R.V. Mikhaylov, L.L. Basov, B.N. Shelimov, M. Che, High Energy Chemistry, 2008, v. 42, p. 80.

This work was supported by RFBR under grant 09-03-00795-a

145

MATHEMATICAL SIMULATION OF STRATEGY FOR THE CONTROL OF EXCITED- STATE INTRAMOLECULAR REVERSIBLE PROTON

TRANSFER IN THE MULTIPARAMETRIC FLUORESCENCE PROBES

V.A. Morozov

N.D. Zelinsky Institute of Organic Chemistry RAS, Moscow, Russia morozov@mail.ioc.ac.ru

Mathematical simulation, reversible proton transfer, multiparametric fluorescence probes. The study of the fluorescence molecular probes to definite the different types of intermolecular interaction simultaneously has been a large interest in the last year. For example, 3-hydroxyflavone and 3-hydroxychromone molecules were founded to fulfill the criteria of such multiparametric fluorescence probes [1]. A detailed knowledge of intramolecular dynamics of such molecules at transformation of light with two bands in fluorescence emission is necessary to successfully use these molecules as sensors. The knowledge may be obtained as a result of a comparison between the mathematical simulation of intramolecular dynamics at such fluorescence and corresponding experimental data. Dual fluorescence is connected with four-level molecular electronic systems which may be (following through [2]) as a result of the excited-state intramolecular proton irreversible or reversible (“coherent tunneling”) transfer at the enol-keto-photoisomerization. Mathematical simulation of the irreversible intramolecular proton transfer at the enol-keto-photoisomerization was carried in [3]. In the present report, the results of the similar modeling the excited-state intramolecular proton reversible transfer at photoisomerization of four-level molecule with exposed two light pulses (“pumping” pulse and the “probe” or “dump” pulse) are given. Simulation was conducted basing a numerical solution of a system of equations for the density matrix of model molecule at the different values of two classical described irradiation pulses. A set of values of parameters of light pulses were determined at which after the enol-keto-photoisomerization of model molecule induced by pumping pulse, the probe pulse lead to forced transition of the molecule from the tautomer excited electronic state to the ground electronic state of this form with the increment of photoisomerization effectiveness. Corresponding temporal changes of the molecular states population is obtained and shown on the pictures. The obtained results can serve as reference points at interpretation of the spectral-temporal experimental photoisomerization data for the molecules with a proton bond under irradiation of the molecule by two light pulses, to establish the mechanism of the excited-state proton phototransfer and to control the process by second light pulse. The work was partly supported by Program 1 of the Department of Chemistry and Materials Science, Russian Academy of Sciences. 1. A.P. Demchenko, A.S. Klymchenko, V.G. Pivovarenko et al. “ Multiparametric Color-

Changing Fluorescence Probes”. Journal of Fluorescence. Vol. 13. No. 4. 2003. 2. M. Kasha. “Proton-transfer Spectroscopy”. J. Chem. Soc. Faraday Trans. Vol. 282. P. 2379.

1986. 3. V.A. Morozov. “Numerical Simulation of Intramolecular Dynamics during Dual Fluores-

cence”. Optics and Spectroscopy. Vol. 105. No. 2. P. 176.

146

PREPARATION OF MAGNESIUM PHTHALOCYANINE NANOCRYSTALS

S.S. Nadolinskaya1, A.M. Meshkov2, V.G. Maslov2, V.I. Korotkov1

1 - St.Petersburg State University, Russia

2 - St.Petersburg State University of Information Technologies, Mechanics and Optics, Russia korotkov@paloma.spbu.ru

Phthalocyanines characterize very high thermal, photo, chemical stability and photoelectrical sensitivity. Due to this their properties they are used as photosensitive devices in modern laser printers, optical disks and as photochemical redox agents in solar conversion. Special interest arises for preparation and investigation phthalocyanine nanocrystals because their spectral, luminescence and photophysics properties change very significantly comparison with molecular properties. Conversion of some phthalocyanines from molecular to a crystalline state drastically changes the photophysical and photochemical properties. Therefore nanocrystals provided to be quite perspective objects for investigation. We choose Mg phthalocyanine as object for investigation on the basis of its similarity and relationship to chlorophyll. Now there are some articles describe method of preparation micro- and nanosized crystals of magnesium phthalocyanine. Phthalocyanine crystals have been preparated by addition water into solution of Mg phthalocyanine in acetone. Water acts as “salting out” solvent. Size of crystal limits by volume of adding water, temperature and time of crystallization. Final fixing of crystal dimension acts by introduction binding polymer into colloidal solution. Some times magnesium phthalocyanine did not dissolved in acetone — during long storage crystals come to stable crystal modification due to polymorphic conversion. Acetone does not dissolve these crystals. Herein we developed new method for fabrication nanocrystals of magnesium phthalocyanine: as solvent we used sulfuric acid. This acid very effective dissolves all crystal modification of magnesium phthalocyanine. Water was also “salting out” solvent. To avoid presence of acid and dissolving increased crystals acid has been “washout” from solution. Also this procedure was used for fixation size of crystal. Process of pigment crystallization was controlled by arising new bands of electronic absorption intrinsic Mg phthalocyanine. Absorption spectra of crystals, grown by our method, vary from spectra known individual crystal forms. The complex structure of the spectra of our samples is attributed to the simultaneous presence of some crystal phases and the molecular phase of Mg phthalocyanine in the samples. According to the literature data absorption band near 675 nm belongs a-form of nanocrystal of pigment, broad spectrum in region 550–850 nm with the main maximum at 700 nm is characteristic forb-form, intensive absorption band at 825 nm corresponds to x-phase. Registered spectra clearly demonstrated appearance of broad intensive band in zone 500–850 nm with clearly distinguished maxima at 630 and 700 nm. Maximum at 630 nm apparently correspond absorption band of the molecular phase of Mg phthalocyanine. Maximum at 700 nm – absorption band of the b-form. Also probably there is presence of a-phase. Absence of absorption band at 825 nm implies that x-phase of Mg phthalocyanine in such conditions does not generates. Therefore one can conclude that proposed method of preparing of Mg phthalocyanine nanocrystals produces mainly b-form nanocrystals.

147

PHOTOCHEMICAL TRANSFORMATIONS OF CHALCONE PODANDS IN THE CRYSTALS AND SOLUTIONS

I.G. Ovchinnikova1, O.V. Fedorova1, A.V. Druzhinin2,

G.L. Rusinov1, V.N. Charushin1

1 - I.Ya. Postovsky Institute of Organic Synthesis RAS, Ekaterinburg, Russia 2 - Institute of Metal Physics RAS, Ekaterinburg, Russia

iov@ios.uran.ru

In connection with search of new principles of information recording and working out of its carriers turn to the technologies related to engineering of high-organized controlled molecular structures, being an object of research of supramolecular chemistry, is obvious. One of the most promising macromolecular compounds containing photo-operated groups and, hence, capable to transform light energy into chemical bond energy can be chalcone podands. In this regard the synthesis of podands with 2-oxybenzylideneacetophenone fragment 1a-c is carried out and their photochemical transformations into a solid-state and solutions are investigated.

OO

On

O

Ph

O

Ph

OO

On

O

Ph

O

Ph

O

Ph

OO

On

O

Ph

O

Ph

OO

On

O

Ph

OO

On

OO PhPh

OO

On

OO Ph

Ph

OO

On

OO PhPh

OPh

O

O

O

n

OPh

O

OC(O)Ph

n

m

O

C(O)Ph

On

C(O)PhPh(O)C

. .

+*

hν

*

KSCNCH3CN (DMF)

∆λ∆λ∆λ∆λ 328 - 496 nm

∆λ∆λ∆λ∆λ 258 - 400 nm

2a,b

r

c

t

r

r r

cc

c

c

t t

t

t

t t

3a,b 5a-c

4a-c 6b,c

αβ

n = 0 (a), 1 (b), 2 (c)

hν

1a-c

solid

n = 1, m = 1 (a);n = 2, m ~ 100 (b)

Distinctions in the parameters of chalcone podand preorganization to intermolecular photoinduced [2+2]-cycloaddition in crystals are revealed. It was found that the chalcone-podand 1b (n=1) forms stereoregular cyclobutane containing polymer chains 2b throughout a single crystal. In a case of chalcone podand 1a (n=0) photocycloaddition becomes impossible in the single crystals, however mechanical destruction of crystals leads to the formation of superficial with π-stacking dimers layers in which photodimerization proceeds by reducing topotactic control from a molecular lattice with formation of dipodand 2a. On the contrary, in solutions chalcone podands in the presence of templates (alkali metal ions) enter into intramolecular reaction of photocycloaddition with formation of corresponding cyclobutane containing dibenzo-crown-ethers 3-6. With application of such methods as X-ray, UV, 1H and 13C NMR spectroscopy it has been shown that the reaction of intramolecular stereoselective dimerization takes place (with the formation mainly of structures β- and γ-truxinic type), the speed of photoinduced [2+2]-cycloaddition depends on the size of oxyethylene spacer and stereoorientation of chalcone fragments in the podands. Also, it has been found that the selectivity of photocycloaddition can be regulated by change of template concentration and variation of the range of light irradiation. Work is executed with financial support of the Russian Foundation for Basic Research (grants 07-03-96111, 07-03-96113); the Presidium of the Russian Academy of Science (the project «Design of new supramolecular structures containing heterocyclic fragments»).

148

TWO-PHOTON PHOTOPROCESSES IN MOLECULAR SYSTEMS

V.G. Plotnikov1, V.A. Smirnov2, M.V. Alfimov1

1 - Photochemistry Center RAS, Moscow, Russia 2 - Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia

vas@icp.ac.ru

Two-photon processes occurring in polyatomic molecules in condensed phase are reviewed. Mechanism and kinetics of the light second photon consumption and regularities of fundamental two-photon processes: ionization, electronic excitation energy transfer, dissociation with hydrogen atom and molecular products elimination are discussed. Experimental state of art of the method is demonstrated. One of the main requirements to the molecules of effective polymer photostabilizers is highlighted to be the absence of two-photon processes which is possible at effective radiationless conversion, initiated by reversible adiabatic chemical reactions. Based oh this idea, properties of main types of polymer stabilizers is interpreted.

149

FTIR STUDY OF METHANE INTERACTION WITH OXIDE ADSORBENTS

M.S. Poretskiy, A.A. Tsyganenko

V.A.Fock Institute of Physics, St.Petersburg State University, Russia

tsyg@photonics.phys.spbu.ru

Low temperature adsorption of methane and deuterated methane (CHD3) has been studied by IR spectroscopy on zeolites: CaY, SrY, ZnY, NaY, RbY, KY, CsX, RbX, NaX, mesoporous MCM-41 silica, and oxides CaO, ZnO, ZrO2, TiO2 in order to find out spectral manifestations of adsorption, nature of surface sites and the structure of adsorbed complexes. Spectra were compared with those of CO adsorbed on the same adsorbents, and besides the shifts of the absorption bands, extinction coefficients ε were measured, in particular, for ∆ν1 vibration. The frequency shifts of methane ν1 band increase regularly with the electron accepting ability of cationic sites characterized by the value of blue frequency shift of adsorbed CO, which increases in the sequence: MCM-41>RbY>HY>NaY>SrY>CaY>ZnY. Comparison of these data shows that the bands below 2900 cm-1 cannot be attributed to ν3 vibration, as proposed earlier [2] for the most intense bands at 2850-2895 cm-1 in the spectra of CH4 on mordenites, but is rather due to the ν1 mode of methane adsorbed on cationic sites. This is in accordance with our spectra of adsorbed CHD3, which reveal no bands seriously shifted downwards. The strongest sites of CO adsorption on X-zeolites or CaO are basic oxygen ions. One could, thus, anticipate that methane adsorbed on CsX should also interact with electron donor oxygen sites. The spectra of CH4 adsorbed on CsX, besides the band near 2900 cm-1, assignable to interaction with residual Na+ cations, contain a band at 2876 cm-1, which can be attributed neither to complexes with Na+, nor with Cs+ cations, and belong, apparently to methane molecule bound by the H-bond-like interaction in CH4…O complexes with oxygen atoms. CO adsorption on CaO, besides the comparatively weak interaction with the cations, leads to the formation of carbonite CO2

2- species as a result of adsorption on electron donor surface oxygen ions [1]. The band of ν1 mode of CH4 on CaO at 2885 cm-1 does not fit the above correlation for the cationic sites, and should also be assigned to methane adsorbed on surface oxygen ions. This conclusion is supported by the results of experiments with CO addition to CaO with preadsorbed methane, which demonstrate a competitive adsorption of both the molecules on the same anionic sites. According to quantum-mechanical calculations, with cationic sites methane should form complexes, where three CH bonds are directed towards the cation, and the fourth oriented outwards [3]. For the complexes with anions one could expect, on the contrary, one CH bond directed towards the anion, as in the case of fluoroform, which forms weak H-bonds with proton-accepting oxygen centers. However, in such a case methane should reveal a blue shift of CH vibration [4], but neither CH4 nor CHD3 adsorbed on basic adsorbents, such as CaO manifest any CH stretching frequency increase. To explain this contradiction, we can even adopt for the C-H bond in methane very weak, but opposite polarity, like in the case of hydride-like B-H bond. Then the geometry of complexes should be different, but the observed red frequency shifts would be consistent with the data of calculations. The question of the geometry of surface methane complexes still needs new experimental data.

The work was supported by RFBR, grants 06-03-32836a and 06-05-64646a.

References: [1] Babaeva M.A., Bystrov D.S., Kovalgin A.Yu., Tsyganenko A.A. J. Catal., 123 (1990), 396. [2] Khodakov A.Y., et al. J. Chem. Soc. Faraday Trans., 89 (1993) 1393. [3] Knozinger H., Huber S., J. Chem. Soc. Faraday Trans., 94 (1998), No 15, 2047. [4] K. Hermansson, J. Phys. Chem. A, 106 (2002) 4695.

150

LUMINESCENT INVESTIGATION OF ACRIDINE HOMO-CONJUGATED COMPLEX

J.A. Rozhkova1, A.A. Gurinov2, S.B. Lesnichin1, I.G. Shenderovich1, V.G. Maslov3, V.I. Korotkov1

1 - Physics Department, St.Petersburg State University, Russia

2 - Chemistry Department, St.Petersburg State University, Russia 3 - St.Petersburg State University of Information Technologies, Mechanics and Optics, Russia

korotkov@paloma.spbu.ru

Essential methods to studying of hydrogen bond are NMR and IR-spectroscopy. At last time one begins to use optical UV-Vis spectroscopy. It is worth seeing luminescence to examine hydrogen bond. This method characterizes considerable sensitivity in comparison with UV-Vis spectroscopy, NMR and IR-spectroscopy. Therefore it has been investigated luminescence spectra of acridine and protonated form of acridine – acridinium with counter-ion BARF. Also we took attempt to detect luminescence spectrum of homo-conjugated complex acridine + acridinium. Acridine was selected for studying because of its absorption spectrum exposed the greater changes under protonation in comparison of other nitrogen-containing aromatic compounds - pyridine, collidine, quinoline, quinaldine - which we optically studied previously. Dichloromethane was used as aprotonic solvents. Luminescence spectra and excitation luminescence spectra of solutions of acridine, its protonated form – acridinium and mixture of acridine and acridinium at room temperature has been studied. There are intensive maximums at 290 nm, 320 nm, 400 nm, 418 nm and 440 nm in luminescence spectra of acridine under different wavelengths of excitation. Excitation luminescence spectra were detected for all these maximums. Luminescence spectra of acridinium solution exposed considerable rising of intensity and significant long wave displacement in comparison of spectra of acridine – maximums locate at 460 nm, 480 nm and 525 nm. This effect can be explained by the change in the most important fluorescence parameters. Introduction onto molecule of a strong electron-donor group usually causes dramatic changes in all spectral-luminescent parameters. The oscillator strength of the S0→S1 electronic transition usually increases and, as a rule, the fluorescence quantum yield also increases. Probably protonation results in analogous effect. Luminescence spectrum of mixture of acridine and acridinium consists of all above enumerate maximums. Mathematical treatment of these spectra shows difference between luminescence spectrum of mixture and superposition of acridine spectrum and acridinium spectrum. Addition of acridine and acridinium spectra with different coefficients does not give spectrum of mixture. We calculated remainder between spectrum of mixture and sum of acridine and acridinium spectra. This difference spectrum, with two maximums at 440 nm and 470 nm, hypothetically attributed to homo-conjugated complex acridine + acridinium.

151

PROTONATED NITROGEN-CONTAINING AROMATIC MOLECULES. SPECTROSCOPIC INVESTIGATION

J.A. Rozhkova1, A.A. Gurinov2, S.B. Lesnichin1, I.G. Shenderovich1, V.G. Maslov3, V.I. Korotkov1

1 - Physics Department, St.Petersburg State University, Russia

2 - Chemistry Department, St.Petersburg State University, Russia 3 - St.Petersburg State University of Information Technologies, Mechanics and Optics, Russia

korotkov@paloma.spbu.ru

Many works devoted to study of hydrogen bond by NMR and IR-spectroscopy. Optical UV-Vis spectroscopy provides a supplementary interpretation of experimental data on hydrogen bond and proton transfer phenomena, obtained using different methods. But in many cases the limitation of UV-Vis is the absence of measurable differences between spectra of free and protonated species. Nitrogen-containing aromatic compounds: pyridine, collidine, quinoline, quinaldine. acridine were experimentally studied by UV-Vis spectroscopy. Heterocyclic bases are convenient objects for investigation because their proton-accepting abilities can be selectively varied by introducing substitutes in meta- and para-positions. Besides that steric effects can be controlled using ortho-substitutions. The higher is the proton-accepting ability of a molecule the stronger a competition of two equivalent molecules for the proton in their homo-conjugated complex is. Dichloromethane and chloroform were used as solvents. To investigate the dependence of counter-ion size on spectra of protonated species we used BrF4 and BARF. Optical spectra of protonated species for both “small” BrF 4 and “large” BARF ions demonstrated appearance of absorption bands in the long-wave region of spectra and decrease of the intensity of absorption band in the short-wave part. The long-wave border of the spectra moves to 290 nm in the case of the pyridinium, to 292 nm in the case of the collidinium, and to 345 nm for quinaldinium. The largest shift of the long-wave limit has been revealed in the acridinium absorption spectrum. The spectrum of acridinium differs from the acridine spectrum by disappearance of a maximum at 380 nm and by appearance of new absorption bands in the region 400 – 460 nm and in the short-wave region 270-290 nm. Also after protonation of the acridine molecule one can see in the absorption spectrum a shift of a maximum at 357 nm towards the short-wave part to 1nm. It was shown by NMR that investigated molecules and its protonated species form in solutions homo-conjugated complexes. These complexes are forming due to hydrogen bonding between N atom of heterocyclic base and proton of its protonated species. To reveal such complexes in UV-Vis spectra we used titration method: solutions of a heterocyclic bases were added by small parts to solutions of protonated species. The absorption spectra of homo-conjugated complexes were calculated from the absorption spectra of mixtures. Hydrogen bonds in such complexes are weak. Hence the dynamic equilibrium between isolated species and their hydrogen bonded complexes in solution is temperature dependent. The relative concentrations of homo-conjugated ions increase upon cooling. For example, for a mixture of quinoline and quinolinium in chloroform the absorption in the region 290 – 330 nm increases upon cooling from 200 to -650 C that indicate a disposition of homo-conjugated complex absorption spectrum in this spectral region.

152

ETHYLENE PHOTOPOLYMERIZATION ON ZEOLITE NA–ETS-10: IR SPECTROSCOPIC STUDY

A.V. Rudakova1, R.F. Lobo2, V.K. Ryabchuk1, K.M. Bulanin1

1 - V.A. Fock Institute of Physics, St.Petersburg State University, Russia

2 - Department of Chemical Engineering, University of Delaware, Newark, USA brigg7@yandex.ru

The photocatalytic activity of ETS-10 titanium silicalite has been known to significantly differ from the activity of a traditional Ti2O photocatalyst [1]. This material has attracted increased attention because of particular features of its structure, which contains a three-dimensional network of channels of large cross-section, formed by twelve-membered rings. Such a structure has significant advantages for catalysis and photocatalysis because of better condi-tions for diffusion of molecules in pores and because of the possibility for selecting molecules with the desired shape and size. In this work [2], we studied UV induced polymerization of ethylene on Na–ETS-10 titanium silicalite by IR spectroscopy. The local structure of the adsorbent was studied with the help of Raman spectroscopy. The data obtained from the IR spectra were analyzed using 2D correlation spectroscopy initially proposed first by Noda [3-4]. It was found that reaction being under study proceeds at room temperature yielding polyethylene. We suggest that holes O• generated by the UV radiation in –Ti–O–Ti– chains can initiate the reaction of polymerization of ethylene by the following mechanism: О–• +H2C = CH2 → О – СH2 – СH2 – CH2 – ... . 2D correlation spectra supported well conclusions obtained from the experimental data. References 1. Southon P.D., Howe R.F. // Chem. of Mater. 2002. V. 14. 10. P. 4209-4218. 2. Rudakova A.V., Lobo R.F., Bulanin K.M. // Optics and Spectroscopy. 2008. V. 105. 5. P.

739-744. 3. Noda I. // Bull. Am. Phys. Soc. 1986. V. 31. P. 520. 4. Noda I., Ozaki Y. Two–dimentional Correlation Spectroscopy - Applications in Vibrational

and Optical Spectroscopy. John Wiley&Sons Ltd, 2004.

153

PHOTO-OZONOLYSIS OF CHLORINATED ETHENES AND HYDROGEN CYANIDE ON WATER ICE FILMS

A.V. Rudakova, I.L. Marinov, A.A. Tsyganenko

V.A. Fock Institute of Physics, St.Petersburg State University, Russia

ilya.marinov@gmail.com

Photochemical transformations and photo-induced oxidizing processes on ice surfaces as well as in the bulk of ice particles are of a great importance for atmospheric science, ecology and astrophysics. In this work, photo-ozonolysis of chlorinated ethenes and hydrogen cyanide on/in icy films has been investigated by means of FTIR spectroscopy at 77 – 200 K. The cell for spectral studies of adsorbed molecules at variable temperatures (55-370 K), described elsewhere [1], was equipped with a device for vapour sputtering from the heated capillaries and deposition onto the inner BaF2 windows of the cell, cooled by liquid nitrogen. The systems under investigation were irradiated by a 120-W high-pressure mercury lamp DRK-120 (MELZ). Ozone was produced from O2 by electric discharge. Ozonolysis of C2H3Cl, gem-, cis- and trans- dichlorethenes and C2Cl4 adsorbed on D2O ice film has been studied. It was found that ozone co-adsorption with C2H3Cl at 77 K readily leads to ozonolysis reaction, while for the three isomers of C2Cl2H2 it starts only at 120 – 150 K. For C2Cl4 co-adsorbed with O3, ozonolysis reaction doesn’t occur even at 200 K, however, UV-irradiation of this system leads to appearance of new bands already at 77 K. For the same compound, such as gem- C2Cl2H2, the poducts of photo-ozonolysis and ozonolysis at higher temperatures are not the same, testifying for different mechanisms of these reactions. Analysis of these data infers that mechanism of ozonolysis can be described by Criegee scheme, and leads to formaldehyde, formyl chloride, phosgene and CO2 as ultimate products. The latter two were also found among the products of photo-ozonolysis. Ozone adsorption on solid HCN film at 77 K in the dark doesn’t manifest any changes in the spectra, while under UV irradiation new products appear. In order to identify the products isotopic experiments with DCN and 18O3 were carried out, as well as photolysis of pure NO adsorbed on water ice film and photo-ozonolysis of solid N2O film. Photolysis of HCN was not detected at the conditions of experiment. Studies of HCN photo-ozonolysis dependence on the wavelength of incident radiation has shown that the spectrum of acting light coinsides with the Hartley band at 200-300 nm. Apparently, this is photodissociation of ozone which accounts for photo-ozonolysis. According to the obtained spectral data, isocyanic acid (HNCO) is an intermediate product of this reaction, while CO2 and NxOy seem to be the ultimate products. Photo-ozonolysis of pure nitrous oxide film at 77 K results in formation of NO dimers. At the same time photolysis of solid NO leads to N2O formation. The two photo-chemical processes, thus, somehow counterbalance each other. To investigate the influence of water addition on the reaction mechanism, photo-ozonolysis of hydrogen cyanide in mixed HCN/H2O ices at 77 K has been studied. The surface properties of HCN/H2O ices with different component ratio have been tested by low-temperature CO adsorption [2]. It was found that water admixture promotes faster HNCO formation during the photo-ozonolysis process. Apparently, water also induces the dissociative ionization of HNCO and formation of the cyanate ion (OCN¯). Thus, increase in the reaction rate is due to photo-induced isocyanic /cyanic acid (HOCN) isomerization. Acknowledgments. The work was supported by INTAS (grant 03-51-5698) and RFBR (grants 06-03-32836 and 06-05-64646). 1. Otero Areán С. et al. Eur. J. Inorg. Chem., 2001, No 7, 1739. 2. Rudakova A.V. et al. Langmuir, 25 (2009), 1482.

154

THE EFFICIENCY OF UV STIMULATED FORMATION OF ACTIVE CENTERS AT THE SURFACE OF MICRO-

AND NANO-DISPERSED ZrO2 PHOTOCATALYSTS

V.K. Ryabchuk1, A.V. Emeline1, G.V. Kataeva2, G.N. Kuzmin1, N.V. Sheremetyeva1

1 – V.A. Fock Institute of Physics, St.Petersburg State University, Russia

2 – Faculty of Natural Sciences, Dimitrovgrad Subdivision of Ulianovsk State University, Russia ryabchuk@photonics.phys.spbu.ru

One of the major problems to design an efficient photocatalytic system for practical application is the development of highly active photocatalyst. The decreasing of the catalyst particle size seems to be a proper approach. It confirms by some simple models (see for example [1]). However as known for titania photocatalysts, the model expectations are not fulfilled quite often in practice. The efficiencies of UV induced surface active centers formation for micro- and nano dispersed zirconia photocatalysts have been compared in present studies. Zirconia powders with SBET = 7 m2/g and SBET = 71 m2/g (particle size d ∼ 100 and 15 nm respectively) have been studied. Here we present two sets of experimental results. The first one is the kinetics of active surface centers (color centers of V and F type) formation under UV illumination in micro dispersed zirconia powders in vacuo and in gases compared with corresponding kinetic data obtained for nano sized powders. In addition, the spectral dependencies of quantum yields of hydrogen and oxygen photoadsorption on zirconia samples are also confronted. The results can be summarized as following: 1) The photo catalytically active centers of the same type (so called color centers of F and V type) are induced by UV light at the surface and in near surface area of both micro and nano sized zirconia; 2) The total efficiency of such centers formation under illumination in vacuo is of 5-10 fold higher for micro sized powders comparing with the efficiency of photocoloration in nano sized zirconia; 3) the additional growth of surface V type centers due to photoadsorption of oxygen on surface F type centers and vice versa the increasing V centers under illumination in hydrogen compared with illumination in vacuo [2,3] are approximately ten fold higher for nano sized particles than for micro sized ones. The spectral dependencies and the values of the quantum yields of studied photoprocesses are similar for both types of zirconia samples. The obtained results are treated on the base of the model of photocatalyst particle [4] in which the efficiency of active centers formation is determined by the dimensionless rations of parameters such as the particle size d, the inverse absorption coefficient α-1 for particle substance, and diffusion length L for UV induced electrons and holes. References

1. Gerihcher H. // Electrochimica Acta. -1993.- Vol.38. - No. 1. - P. 3 - 9. 2. Emeline A.V., Kataeva G.V., Ryabchuk V.K., Serpone N. // J. Phys.Chem. B. - 1999. -

Vol.103. - No 43. - P. 9190 - 9199. 3. Emeline A.V., Sheremetyeva N.V., Khomchenko N.V., Kuzmin G.N., Ryabchuk V.K., Teoh

W.Y., Amal R.// J. Phys. Chem. C. - 2009. -Vol. 113. - No 11. - P. 4566 - 4583.

4. Emeline A.V., Ryabchuk V.K., Serpone N //J. Phys. Chem. B. - 1999. - Vol. 103. - No. 8. - P. 1316 - 1324.

155

DECAY TIME OF ACTIVE SURFACE CENTERS ON WIDE BAND GAP METAL OXIDES

V.K. Ryabchuk1, A.V. Emeline1, G.V. Kataeva2, N.V. Sheremetyeva1

1 – V.A. Fock Institute of Physics, St.Petersburg State University, Russia

2 – Faculty of Natural Sciences, Dimitrovgrad Subdivision of Ulianovsk State University, Russia ryabchuk@photonics.phys.spbu.ru

Two sorts of photo induced active surface centers for wide band gap (Eg ≥ 3 эВ) oxide photocatalysts distinguishing by decay time, had been considered early [1]. The first type of so called short live active centers referred to surface shallow traps for photo carriers with decay time within 0,1 – 0,001 s range. The second type of active centers (long-live centers of post-sorption) considered as color centers-like deep thermally stable traps with indefinitely long decay time at ambient conditions. The results of mechanistic studies of different physical pathways of deactivation for active states of centers on the surface of wide band gap oxides are presented here. It has been shown that the given color centers-like surface centers with trapped carriers decaying via recombination with photo carriers of opposite sign manifest themselves as short-live centers under illumination. At the same time, these centers behave as long live centers of post-sorption on pre-irradiated in vacuo wide bang gap oxides in the dark. The decay time of the centers under continued illumination depends on intensity of actinic light. Thus, the dependence of photoadsorption rate on gas pressure and on light intensity follows formally to Langmuir-Hnshelwood kinetics at constant light intensity only. Typically the so called Langmuir constant depends inversely on actinic light intensity in a case of linear photo carriers recombination for a given wide band gap photo catalyst. It has been demonstrated by means of recombination photodesorpton studies and by photoadsoption kinetics numerical simulations that recombination cross section of active surface centers drastically reduces when they transform into adsorption complexes (the center + photo adsorbed molecule + trapped carrier) at chemical stage of photoadsorption. The latter is the reason of reducing of so called “post-sorption coefficient” with increasing of irradiation time established for a series of wide band gap oxides [1]. In addition, the same above mentioned reduction of the recombination cross section leads to changing in a number of color centers of V and F type created by actinic light due to photoadsorption, compared with that created under illumination in vacuo at the surface and in near-surface area in micro- and nanoparticles of wide band gap oxides [2]. The similar manifestations of recombination decay of active centers and intermediates for a case of photo oxidation of phenols over titania photo catalyst in aqua are also discussed. References

1. Solonitzyn Yu.P., Prudnikov I.M., Yurkin V.M. // Russ. J. Phys. Chem. - 1982. -Vol.57. – No. 8. - P. 2028 - 2030.

2. Emeline A.V., Kataeva G.V., Ryabchuk V.K., Serpone N. // J. Phys.Chem. B. - 1999. - Vol.103. - No 43. - P.9190-9199.

156

STRUCTURE AND PHYSICO-CHEMICAL PROPERTIES OF PHOTOACTIVE SUPRAMOLECULAR SYSTEMS BASED

ON CROWN-CONTAINING OLIGOTHIOPHENE DERIVATIVES

S.L. Selector1, V.V. Arslanov1, O.A. Fedorova2, E.V. Lukovskaya2, A.V. Bobyleva2, N.A. Tarasova1, Y.V. Fedorov3, O.A. Raitman1, A.V. Anisimov2

1 - IPCE RAS

2 - Chemistry Department of MSU 3 - IOEC RAS

pcss_lab@mail.ru

Electronic and optical properties of oligothiophenes with various covalently attached functional groups facilitate their use in electroluminescent devices, sensors, solar cells, organic laser diodes and field effect transistors. This research is devoted to comparison of structure and properties of ultra thin films of two tristhiophene molecule geometric isomers bearing crown-styryl fragments (I , II ). Their supramolecular assemblies were obtained by two different ways: by complex formation with Ba(ClO4)2 salt in organic solution and by Langmuir-Blodgett (LB) film formation.

S

O

O

O

O

O

S

O

O

O

O

O

S

I

optical, electrochemical unit

binding center

O

OO

OOO

OO

OOS S

S

O

OO

OOS

SO

OO

OOS

stacking interactionunder complexing

stacking interactionin LB film

coordinationinteraction

S

O

OO

OO

OO

OOO

SS

Ba+2

OO

O

O

O

SS

S

O

O

I I intramolecularcomplexing

O

O

O

O

O

SS

S

O

O

O

O

O

OO

OO

O

OOO

OO

SS

S

isomerisation at air/water interface

J-aggregate staking in LB film

By means of quite a number of different physico-chemical methods it was established that the molecular structure influences substantially on the supramolecular organization (Scheme 1). As it was shown earlier in the presence of barium perchlorate in an organic solvent compound I forms the H-aggregate mode sandwich barium complexes. These supramolecular complexes are inflorescence and inactive in photoisomerization reaction. The electronic absorbance spectra of compound I LB films showed the significant blue shift of the main band, which indicates the intense H-aggregate formation. On the other hand compound II forms intramolecular sandwich complex in organic solutions of barium perchlorate (scheme). The addition of metal ions forces the styryl fragments to change their position from anti- in free ligand to syn- in sandwich complex. The red shift of both absorbance bands in compound II LB film spectra was recorded. The generation of J-aggregates composed of similar syn-conformers is mostly probable for compound II in LB films. Moreover by use of the in situ fiber-optic UV-spectroscopy measurements it was shown that aggregate formation in Langmuir films takes place directly during monolayers compression. The reversibility of such aggregation was established: the decompression (expansion) of the monolayer restores its monomer state. The substantial effect of the aggregate type on the electrochemical and optical behavior of two geometric isomer LB films was demonstrated and discussed.

Scheme 1

water air

157

DETERMINATION OF MAGNETIC-DIPOLE TRANSITION 5D0 – 7F1 PURITY IN EUROPIUM CHLORIDE LUMINESCENCE IN SOLUTIO N

BY ENERGY TRANSFER TO DYES

T.A. Shakhverdov

St.Petersburg State University of Information Technologies, Mechanics and Optics, Russia teimur@soi.spb.ru

Recently interest to so-called “photon metamaterials” [1] has increased. Meanwhile, their properties, in particular negative refraction, can be reproduced with use magnetic-dipole transitions (MDT) of lanthanide ions [2, 3]. However purity of such transitions remains practically not studied. We define an admixture electric dipole transition (EDT) in radiative 5D0 → 7F1 MDT of europium chloride in heavy water by energy transfer to dyes. The mechanism of such energy transfer has been studied for the first time by us in works [4–6]. Later these works have received the further advancement in connection with problems of biology [7–9] and nanophotonics [10]. For definition of contribution EDT in MDT it has been used more than 20 dyes of triphenylmetane, thiazine, оxazine and other classes with absorption spectra in various degree overlapped both with MDT, and with EDT of Eu(III) in radiation. Measurements are carried out by means of Eu(III) luminescence lifetime quenching. It was expected, that contribution 5D0 → 7F2 EDT in 5D0 → 7F1 MDT Eu(III) as a result of mixture of levels 7F1 and 7F2 will not exceed 10 %. However it may be as much as 20 ± 10 %. Influence of the size of dyes and their aggregation on the received results is discussed. References:

1. M.M. Litchiniter, V.M. Shalaev, Laser Phys. Lett. 5 (2008) 411. 2. Q. Thommen, P. Mandel, Opt. Lett. 31 (2006) 1803. 3. N. Noginova, G. Zhu, M. Mavy, M.A. Noginov, J. Appl. Phys.103 (2008) 07E901. 4. V.L. Ermolaev, T.A. Shakhverdov, Opt. Spectrosc. 30 (1971) 515. 5. T.A. Shakhverdov, V.L. Ermolaev, Оpt.i Spectrosk. 33 (1972) 941. 6. Т.A. Shakhverdov, E.N. Bodunov, Opt. Spectrosc. 34 (1973) 646. 7. C.F. Meares, L.S. Rice, Biochemistry. 20 (1981) 610. 8. T. Yamamoto, S. Nakayama, N. Kobayashi et al., J. Mol. Biol. 241 (1994) 714. 9. K. Blomberg, P. Hurskainen, I. Hemmila, Clin. Chem. 45 (1999) 855. 10. S.S. Dudar’, E.B. Sveshnikova, V.L. Ermolaev, Opt. Spectrosc.104 (2008) 724.

158

COMPARATIVE STUDY OF SPECTRAL PROPERTIES OF CROSS-CONJUGATED BISAMINOKETONES AND DINITRILES

L.A. Shvedova1, A.S. Tatikolov1, Zh.A. Krasnaya2

1 – N.M. Emanuel Institute of Biochemical Physics RAS, Moscow, Russia

2 - N.D. Zelinsky Institute of Organic Chemistry RAS, Moscow, Russia shvedova@sky.chph.ras.ru

The spectral-fluorescent properties of a set of dye molecules (ketocyanines – polyenic bis-ω,ω'-aminoketones, and their analogues – dinitriles containing a dicyanomethylene fragment instead of the carbonyl group) was investigated in solvents of different polarity and ability for specific and nonspecific solvation.

The absorption spectra of dinitriles are shifted bathochromically with respect to the spectra of corresponding ketocyanine dyes. This can be explained by elongation of the chromophore chain by one double bond in dinitrile molecules. Based on the solvatochromic shifts of the absorption and fluorescence spectra, the specific and nonspecific solvation of dinitriles and corresponding ketocyanies was studied. The photophysical data obtained for the examined molecular structures were correlated with different empirical parameters, which characterized solvation ability of a solvent: the Dimroth–Reichardt parameter ET(30), the acceptor number AN, the donor number DN, and the parameter π* for characterization of solvent polarity/polarizability. For ketocyanines under investigation a linear correlation is observed between the wavenumbers of the absorption maxima and the acceptor number AN characterizing the specific solvation. It is confirmed that in the ketocyanie solutions the electrophilic solvation plays a main role. For dinitriles a linear correlation for the wavenumbers of the absorption maxima was obtained as f(π*, AN, DN). In this case a significant contribution of nonspecific and nucleophilic solvation is observed in addition to electrophilic solvation.

NMe2Me2N

O

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β

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δ

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dinitriles ketocyanines

159

DECAY KINETICS OF TRIPLET STATES AND RADICALS OF FL AVINS IN THE BOVINE LENS STUDIED BY LASER FLASH PHOTOLYSI S

A.S. Tatikolov1, P.P. Levin1, N.B. Sultimova1, I.G. Panova2

1 - N.M. Emanuel Institute of Biochemical Physics RAS, Moscow, Russia 2 - N.K. Koltsov Institute of Developmental Biology RAS, Moscow, Russia

tatikolov@sky.chph.ras.ru

The mammalian lens represents the complex aqueous colloidal system generally consisting of proteins named crystallins. Its content can reach values up to 70% of the total mass of the bio-tissue. The interaction between crystallins is one of the reasons for their ordering, which seems to be important for the lens transparency, and this nanoscale ordering affects physical micro-parameters of protein medium. The microcharacteristics of the lens medium, in particular, peculiarities of molecular diffusion, were studied by various methods such as dynamic light scattering and kinetic experiments with fluorescent probes. Riboflavin seems to be an interesting kinetic photochemical probe of natural protein media since it is present in the lens and probably assists its photodegradation. Riboflavin and its derivatives, for example, flavin mononucleotide, absorbing light in the visible region, are efficient photosensitizers of oxidation processes. It is supposed that the studies of kinetic behavior of flavin triplet states and radicals directly in the lens medium can give new information about its structure and microcharacteristics. In the present work the kinetics of fast reactions of riboflavin (RF) and flavin mononucleotide (FMN) were studied by the laser flash photolysis technique in bovine lens (L) and its aqueous solutions. The photoexcitation of aqueous solutions of Rf and FMN at neutral pH results in the formation of the triplet excited states of riboflavin (3Rf) and flavin mononucleotide (3FMN). The addition of L results in the acceleration of 3Rf and 3FMN decay and the formation of corresponding RFH• and FMNH• (рКа = 8.3) radicals. It was found that the rate constant of radical decay only slightly increased in the course of L dilution by water up to 50%, but then the sharp acceleration of radical decay is observed after further dilution above 50%. It seems that such behavior can be explained in terms of the variations of the protein medium nanostructure. The dependence obtained correlates well with the data on light scattering. At the same time it was shown that, in spite on high apparent viscosity, the kinetics of RfH• и FMNH• radicals decay in aqueous solutions of collagen and hyaluronic acid, or in the hen egg-white, is similar to that in water. The effects of globulation and nanostructural features of protein media on reaction kinetics of small probe molecules are under the discussion. The financial support from the Russian Foundation for Basic Research (project 09-04-01054a) is acknowledged.

160

FLUORESCENCE RESONANCE ENERGY TRANSFER AND COMPLEX FORMATION BETWEEN CYANINE DYES AND DNA

A.S. Tatikolov, P.G. Pronkin

N.M. Emanuel Institute of Biochemical Physics RAS, Moscow, Russia

tatikolov@sky.chph.ras.ru

Noncovalent interaction of dyes and related compounds with various biomacromolecules has been the subject of numerous studies, since it forms the basis for occurrence in vivo of a variety of photochemical processes [1] and, thus, makes it possible to use dyes both in biomedical studies as DNA labels and in clinical practice [2, 3]. In this respect, polymethine (cyanine) dyes are of particular interest [4]. Owing to the high sensitivity typical for fluorescent analytical techniques, fluorescence resonance energy transfer (FRET) attracts the rapt attention of researchers [5 – 8]. In the present work FRET was studied between carbocyanine dyes in noncovalent complexes with DNA. A DNA molecule used as a rigid matrix for the dye molecules embedded, which facilitated the energy transfer due to the drawing together the molecules of the donor and acceptor dyes. Polymethine dyes 3,3'-9-triethyl-5,5'-dimethyloxacarbocyanine iodide (donor) and 3,3'-diethylthiacarbocyanine iodide (acceptor) were used for the intermolecular FRET investigation in complexes with DNA. The experiments were carried out in a wide range of DNA concentrations (10–6 – 5 x 10–4 M). It was found that in the range of low concentrations of the biopolymer (< 5 10–5 M) the FRET efficiency (r) remained constant (0.44 ± 0.01). The subsequent increase in the DNA concentration led to a decrease in r (to 0.23 ± 0.02, cDNA = 4.9 x 10–4 M). The experimental data were interpreted in terms of both the dye–DNA stoichiometric complex and the pseudophase model. The latter model was shown to describe adequately the experimental results. [1] A.N. Glazer, H.S. Rye. Nature 359 (1992), 859. [2] E.S. Voropay, M.P. Samtsov, A.P. Ludovsky, A.N. Sevchenko. Proc. SPIE – Int. Soc. Opt.

Eng. 4749 (2004), 221. [3] B.P. Matselyukh, S.M. Yarmoluk, A.B. Matselyukh, V.B. Kovalska, I.O. Kocheshev, D.V.

Kryvorotenko, S.S. Lukashov. J. Biochem. Biophys. Methods 57 (2003), 35. [4] E. Delaey, F. van Laar, D. De Vos, A. Kamuhabwa, P. Jacobs, P. de Witte. J. Photochem.

Photobiol. B: Biol. 55 (2000), 27. [5] Laib S., Seeger S. J. Fluoresc. 2004. V. 14. P. 187 – 191. [6] Bunkenborg J., Gadjev N.I., Deligeorgiev T., Jacobsen J.P. Bioconjug. Chem. 2000. V. 11. P.

861 – 867. [7] Bunkenborg J., Stidsen M.M., Jacobsen J.P. Bioconjug. Chem., 1999. V. 10. P. 824 – 831. [8] Clegg R.M., Murchie A.I.H., Zechel A., Lilley D.M.J. Proc. Natl. Acad. Sci. USA. 1993. V.

90. P.2994 – 2998.

161

REACTIONS OF PHOTOINDUCED AND THERMAL RECOORDINATION IN OPTICAL MOLECULAR SENSORS

E.N. Ushakov1, S.N. Dmitrieva2, A.I. Vedernikov2, L.G. Kuz’mina3,

A.Ya. Freidzon2, M.V. Alfimov2, S.P. Gromov2

1 - Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia 2 - Photochemistry Center RAS, Moscow, Russia

3 - N.S. Kurnakov Institute of General and Inorganic Chemistry RAS, Moscow, Russia en-ushakov@mail.ru

Interest in the reactions of recoordination in the complexes of metal cations with the ligands having a donor-acceptor chromophore arose in the connection with the development of optical molecular sensors [1–3]. The photoinduced disruption of coordination bonds in the complexes involving ionochromic azacrown compounds is most widely investigated. The mechanism of the photoinduced recoordination is not yet clearly understood. In some works it is asserted that the photoinduced disruption of the N---Mn+ coordination bond is followed by the complete dissociation of the complex, i.e. the metal cation is released from the macrocycle cavity into solution during the excited state lifetime [4]. However, this interpretation in some cases disagrees with the known data on the kinetics of complex formation reactions. Previously we supposed that the complexes of some ionochromic crown compounds with metal cations can undergo the recoordination reaction not only in the excited state but also in the ground state [5].

That is the complex of 1:1 composition in the ground state can exist as two thermodynamically equilibrated forms (like А and В in the scheme). However, until recently there were no solid experimental evidences for this hypothesis. In this report we will discuss the mechanisms of photoinduced and thermal recoordination, as well as the kinetic aspects of cation–macrocycle interactions. In addition, new experimental data will be presented that conclusively prove the possibility for the thermal recoordination to occur in the complexes involving ionochromic crown compounds. This work was supported by the Russian Foundation for Basic Research and RF Ministry of Science and Education. Literature: [1] M.M. Martin et all, Chem. Phys. Lett., 1993, 202, 425-430; [2] P. Dumon et all, J. Phys. Chem., 1994, 98, 10391-10396; [3] V. Van den Bergh et all, Biophys. J., 1995, 68, 1110-1119; [4] C. Ley et all, ChemPhysChem, 2009, 10, 276-281; [5] E.N. Ushakov et all, Izv. AN, Ser. Khim., 1997, 484-492.

162

INFLUENCE OF THE SOLVENT ON THE RADIUS OF ELECTRON-EXCHANGE INTERACTIONS

OF d0 METAL COMPLEXES WITH CYCLOPENTADIENE

V.P. Vasiliev, G.V. Loukova, V.A. Smirnov

Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia vpvasiliev@mail.ru

A great number of chemical reactions and interactions occur in solutions, therefore one of most important problems is resolution of relationship between chemical reactivity and medium properties, solvent effects, and pairwise solvent – solute interactions. Earlier, we demonstrated that triplet – triplet radiationless energy transfer from metallocenes Cp2MCl2 (M = Zr, Hf) to catalysts substrates (olefins and/or dienes) in glassy solutions, made of non-specific solvent methylcyclohexane, can be well described in terms of the Perrin equation viz. Ф0/Ф = exp(N·V·[A]) (where Ф0 and Ф denotes the emission quantum yield in the absence and in presence of the emission quencher, V stands for the volume of a quenching sphere of the radius R (in cm), N = 6.02·1020, and A is the emission quencher concentration). In the present work, influence of a solvent on effectiveness of electron-exchange resonant energy transfer from d0 organometallic complexes to non-phosphorescing cyclopentadiene was studied in glassy organic solvents at 77 K. It should be noted that concentration dependences of phosphorescence quenching of metallocene complexes Zr and Hf in glassy media obey well the Perrin equation. Radius of radiationless energy transfer was revealed to be affected by solvation of the metal complexes of the studied series. Thus, for instance, the critical radius of electron-exchange energy-transfer sphere drastically decrease (for 2–3 Å, i.e. for 15–20%) with enhance in the energy-donor solvation effectiveness upon other equal conditions. Besides, dependence of R0 on solvent properties remains the same on going from hafnium to zirconium complexes and upon the ligand sphere modifications. Interestingly, values of the critical radius of triplet – triplet energy-transfer sphere are virtually the same (within the error limits for R0), regardless the difference in transition metal ion (Zr or Hf) in isostructural complexes. In summary, the results obtained allow us to assume that the critical radius of triplet – triplet energy-transfer sphere appers to be quite sensitive toward changes in the composition of solvent shells around photoexcitation energy-donor molecules. Acknowledgements. The authors express their gratitude to Professor A.E. Shilov for fruitful discussion and Dr. W. Huhn («Procter & Gamble Italia») for a kind loan of single-crystalline samples of rac-С6H10(IndH4)2ZrCl2. This work was financially supported by Russian Academy of Sciences and Russian Foundation for Basic Research (project N 09-03-00379).

163

FTIR EVIDENCE FOR LEWIS ACIDITY INDUCED BY ADSORPTIO N

K.V. Voronina, A.A. Tsyganenko

V.A.Fock Institute of Physics, St.Petersburg State University, Russia tsyg@photonics.phys.spbu.ru

Strength of surface sites of oxide catalysts is known to depend on the presence of dopants or preadsorbed molecules. Brønsted acidity of silanol groups of silica was shown to increase after adsorption of such acids as CO2 or H2S, and addition of SO2 or NO2 even leads to protonation of coadsorbed bases, such as ammonia, pyridine or 2.5-dimethylpyridine (DMP)1. The same effect of induced Brønsted acidity was observed for alumina2 and magnesia3 exposed to H2S. On the other hand, basicity of oxygen atoms of silanol groups measured by adsorbed fluoroform, increases greatly in the presence of bases4. One could anticipate that interaction of acidic molecules with surface oxygen ions linked to the cations should just the same affect the Lewis acidity of the latter. To check up this supposition we have studied the influence of CO2 and SO2 adsorption on the acidity of CaO, using low temperature CO adsorption as a test. CO adsorption on pure CaO outgassed at 973 K results in the bands of ”carbonite” CO2

2- ions5 together with the bands of molecularly adsorbed carbon monoxide at 2155-2165 cm-1. No other bands were detected at higher wavenumbers. However, if the sample is pre-exposed to CO2, the carbonite bands do not appear and the band of molecularly adsorbed CO shifts up to 2179 cm-1 while after preliminary adsorption of SO2 the highest position of this band at low coverages reaches 2184 cm-1. So high frequencies can hardly be explained by interaction with OH groups. Interaction with the most acidic hydroxyls of zeolites shifts CO band up to 2175 cm-1 only6. Unlike MgO3, CO adsorption on CaO pre-exposed to CO2 or SO2 is not accompanied by OH band perturbation and adsorption of DMP does not lead to characteristic bands of protonated base molecules. For CaO outgassed at 773 K or exposed to H2O at 300 K surface concentration of OH groups is much higher, however, after adsorption of CO2 or SO2 the intensity of the high-frequency CO bands is lower that for the sample treated at 973 K. Thus, we assign the high-frequency CO band to molecules coordinately bound to surface cations, whose electron-accepting ability is enhanced as a result of CO2 or SO2 adsorption. Effect of weakly adsorbed electron-accepting molecules upon the strength of cationic sites can be explained as a result of electron density shift from the cation towards the molecule. In our case chemisorbed CO2 or SO2 exist in the form of surface carbonate or sulfite ions, and one can even consider the surface as a layer of corresponding salt. The results, thus, infer higher electron accepting ability of cations in salts as compared with oxides. In the electrostatic model the increased frequency shift of adsorbed CO reflects the higher electrostatic field of the cation surrounded by larger anions when O2- ions are transformed to CO3

2-, etc. This effect is consistent with superacidity of zirconia doped with SO4

2- anions7. The highest acidity, close to that of naked cations, is not by chance observed for cationic zeolites, where the negative charge is distributed over the whole polyanionic alumosilicate framework. CO adsorption on such systems reveals linkage isomerism9, which could be, thus, also anticipated for salts or oxide surfaces modified by adsorption of acids. Experiments for the search of this effect are in progress.

The work was supported by RFFI, grant 06-03-32836a.

References: [1] Tsyganenko A.A., Storozheva E.N., Manoilova O.V. Catal. Today, 70 (2001) 59. [2] Travert A., et al. J. Phys. Chem. B, 106 (2002) 1350. [3] Oliviero L., et al. Industrial & Engineering Chemistry Research., 48 (2009) 1237 [4] Storozheva E.N., Sekushin V.N., Tsyganenko A.A. Catal. Letters. 107 (2006) 185. [5] Babaeva M.A., Bystrov D.S., Kovalgin A.Yu., Tsyganenko A.A. J. Catal., 123 (1990), 396. [6] Otero Areán С., et al. Eur. J. Inorg. Chem., 2001, 1739. [8] Ivanov A.V., Kustov L.M. Rossijskij Khimicheskij Zhurnal. 44 (2000) 21. [9] Otero Areán C., Turnes Palomino G., Tsyganenko A.A., Garrone E. Intern. J. Mol. Sci., 3 (2002) 764.

164

SYMPOSIUM “FUNDAMENTAL PRINCIPLES OF NANOPHOTONICS”

ORALS

OBTAINING, PROPERTIES AND PERSPECTIVES OF COLLOIDAL QUANTUM DOTS

S.B. Brichkin, M.G. Spirin, D.Yu. Nikolenko, V.Yu. Gak, V.F. Razumov

Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia brichkin@icp.ac.ru

Quantum dots (QD) are nanoobjects which optical and electronic properties depend on their size because of quantum confinements for charge carriers. QD are perspective for wide practical applications in solar sells, light emitting diodes, optical sensors, lasers, elements of optical memory, medicobiological diagnostics et al. In this report the results of experimental investigations of different size effects in semiconductor QD and metal nanoparticles (NP), obtained by methods of micellar and high temperature colloidal synthesis are represented. The formation of NP in reverse micell solutions (RV) occurs in water pools and is controlled by intermicellar exchange. Water pools are nanoreactors, in which particles are formed, and micellar shells stabilize them. The NP size can be governed by changing the water pool size. Different NP both of individual (AgHal, CdS, CdSe, RuS2, γ-Fe2O3) and complex compositions were obtained by using this method. At the formation of NP with core-shell structure (AgBr@AgI) it was established that in the case of epitaxial growth the affinity of crystal structures of core and shell is of great importance. At the synthesis of β-AgI NP the effect of water structuring was found. The formation of NP in RV is substantially defined by the permeability of micellar shells, which strongly depends on the hydrocarbon chain length of the organic solvent. Hydrocarbons with short chain more efficiently slow down the rate of NP growth, and in large micelles molecules of hydrocarbon solvent penetrate into micellar shell better. The methods of NP size stabilization were developed. At the synthesis of gold NP it was shown that by changing of experimental conditions (surfactant or reducing agent type) it is possible to vary considerably the size features of NP, and to obtain not only spherical particles of different size and size distribution, and also NP of anisotropic shape. In the method of high temperature colloidal synthesis we proposed a new approach to realization of the NP size distribution “focusing” regime by controllable temperature reducing. By using this approach CdSe, CdTe NP of different sizes with tunable spectral properties were obtained, and core-shell NP CdSe@ZnSe with high luminescent efficiency (up to 60%) were synthesized. New effective technique for synthesis of CdSe NP with high yield of tetrapod shape without any additional size and shape selection was developed. The availability of “spin- coating” method for the formation of ordered monolayers of polystyrene latex particles (LP) was shown. The sizes of ordered domains reached several hundreds of nanometers, and LP in the ordered domains were packed in cubical or hexagonal lattices, with structure of grooves and dimples. This structure was used for the ordering of spherical silver NP (dср=20 nm) into the linear chains. Such ordering results in cardinal changes in absorption spectrum of ordered silver NP in comparison with spectrum of free state silver NP, in solution. The technique of controllable etching of ordered LP monolayers in the oxygen plasma was realized. This method opens up extensive possibilities for nanolithography.

This work is financially supported by Program of Fundamental Research RAS 27 “Basic fundamental research in nanotechnology and nanomaterials”, and Russian Foundation for Basic Research (project 07-03-00397).

165

SEMICONDUCTOR QUANTUM DOT MOLECULE PHOTOLUMINESCENCE MEDIATED BY

INCOHERENT REVERSIBLE ENERGY TRANSFER

A.V. Fedorov, A.V. Baranov, S.Yu. Kruchinin, A.V. Savelyeva, M.V. Mukhina

St.Petersburg State University of Information Technologies, Mechanics and Optics, Russia a_v_fedorov@inbox.ru

One of the basic problems of low-dimensional physics is the energy transport of elementary excitations in nanostructures and particularly the nonradiative energy transfer between semiconductor quantum dots (QDs). The problem is especially important for one-, two-, and three-dimensional structures with enough close-packed arrangement of QDs, i.e. when an interdot distance is equal in order of value or less than the QD size. Among such structures are the quantum dot molecules, chains, rings, two- and three-dimensional arrays as well as the dendrites based on QDs. For small interdot distances the interaction between QD electronic subsystems becomes the governing factor determined a lot of physical properties of QD ensembles. The interaction can lead to both the incoherent and coherent processes of energy transfer between QDs. Presence or absence of the coherent effects in energy transfer from a QD-donor of energy to a QD-acceptor of energy is determined by the relation between the transfer rate DAγ and the dephasing rate DAΓ for this transition. If DADA γ>>Γ , then the incoherent energy transfer takes place; otherwise the coherent effects will influence essentially on the energy transport between QDs. For incoherent energy transfer it should be separated two cases that differ from each other by the relation between DAγ and the intraband energy relaxation rate Aγ

for QD-acceptor. If DAA γγ >> , then the energy transport will be irreversible. If Aγ is equal in

order of value or less than DAγ , then some portion of the energy will come back from the QD-

acceptor to the QD-donor. Experimental data [1-4] show that Aγ can vary in value from 108 s-1

to 1013 s-1. Since DAγ may be as much as 1012 s-1 [5] it should be expected that both the incoherent reversible and coherent energy transfer can be realized for real QD systems. Hence an investigation of both the processes is problem of current importance. Energy transfer should be manifested for optical spectra of interactive QDs. It has been observed for QDs of different types in the photoluminescent experiments in frequency and time domains. Despite a lot of theoretical works devoted study of different aspects of energy transport in QDs, the consistent description of QD secondary emission spectra taking into account the energy transfer process has not been developed up to now. In present work based on our previous results [5] the theory of stationary photoluminescence for semiconductor quantum dot molecule with the incoherent reversible energy transfer is developed and the essential features of corresponding spectra allowing to distinguish the energy transfer regimes using experimental data are discussed. 1. C. Bonati, A. Cannizzo, D. Tonti, Phys. Rev. B 76, 033304 (2007). 2. P. Guyot-Sionnest, B. Wehrenberg, D. Yu, J. Chem. Phys. 123, 074709 (2005). 3. K. Ikeda, H. Sekiguchi, F. MinamiIkeda, J. Lumin. 108, 273 (2004). 4. R. Heitz, H. Born, F. Guffarth, et al., Phys. Rev. B 64, 241305 (2001). 5. S.Yu. Kruchinin, A.V. Fedorov, A. V. Baranov et al., Phys. Rev. B 78, 125311 (2008).

166

MOLECULAR DESIGN OF LIGHT-SENSITIVE NANOSIZED SYSTE MS BASED ON UNSATURATED AND MACROCYCLIC COMPOUNDS

S.P. Gromov1, E.N. Ushakov2, A.I. Vedernikov1, L.G. Kuzmina3, M.V. Alfimov1

1 - Photochemistry Center RAS, Moscow, Russia

2 - Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia 3 - N.S. Kurnakov Institute of General and Inorganic Chemistry RAS, Moscow, Russia

spgromov@mail.ru

A new trend is being currently formed in nanotechnology, namely, organic nanophotonics. We propose a new unique class of polyfunctional light-sensitive compounds: crown-containing unsaturated dyes functioning as photochromes, fluorophores and ionophores. A large body of research has been performed for their synthesis, determination of their spatial structures, study of self-assembly features to give nanosized systems, and also study of fluorescent, photochemical and complexing properties. Resulting from the research, we elaborated for the first time universal molecular meccano, allowing one to accomplish building-up, with using a limited number of complementary compounds, light-sensitive and light-emissive nanosized systems of varied architecture with adjusted properties. Within the same class of compounds one can construct in solution, solid and at the air-water interface new types of molecular switches, photocontrolled molecular machines, photosensitive monolayers and monocrystals susceptible to all of the key photoprocesses.

molecular devicesmolecular machines

cucurbituril

hνννν

PHOTOANTENNA

displacement

hνννν

CROWNPHOTOANTENNA

M n+

The high practical value of these studies deserves attention. They provide a new strategy for the design of materials for nanophotonics, which was demonstrated, first of all, by the creation of practically important sensor and photochromic materials. This work was supported by the Presidium and the Division of the RAS, the Ministry of Science and Education, the Russian Foundation for Basic Research, the Moscow Government, the INTAS, the CRDF and International Science Foundation (ISF), the DFG, and the Royal Society.

167

AOT/WATER/HEXANE REVERSE MICELLES AS “MICELLAR SIEVE S” FOR CYANINE DYE J-AGGREGATES

A.V. Ivanchikhina1, L.M. Nikolenko2

1 - Moscow Institute of Physics and Technology

and Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia 2 - Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia

Ivanchihina@gmail.com

During the past decade J-aggregates have attracted the interest of several research groups, due to their peculiar structural and photophysical properties which make them potential candidates for applications in nonlinear optics, nanometre-sized photoconductors and light harvesting systems. The preparation of monodispersed nanometer-sized J aggregates is of great practical importance. One of possible ways of solving this problem seems to be the use of reverse micelles. We investigate the behavior of J-aggregates of a cyanine dye, 3,3’-di-(γ-sulfopropyl)-4,5,4’,5’-dibenzo-9-ethylthiacarbocyanine betaine pyridinium salt, in AOT/water/hexane reverse micelles (W = 2–50), both during the course of rapid microemulsion formation and then after stabilization of the microemulsions at thermodynamic equilibrium. We obtained the time evolution of the absorption spectra of DEC in micellar solutions for W varied over the range 2–50. The time-resolved spectra show that DEC is present in the form of J-aggregates already at the earliest stages after mixing when the micellar structure has not yet been formed. After aggregation, some dye J-aggregates decompose into trans-monomers, and the fraction of such J-aggregates diminishes with increasing W. Since in our experiments W was varied on change in the AOT concentration, it can be inferred that the amount of monomers formed in the system grows with increasing [AOT] (decreasing W). The absorption spectra of as-prepared solutions with different W show that with increasing W, the intensity of the J-band is seen to grow while that of the M-band, to decrease. The temporal behavior of J-aggregates in the micellar system also depends on W. The observed spectral changes can be related only to precipitation of J-aggregates. The amount of precipitated aggregates diminishes with increasing W. The obtained data enabled us to explain (for the first time) the formation mechanism of the J-aggregates of cyanine dye in micellar solution and their temporal behavior. The processes defining the above dependencies were found to take place prior to attaining equilibrium in microemulsion and are as follows: Formation of J-aggregates in the aqueous macrophase; Deaggregation of J-aggregates on interaction with AOT molecules penetrated into the aqueous macrophase. The AOT molecules already built-in into the micelle shells (which is typical of stable microemulsions) cannot cause the deaggregation; Encapsulation of the J-aggregates (by RMs) whose sizes are smaller than those of water pools and displacement of larger aggregates into the organic phase where they get gradually consolidated and then precipitated. In view of this, micellar solution can be compared with a sieve for selection (i.e., by leaving in suspended state) and stabilization of aggregates with a desired size, the value of W defining the upper size limit for J-aggregates that are sifted out by the micellar sieve. It was shown that the only possible way to introduce dye into micellar solution through the aqueous phase (even at elevated temperatures) fails to distribute dye monomers among micelles with subsequent J-aggregation via intermicellar exchange. This is because the J-aggregates of cyanine dye are formed in the aqueous macrophase prior to formation of RMs. Hence the mechanism based on intermicellar exchange and applicable to formation of inorganic nanoparticles and porphyrin J-aggregates is inapplicable to the system under study. This work is financially supported by Program of Fundamental Research RAS 27 “Basic fundamental research in nanotechnology and nanomaterials” .

168

DELAYED FLUORESCENCE ANNIHILATION KINETICS CHANGE BY RECONSTRUCTION OF POLYMERIC CHAIN STRUCTURE IN

SOLID SORBENT CAVITIES AND ON NANOPARTICLE SURFACES

M.G. Kucherenko, S.V. Izmodenova, N.Y. Kruchinin

Orenburg State University, Russia rphys@mail.osu.ru

When some functional nanodevices building problems are appear, the macromolecule chain conformation characteristics determination is required often in sorbent cavities or on disperse nanoparticle surfaces. A polymeric chain, containing photoactive centres in its structure and adsorbed by nanocavity walls is one of the perspective functional nanosystem. If molecules, presenting itself such centres, adsorbed by the chain on its length uniform, the spatial distribution behavior of their concentrations will repeat the density averaged profile of polymeric subunits. The non-uniform molecules spatial distribution renders an essential influence upon a kinetic mode formation of reactions with the molecule participation in the nanoarea. At the detailed description of a photo-reactions kinetics in nanosystems and decryption of accompanying luminescent signals it is necessary to take into account the radial profile of polymeric sections. In this work we used an analytical expression that found earlier (Kucherenko M.G., Chmereva T.M., 2008) for the spatial sections distribution of the polymeric chain, adsorbed by spherical nanocavity walls. Another expression for the like distribution on surfaces spherical nanoparticle is received. Besides, on example of 70-section lyzocime fragment a molecular-dynamic modeling of the section density radial profile is realized for the comparison with analytical dependencies. A mathematical model of the cross-annihilation kinetics of organic molecules triplet (Т) excitations with molecular oxygen 1

g∆ -excitations is offered for the cases of

nanopores and nanoparticle colloidal solutions with macromolecular chains "edge of a forest". The cross-annihilation delayed fluorescence pulse form ( )T

DFI t∆ was defined on the base of the Т-

centres concentration distribution ( , )Tn r t and the oxygen molecule excitation distribution

( , )n r t∆

2

0

( ) ~ ( , ) ( , )4TDF TI t n r t n r t r drπ

∞∆

∆∫ .

Time dependencies of the dye cross-annihilation delayed fluorescence intensity ( )T

DFI t∆ in nanopores with different radius R

Satisfactory agreement between theoretical kinetic curves and experimental cross- annihilation delayed fluorescence intensity signals of xantene dyes in porous sorbents is observed.

This work was supported by the Russian Foundation for Basic Research (project no. 08-02-99035- r2006_ofi) and the Ministry of Education and Science of the Russian Federation (assignment no. 1.3.06 from the Federal Agency of Education).

169

THE FEATURES OF THE RECOMBINATION PROCESSES INTO THE PYROLYTIC CdS FILMS

T.L. Maiorova, V.G. Klyuev, M. Pham Thi Hai, V.S. Bikovskaya

Voronezh State University, Russia

mtl084@yandex.ru

Keywords: the photoconductivity, CdS, the photomemory effect The subject of our investigations is the photoelectrical properties of the pyrolytic CdS films, alloyed by alkaline metals. So there have been determinated that

1. the pyrolytic CdS films have enough high quantum yield of photoluminescence~ 1 % at the room temperature;

2. the alloying of CdS pyrolitic films by alkaline metals results in the multiplying of luminescence intensity by 3 ÷ 5 as against the pure ones;

3. the photoluminescence of such films are stable to influence of the ultraviolet irradiation during long time;

4. the investigated structures have the long relaxation of photocurrency (the photomemory) (t ~ 103 – 104 c) at room temperature.

The photomemory effect is due to inhomogeneous structure of the samples containing potential barriers between low- and high-resistance regions. The latter debars the recombination of nonequilibrium carriers. The doping of alkaline metals, for example Cs, is due to the presents of Cs+

i defects and the increase of the number of V+

S, Cl+S defects. In virtue of these the difference between low- and high-resistance regions diminishes at large impurity concentration, the potential barrier responsible for the stored photoconductivity decreases. At this the whole recombination is faster then the one for the films with small concentration of the impurity, though it saves the character of the stored photoconductivity. By means of the thermally stimulated conductivity technique, information on the energy levels of electron traps in pyrolytic CdS films was obtained. It has been shown, that the observed thermal stimulated conductivity may be due to not only the present of the electron localization levels, but their interaction with the potential barrier responsible for the stored photoconductivity. In the results of the recombination processes investigations, we have constructed the energy model of the levels in the band-gap of the pyrolytic CdS films, alloyed by alkaline metals. The observed properties are practically important for the using of the investigated structures as solar cells, radiation sources or radiation detectors in devices designed to have stable parameters in radiation fields. The results of the investigation allow to optimize the synthesis technology of CdS pyrolytic films with controllable properties, in particular, for the use of such structure as photomemory elements. Furthermore the pyrolytic CdS films are interested not only for the applied aspect but for the fundamental investigations of the recombination processes into such structures.

170

LUMINOPHORE-CONTAINING MONODISPERSE POLYMERIC NANOPARTICLES: DESIGN, SELF-ASSEMBLING,

AND APPLICATION FOR CHEMISENSORICS

A.Yu. Menshikova1, N.N. Shevchenko1, T.G. Evseeva1, A.V. Yakimansky1, V.A. Sazhnikov2, A.V. Koshkin2, M.V. Alfimov2

1 - Institute of Macromolecular Compounds RAS, St.Petersburg, Russia

2 - Photochemistry Center RAS, Moscow, Russia asya@hq.macro.ru

Modern polymer science has developed methods to prepare monodisperse polymeric particles from 30 nm up to 10 µm in diameter. These particles are of great interest for nanotechnology, since their self-assembling from dispersions is a promising way to design of novel materials with hierarchic structures. Thus, 3D-ordered arrays of submicron particles demonstrate photonic band gap (PBG) in the spectral range of visible or near IR light, which are of importance for optoelectronics. Moreover, in the ordered arrays built up by dye-containing uniform particles, absorption or emission spectra remarkably changes in the PBG vicinity, which can be used in various applications. The dye-containing particles can also serve as sensing elements, if dyes in their surface layers ensure optical response to various analytes in contacting liquid or gas phases due to their complexation with the dyes. Hence, there is a drive to develop new methods for surface modification of monodisperse polymeric particles with dyes forming sensing sites. Monodisperse polymeric particles were synthesized by heterophase copolymerization of styrene and methacrylic acid and ion-exchange of cationic chromophores (Rhodamine 6G, Nile Red) on the negatively charged particle surface was carried out. Poly(methyl methacrylate-co-N-vinylformamide) particles were prepared in the presence of β-cyclodextrin, which localized on the particle surface and formed inclusion compounds with some dyes. Besides, surface of poly(styrene-co-N-vinylformamide) particles were hydrolyzed, forming aliphatic amino groups in N-vinylformamide units, which were used for Fluorescein isothiocyanate covalent binding. Alternatively, core-shell monodisperse particles were prepared by seeded dispersion copolymerization, adding dye-containing comonomers along with cross-linkers at the last step to incorporate them into particle shells. To enhance the selectivity of the interaction between dyes and analytes, molecular imprinting technique was applied. For this purpose, seeds were swollen with comonomers and a molecular template (methanol, ethanol, acetone, or toluene), removing one after polymerization. This approach allowed generating robust and selective synthetic receptors for recognition of small molecules in the particle surface layer. Effects of the methods of dye incorporation on fluorescence spectra of particle arrays and their changes in the presence of volatile analytes were revealed. Obtained results showed a good promise of arrays built up with dye-containing polymeric particles as sensing elements for gas chemisensors. The work is supported by the Federal Agency on Science and Innovation of the Russian Federation (contract 02.513.12.3025) and by the Scientific Program “Basic research of nanotechnology and nanomaterials” of the Presidium of the Russian Academy of Sciences.

171

MOLECULAR DYNAMICS SIMULATIONS OF AN AOT REVERSE MICELLES SELF-ASSEMBLY

A.V. Nevidimov

Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia

nevidimovsasha@yandex.ru

Molecular dynamics is a powerful technique for investigation nanoscale molecular systems such as biological molecules, nanoparticles, and polymers. In particular, molecular dynamics simulations are employed to study reverse micelles structure in atomic detail. Reverse micelles are formed in nonpolar solutions of certain amphiphilic molecules. Due to ability to dissolve considerable water amounts reverse micelles are widely used in chemical and biochemical catalysis as well as in narrow size distribution nanoparticles synthesis. The latter application is because of narrow size distribution of reverse micelles themselves. At that the structure of the reverse micelles defines the shape and size of nanoparticles synthesized, and therefore it is necessary to know reverse micelles structure in molecular detail. Molecular dynamics simulations of reverse micelles are usually performed on pre-assembled micelles as initial geometry. But experimental information about micellar size and composition is needed to prepare initial micelle. If this information is unavailable, it is impossible to carry out computing experiment or its results may depend on the initial conditions. Recently it is possible to study reverse micelles self-assembly processes in systems that contain components distributed randomly at start geometry. In this work molecular dynamics simulation technique was used to explore reverse micelles formation in the three-component system containing water, hexane, and AOT (sodium bis-2-ethylhexyl-succinosulfonate). Water and AOT molecules were described at atomic level, but each hexane molecule was reproduced by simple van der Waalse pseudo-atom. Such different molecules representation increases computational effectiveness in several times, and allows receive structural information about reverse micelles in atomic detail. It has been found typical time scale of molecular dynamics simulation of reverse micelles self-assembly in hexane is at least 50 nanoseconds. And it is viscosity of hexane that defines this feature. For example, reverse micelles self-assembly processes in solvent supercritical carbon dioxide require only 5 ns for time scale. In this work it has been investigated influence initial parameters of systems (such as water and AOT concentrations, and starting component distribution – in all, 5 different systems) on molecular dynamics simulation results: namely, reverse micelles structure, their shape, size, components distribution, and surface area per one AOT molecule. It was revealed that micelles shape tends to sphere in a wide range of AOT and water concentrations. If micelle shape assume to be ellipsoidal with main semi-axes a, b, and c (a > b > c) than ratios c/a were found to be between 1 and 0.8 for all micelles. The partial density of water was found to be approximately 1.0 g/cm3. The surface area on micelle core covered by one AOT molecule varies in the range of 60 and 80 Å2. All parameters found have no dependences with initial conditions of modeling, and were found to be in good agreement with available experiment data. That is why molecular dynamics simulation of reverse micelles self-assembly is a forward-looking technique for investigation of reverse micelles in atomic level detail. This work was supported by the Russian Foundation of Basic Research (project no. 07-03-00397a) and the Program of Fundamental Research RAS no. 27 “Basic of fundamental research in nanotechnology and nanomaterials”.

172

SUPRAMOLECULAR ENSEMBES OF Ru(II) PHTHALOCYANINATE, NONLINEAR OPTICAL AND PHOTOREFRACTIVE PROPERTIES

L.Ya. Pereshivko, A.V. Vannikov, A.D. Grishina,

V.I. Zolotarevsky, Yu.G. Gorbunova, Yu.Yu. Enakieva, T.V. Krivenko, V.V. Savelyev, A.Yu. Tsivadze

A.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia

van@elchem.ac.ru

Principal direction of our works is the elaboration of the photorefractive (PR) composites based on polymers having high glass transition temperature Tg. The high Tg polymers improve the stability of composite characteristics but require the use of the nano-dimensional nonlinear optical chromophores (NLO). Indeed, the chaotic orientation of any sizes dopants is frozen in the polymers with high Tg and therefore the possibility of orientation polarization of NLO chromophores is eliminated, the second order nonlinearity goes to zero but the third-order susceptibility has a nonzero value: χ(3) = Nγ f4<cos4ξ>. Here N is the concentration of the chromophores, γ is the third-order molecular polarizability, f = (n0 + 2)/3 is the Lorentz field factor. The mean value of <cos4ξ> equals 1/5 at a random distribution of orientation angles ξ of NLO chromophores. The third order susceptibility increases with the increase of the exciton delocalization length and achieves the highest values for nano-dimensional formations. Nano-dimensional chromophores have the long-wavelength optical absorption and were used as spectral sensitisators to near IR region. The polymer composites consisting of polyvinylcarbazole (PVK) and ruthenium(II) tetra-15-crown-5-phthalocyaninate with axially coordinated molecules of triethylenediamine (R4Pc)Ru(TED)2 and ethylisonicotinate (R4Pc)Ru(EIN)2 as NLO chromophores and also as spectral sensitisators to wave-lengths 1064 nm and 1550 nm, correspondingly, are concerned. Photorefractive polymer layers were cast from the tetrachloroethane solution of the components. The better results were achieved after 4 cycles of heating of the Ru(II) complexes solution to 70oC and slow cooling to room temperature. The two-beam coupling gain coefficient of polymer composite containing (R4Pc)Ru(TED)2 equals Γ = 140 cm–1 and net gain coefficient Γ– α = 102.3 cm–1 at E0 = 100V/µm and 1064 nm (α is coefficient of optical absorption). Composites based on (R4Pc)Ru(EIN)2 reach Γ = 48.3 cm–1 or Γ - α = 42.3 cm–1 at E0 = 100V/µm and 1550 nm. Optical absorption of the fresh tetrachloroethane solutions of complexes have maximum at 626 - 627 nm and longwave boundary near 900 - 1000 nm but spreads out to 1400 nm for (R4Pc)Ru(TED)2 and to 1650 nm for (R4Pc)Ru(EIN)2 in result of 4 cycles of heating to 70oC/slow cooling of the solutions. It was supposed that this spreading arises from the formation of supramolecular ensembles of the complexes. To argue this suggestion, the images of supra molecular ensemblies of the (R4Pc)Ru(TED)2 has been obtained with method of atomic force microscopy. The image of the fresh sample contained cylindrical particles from 50 to 100 nm in diameter and the mean height

of the cylinders was about 2-3 nm. Shown in left Figure the image of the sample fabricated after heating demonstrates stable supramolecular wires of 7-8 nm in height, 100 (1) – 150 (2) nm in width and 600 nm (3) or more in length.The positive sign of the third order susceptibility were measured in the solutions of (R4Pc)Ru(TED)2 complexes with z-scan method. The molecular polarizability of the complexes is about γ = 4.5×10–32 esu. The polarizability attributed to one molecule increases by factor of 3.6 when the individual molecule transfers into a supramolecular ensemble.

This work was supported by the ISTC (Grant No. 3718) and RFBR (projects No. 07-03-13547, 08-03-00125 and 08-03-00835).

173

POLARISATION ANISOTROPY OF SINGLE-CRYSTAL OPAL FILM S

A.I. Plekhanov, V.P. Chubakov, P.A. Chubakov

Institute of Automation and Electrometry SB RAS, Novosibirsk, Russia fractal@iae.nsk.su

In this reports we have studied the polarization anisotropy of photonic crystal (PhC) [1] opal films. These films were prepared from monodisperse spherical silica particles (MSSPs). Diameter of MSSPs was approximately 250 nm. PhCs were obtained by two methods: the moving-meniscus method (MMM) [2, 3] and gravitational sedimentation method (GSM) [4]. In the MMM layers of PhC are formed on inclined substrate along projection (on a substrate) of gravitational force. It produces dedicated direction in PhCs along the line of crystalline growth. The GSM is used for lyophilic suspensions. A layer of lyophilic suspension of MSSPs spread over horizontal substrate evenly where opal structure is forming and drying. Similar films do not have dedicated direction. There are only local irregularities. We have used films with thickness from 1 to 10 µm. Electron microscopy shows that in both methods the single-crystalline films are packed from hexagonal layers of MSSPs. These layers are parallel to substrate and correspond to the crystalline plane [111] of face-centered cubic lattice (FCC). It is known that cubic crystalline systems have the same refractive index in all directions, i.e. the optical indicatrix of FCC have a spherical shape. But our measurements of transmission spectrum in crossed polarizers show that the samples obtained by both methods (MMM and GSM) have (surprisingly) polarization axes. These axes have relation to dedicated directions of PhC films. The films grown by MMM have polarization axis along the line of crystalline growth. The direction of polarization axis for the films grown by GSM depends on the place of measuring because surface tensions have influence on the film forming in GSM. It produces radial irregularities and the local polarization axes are directed along ones. In addition, ellipsometric measurements show that PhC films have birefringence in the plane of the substrate. If these films were filled by some immersion liquid with equal refractive index to silica, birefringence disappears. The difference between the highest and lowest refractive index for the samples prepared by MMM is ∆n ~ 2·10-3. Conoscopy measurements show the following: the indicatrix of refractive index for MMM films is three axial ellipsoid with the angle 2V equals to 17º between optical axes. The axis of indicatrix Ng directs along the line of crystalline growth, Nm lays in the plane of the surface of film and is orthogonal to Ng. The axis Np coincides with normal to the crystalline plane [111]. The axis Np is a bisector of the angle 2V. It shows that the films prepared by MMM are optically negative crystals. The measured differences of refractive index in the plane of indicatrix axes are ng – nm ~ 2·10-3, ng – np ~ 8·10-2. It is a high birefringence and the orientation of indicatrix axes relative to crystallographic axes corresponds to triclinic system. For the first time a high birefringence was found in the PhC films obtained by MMM and GSM. This phenomenon demands an adequate theoretical description and takes into account at the engineering of the elements for photonics. This study was supported by the integration project of the SB RAS 17 and by the Program 8 of Physical Sciences Division of the RAS. 1. K.Sakoda ,“Optical Properties of Photonic Crystals”, Springer-Verlag Heidelberg 2005. 2. Y.V. Vlasov, X. Zh. Bo, J. C. Sturm, D. J. Norris, “Nature, 2001. V. 414. No. 15. P. 289. 3. A.I. Plekhanov, D.V. Kalinin, V.V. Serdobintseva, Russian nanotechnol., 2006, 1, P.245. 4. D.V. Kalinin, V.V. Serdobintseva, V.F. Shabanov, Doklady Physics, 2008. V. 53. 4. P.192.

174

LASING IN PHOTONIC CRYSTAL OPAL FILMS AND HETEROSTRUCTURES

A.I. Plekhanov, A.S. Kuchyanov

Institute of Automation and Electrometry SB RAS, Novosibirsk, Russia

fractal@iae.nsk.su

One of the applied aspects of photonic crystals (PhC) is connected with the creation of effective light-emitting diodes and tiny laser sources. The effective light source is based on three-dimensional PhC with photonic band gap (PBG) and an active material with the emitting band which is coincident with the PBG. A potentially simpler and cheaper approach for creating three-dimensional periodic structures is the natural assembly of colloidal microspheres. One of such nanoscale regular structure is artificial opal. The opal structure opens wide prospects for composites with liquid crystals, laser dyes, etc. But artificial volume opals have usually irregular, polycrystalline structure. The single-crystalline PhCs that have defect densities sufficiently low then the artificial opals can obtain by assembling a thin layer of colloidal spheres on a glass substrate. To date, the lasing in artificial volume opal and in single-crystal opal film were observed [1,2]. We have studied the lasing in volume artificial opal, single-crystal opal films and opal heterostructures doped with Rhodamine 6G and excited by picosecond pulses of a second harmonic from a Nd:YAG laser. The artificial opals were prepared from crystallizing colloidal suspension of highly monodispersed spherical silica particles (MSSP) with the diameter ranging from 190 to 250 nm. The single-crystal opal films were prepared from a suspension of MSSP in a dynamic meniscus area [3]. The lasing threshold for Rhodamine 6G in the volume opal was found to be equal to 13 MW/cm2. The random lasing in artificial opals always peaks at the maximum of dye luminescence band. The generated peak is independent of the PBG. We have shown that monochromatic and directed laser emission can be obtained from dye-infiltrated single-crystal opal films. This lasing caused by Bragg diffraction inside of PhC, i.e. associated with the periodicity structure of the opal film. In this case the lasing always peaks at the boundary of the PBG. The excitation intensity threshold was about 2.5 MW/cm2. We have obtained also the lasing in three-layered heterostructure. It was found the outer PhC layers of this heterostructure serve as two-mirror cavity. This reduced the threshold by 3 times as compared with one-layer single-crystal film. This study was supported by the integration project of the SB of the RAS No.17 and by the Division of Physical Sciences, the RAS (program No. 8). 1. Frolov S.V., Vardeny Z.V., Zakhidov A.A., Baughman R.H. // Opt. Communs., 1999, v.162,

p.241. 2. Nishijima Y., Ueno K., Juodkazis S., Mizeikis V., et.al. // Optics Express, 2008, V. 16, No.

18, p.13676. 3. Plekhanov A.I., Kalinin D.V., Serdobinsteva V.V. // Nanotechnologies in Russia, 2006, v.1,

No.1,2, p. 245.

175

POLARIZATION AND ORIENTATION ANISOTROPY OF RESONANT OPTICAL PROPERTIES IN POLYMER 3D PHOTONIC CRYSTALS

A.V. Selkin1, V.G. Fedotov1, T.A. Ukleev1,

A.Yu. Menshikova2, N.N. Shevchenko2

1 – A.F. Ioffe Physical-Technical Institute RAS, St.Petersburg, Russia 2 - Institute of Macromolecular Compounds RAS, St.Petersburg, Russia

alexander.selkin@mail.ioffe.ru

Interaction of electromagnetic field with spatially-periodic solid-state structures which permittivity changes with spacing comparable with wavelength of light is accompanied by a number of striking diffractive optical phenomena that can be assigned to strong modification of the eigenmode energy spectrum. These structures, the called photonic crystals (PhC), have been attracting intense interest that can be traced to the possibility of efficient control of light propagation within PhC and to currently emerging applications in laser technology and optoelectronics. On the other hand, such structures are novel nontrivial objects that can be used to advantage in exploring fundamental aspects of nanophotonics. We report here on experimental and theoretical studies of the mechanisms accounting for the spectra of resonant Bragg diffraction from polymer PhCs with the opal fcc crystal lattice. We used for model experimental objects the polymer PhC films made up of monodisperse polystyrene particles. Attention is focused primarily on an investigation of novel optical effects associated with polarization and orientation anisotropy of PhC possessing high dielectric contrast. Such kind of anisotropy is shown to be a specific property of three-dimensional (3D) PhC, which looks unusually in terms of traditional crystal optics. A special feature in interaction of light with 3D PhC is due to the following factors: (i) the fulfillment of the condition when resonant Bragg diffraction occurs simultaneously on the crystal planes non-parallel to each other, (ii) the specific spectrum of electromagnetic PhC eigenmodes with an account of surfaces and interfaces and (iii) the polarization properties of the eigenmodes for which, in general, fails usual TE-TM classification with respect to the polarization state. An analysis of experimental data was carried out within the framework of the approach [1] suggested earlier. A good agreement between the results of theory and experiment is demonstrated thus being evidence in favour of the generalized Ewald-Oseen extinction principle as applied to the 3D PhC structures whose spatial period is comparable with the wavelength of light [2]. We call attention here to the existence of the regions in the energy spectrum of PhC where more then one eigenmode can be excited at the same frequency. This kind of multimode regime of light propagation inside the PhC means that additional boundary conditions for the field amplitudes are required as it is done for instance in crystal optics with spatial dispersion of dielectric function [3]. 1. A.G. Bazhenova, A.V. Sel’kin, A.Yu. Men’shikova, and N.N. Shevchenko. Physics of the

Solid State, 49, No.11, pp. 2109-2120 (2007). 2. P.A. Belov, C.R. Simovski. Phys. Rev. B 73, 045102 (2006). 3. V. Agranovich and V. Ginzburg. Spatial Dispersion in Crystal Optics and the Theory of

Excitons (Wiley-Interscience. New York, 1966).

176

NANOPHOTONICS OF FULLERENE SOLUTIONS

E.F. Sheka1, B.S. Razbirin2

1 - Peoples’ Friendship University of Russia, Moscow, Russia 2 - A.F. Ioffe Physical-Technical Institute RAS, St.Petersburg, Russia

b.razbirin@mail.ioffe.ru

Nanophotonics of fullerenes is mainly associated with the impact of low doping of fullerenes on characteristics of nonlinear optical (NLO) media and, as a result, of NLO devices. Obvious electromagnetic nature of NLO effects enhancement and a direct influence of electric field on the enhancement witness convincingly the recruitment of charge states in the considered features. These states have been explained by the formation of charge transfer complexes due to donor-acceptor (DA) interaction between fullerenes and host matrices. The paper concerns the origin, structure, and spatial extension of the complexes. Empirically, the complexes are studied via enhancement effects which follow Raman scattering and one-photon luminescence of fullerene-doped matrices. Computationally, the DA interaction is considered through its influence on the total intermolecular interaction between solute (fullerene) molecules (sol-sol interaction) as well as between solute and solvent molecules (sol-solv interaction). Empirical features are exhibited by an additional blue emission spectrum in diluted fullerene-doped matrices which appears under excitation in the visible and near UV regions subjected to resonance conditions [1-3]. The blue spectrum presents a combination of enhanced Raman scattering and enhanced one-photon luminescence of both solvent and fullerene molecules, the latter involved in clusters, and is attributed to the enhancement of linear optical effects caused by the formation of sol-sol and sol-solv clusters. A particular contribution of these spectral components into the blue emission of a certain solution depends on chemical structure of the fullerene. Quantum-chemical computations performed in the study permitted to evaluate the strength of the intermolecular interaction in the clusters and highlight their charge-transfer origin. The observed enhancement of linear optical events is considered within the framework of the enhancement local field model and is connected with the resonance excitation of the clusters which are spatially extended charge-transfer complexes. The excitation light is transformed into local charge-transfer excitons within the clusters providing the polarization of the medium enough for the enhancement of the local electric field of the incident and outgoing light. A direct connection is established of the intensity of the observed linear optical features with the efficacy of the media nonlinear behavior, at one hand, and with a coupling strength of the cluster formation, on the other. Empirical and computational probing is suggested that permits to test a fullerene-doped matrix for its applicability towards nonlinear optical applications. The work is financially supported by the RFBR (grant 07-03-00755). References

1. B.S. Razbirin, E.F. Sheka, A.N. Starukhin, D.K. Nelson, P.A. Troshin, R.N. Lyubovskaya, JETP Lett. 87, 133 (2008)

2. E.F. Sheka, B.S. Razbirin, A.N. Starukhin, D.K. Nelson, M.Yu. Degunov, L.N. Lyubovskaya, P.A. Troshin, JETP. 108, 738 (2009) [ZhETF 135, 848 (2009)].

3. E.F. Sheka, B.S. Razbirin, A.N. Starukhin, D.K. Nelson, M.Yu. Degunov, P.A. Troshin, R.N. Lyubovskaya J.Nanophot. SPIE 3, 033501 (2009)

177

NANOPHOTONICS IN PRINTING AND PACKAGING. DIGITAL AND ANALOGUES IMAGES TREATMENT AND PRODUCIN G

V. Sherstiuk, S. Molodid

National Technical University of Ukraine “Kiev Polytechnic Institute”

sherstyukv@ukr.net

The achievements and perspectives of nanosciences and nanotechnology determine the modern stage of scientific and technical progress. The trends are considered in microminiaturization in printing and some features of dispersed systems in nano sized scale as well as their applications in Graphic Arts and packaging. The trend toward ever-smaller semiconductors was first noticed as long ago as 1965 according the formulation now known as Moore's Law: The number of components that can fit on an integrated circuit (and quantity of information, correspondently) doubles every 18 months to two years. On the Moore’s diagram at beginning of 1980-es the minimum dimension of elements of electronic devices to the period of 2005-2010 must be less 0.1 µm or 100 nm. It means that elements in electronic and photonic devices must have sizes of nanometer dimension. The imprint lithography is now one of the perspective ways for producing micro- and nanosized devices. But there are problems of preparing photo masks by means of usual photography. That is why it is reasonable to look at the lithography and photolithography development and the problem of the images treatment in analogous and digital versions. There were compared images formation and transformation from digital to analogous and there and back. The modern imprinting lithography as a kind of nanotechnology is concerned in view of future security printing, producing RFID tags and other applications for packaging. Now there are actual synthesis and stabilization of nanoparticles and photoactive nanocomposites in polymer matrixes and on the surfaces for their utilization by micro- and nanocontact printing techniques. Dimensions of nanoparticles grow spontaneously usually. The problem of obtaining particles of certain size and geometry is rather important and actual. The nanocomposites stabilized will be perspective in different areas of printing nanotechnologies. Luminescent compositions may be rather attractive for printing and packaging. Improving of light emission (in photo, electric and magnetic fields) of dispersed compositions and filled polymer composites and nanocomposites is dealt with understanding of the influence of size of particles, value of surface, formation of electron acceptor and electron donor centers on the surface. The aggregation of dispersed particles during transformation of ink-varnish nanocompositions into fixed prints changes the luminescence parameters. Properties of photo emitting nanocomposites depend upon the nature and parameters of surroundings. Thus, the fundamental tasks for investigation of influence of these factors upon the efficiency of luminescence and stabilization of the nanocomposites properties are to be considered and studied. Special ink systems were designed for the identification of authenticity of printed matter by the luminescent and magnetic properties of inked impressions. There was discovered that paramagnetic properties of magnetite particles with luminofor molecules changed at UV light illumination. It was found that the introduction of luminescent substances into general-purpose printing inks causes luminescence quenching by printing-ink curing catalysts. Magnetite particles coated with luminescent substances exhibit changes in the magnetic (in particular, paramagnetic) properties depending on the luminescent molecules nature and the surface pre-treatment procedure The study was carried out at the financial support of the State Foundation of Fundamental Researches, Ministry of Education and Science of Ukraine (the project No.F25.4/052).

178

PHOTOPHYSICAL AND PHOTOCHEMICAL EFFECTS IN ASSEMBLIES OF NANOPARTICLES IMMOBILIZED ON METAL OR DIELECTRIC SUBSTRATES AND MOLECULAR TEMPLATES

N.D. Strekal, S.A. Maskevich

Yanka Kupala Grodno State University, Grodno, Belarus nat@grsu.by

Semiconductor nanoparticles with CdSe emissive core and passivative ZnS shell (CdSe/ZnS NPs) are well known fluorophores with a number of advantages over organic fluorophores. The electronic spectra of NPs are size-dependent due to quantum confinement effects and the term Quantum dots (QDs) is widely used for designation them in the line of other systems of low dimensionality. They posses of a wide (from UV to red range in dependence of its size) absorption band, narrow (ca 30 nm) photoluminescent (PL) band and narrow (ca 5 nm) Stocks shift between the long-wave edge of absorption and PL bands. The overlapping of NPs excitation profiles enable NPs with different emission wavelengths to be simultaneously excited. That advantage is very important in multiplex application1. The use of broadband excitation source posses also the extremely high brightness and photostability. The nanocrystalline nature of these objects display superior chemical (dispersible in different solvents), photochemical and photophysical properties. There are many applications that have been proposed for CdSe/ZnS NPs: optoelectronics, tunable lasers and LEDs, photonics, biosencing and bioimaging etc. The aim of our work is the engineering of self-assembled NP superlattices of different level (1D or 2D) with presumably collective properties. With this aim we use the different capping agents to redisperse the NPs in aqueous solution and self-assembled immobilization on the plane dielectric, plasmonic gold surface or molecular templates. We have obtained self-aggregated patterns of CdSe/ZnS NPs (3,2 nm in diameter, Birch Yellow, www.evidenttech.com) on different substrates. On the surface of chemically modified glass (Silan prep, Sigma) these patterns present the rings and globules of different sizes and shapes. It was revealed that big (in comparison to light wavelength) and initially bright aggregates develop the bleaching with time under continuous illumination. The same illumination causes the increase of PL intensity for little NP globules and rings up to two orders of magnitude. Emission from the samples with photoactivated properties becames polarized when PL signal reached the saturation. The degree of polarization grows up to 20-30% if excitation laser light has s – poliarization. Also mean PL decay time strongly decreases as result of photoactivation from tens of nanoseconds (for NPs in aqueous solution) to picosecond range for NP photoactivated aggregates on glass slides. PL properties of these QDs ensembles strongly depend on excitation conditions. The set of observed data shows that the PL enhancement may not be only accompanied by QD surface rearrangement and photooxidation (chemical effects of light) but also may be caused by some optical alignment of QD excitons by plane-polarized light (electro-magnetic effects). Some alignment of excitons is recently presented in 2. The bright and stable fluorescent nanowires were obtained by molecular combing of cationic polyelectrolites (PE) complexes with mercaptoacetic acid capped CdSe/ZnS NPs (anionic NPs). It was determined that NPs size as well as PE:NPs stoichiometric molar ratio are the crucial parameters, which define the topology of NPsPE complexes stretched on solid substrate. The conditions for formation nanowire complexes based on NP-labeled PAA also were found. The spectral overlap of plasmon excitation band and NP emission band as key factors influencing on PL enhancement under immobilization on gold plasmonic films is also discussed.

1 R. L Ornberg, T. F. Harper, H. Liu. // Nature Methods 2, 79 - 81 (2005). 2 Gaponenko S.V. at al. Optics of nanostructures. (Russ) Ed. by Fedorov A.V. St-Petersburg, Russia. Nedra, 2005, 326 p.

179

SEMICONDUCTOR PHOTOCATALYSIS ON THE NANOSCALE: STATE-OF-THE-ART AND PERSPECTIVES

A.L. Stroyuk, S.Ya. Kuchmiy, A.I. Kryukov, V.D. Pokhodenko

L.V. Pysarzhevsky Institute of Physical Chemistry NAS, Kyiv, Ukraine

stroyuk@inphyschem-nas.kiev.ua

A background and principles of semiconductor nanophotocatalysis – a new trend in photochemistry dealing with the photocatalytic redox-reactions with the participation of semiconductor nanoparticles – is discussed. The origins of various size-dependent phenomena in the semiconductor photocatalysis are highlighted with the special attention paid to the quantum size effects originating from a spatial confinement of the photogenerated charge carriers (excitons) in ultra-small semiconductor nanoparticles (quantum dots). The specifics of quantum-confined semiconductor nanoparticles is discussed, including the size-dependent optical properties (the position and shape of absorption and photoluminescence bands, the oscillator strength of interband electron transitions, etc.), thermodynamic characteristics (the band gap, the potentials of conduction and valence band edges, the nature, number and depth of charge trapping sites, etc.), as well as the dynamics of photogenerated charge carriers (charge migration in semiconductor nanoparticles, its localization on the structure defects, interfacial charge transfer, etc.). The most important consequences of spatial exciton confinement in semiconductor nanoparticles affecting their photocatalytic behavior are discussed. Particular attention is paid to the development of the photocatalytic properties in narrow-band-gap semiconductors at the nanoscale, the increase of a number of photocatalytic reactions for a given nanocrystalline semiconductor as compared with the bulk material, and the acceleration of photocatalytic reactions with the participation of semiconductor nanoparticles due to size-dependent growth of the energy of charge carriers. The photoinduced polarization caused by the accumulation of excessive charge by semiconductor nanoparticles and resulting in a remarkable increase of their photocatalytic activity is discussed. The specific features of the photocatalytic behavior of semiconductor nanoparticles are illustrated in the chapter by a number of examples. In particular, the size-related phenomena in the photocatalytic metal reduction, photocatalytic formation of binary semiconductor nanoheterostructures, photoinduced polymerization of acrylic monomers, photocatalytic reduction of sulfur compounds, and photocatalytic water reduction with the participation of semiconductor nanoparticles are discussed. Special attention is paid to the photochemical behavior of quantum-confined semiconductor nanoparticles under powerful pulse illumination. The examples of simultaneous and additive influence of different size effects upon the photocatalytic properties of semiconductor nanoparticles are demonstrated. In conclusion, perspectives of future development of the photocatalytic systems based on nanostructured semiconductors are given, outlining the ways for their further perfection, broadening of the number of known nanophotocatalysts and photocatalytic processes, as well as the benefits of the utilization of such systems in modern nanotechnologies.

180

COFLUORESCENCE OF DYES IN NANOSTRUCTURES OF METAL ION COMPLEXES WITH DIKETONES

E.B. Sveshnikova, V.L. Ermolaev, S.S. Dudar

St.Petersburg State University of Information Technologies, Mechanics and Optics, Russia

ermolaev@oi.ifmo.ru

The phenomenon of Ln3+ luminescence enhancement in structures of their complexes was given the title of columinescence. Beginning from nineties of last century this phenomenon has a wide use in chemical and immuno-luminescent analysis. We have shown for the first time that columinescence intensity of Ln3+ complex nanostructures (NS) in aqueous solutions is determined not only by migration of ligand triplet energy of complexes forming NS, to complexes of Eu3+, Tb3+ or other luminescent ions; but also by the increase of luminescence yield of these complexes under their incorporation into NS. It is found by us that the sensitized fluorescence (cofluorescence) of dye molecules occurs under their incorporation in NS of diketonate complexes of metal ions in aqueous solutions. We revealed [1] that in aqueous solutions of β-diketones (0.1–30 µm), Eu3+, Gd3+, Al3+, Sc3+, In3+

(0.1–30 µm) and dye molecules (1–1000 nm) NS of ion complexes with dye admixture are formed. Irradiation of such NS into the ligand absorption band leads to dye cofluorescence appearance if the excited singlet levels of dyes are situated below than the analogous ones of diketone. The cofluorescence intensity is shown to depend on NS size and morphology, choice of ions of complexes, forming NS and quantum yield of dye fluorescence in NS. Dye cofluorescence is examined in NS of four diketonate and hydroxy-diketonate complexes of ions with cationic forms of dyes: nile blue, malachite green, rhodamine 6G and B, cryptocyanine and other ones. There are two processes of dye sensitization in NS of Eu complexes with admixture of dyes having S1 level below than 5D0 level of Eu3+: S–S energy transfer from ligands to dyes which leads to dye cofluorescence with ns lifetimes, and energy transfer from Eu3+ to dye that is responsible for delayed dye cofluorescence with 1–50 µs times. It is shown that at dye concentration in solution less than 100 nM the delayed cofluorescence dominates in the integrated sensitized dye fluorescence. At higher dye concentrations the intensity of usual and delayed cofluorescence are commensurable and concentration quenching of dye fluorescence is observed. S–S energy transfer to dyes is observed even in those NS where complex fluorescence is not detected. The discovery of dye cofluorescence in NS allows to expand a set of different spectral luminescent labels in analyses, including time-resolved immuno-analysis and allows also to enhance the sensitivity of luminescence method of analysis, using dye molecules as labels. 1. Dudar S.S., Sveshnikova E.B., Ermolaev V.L. Optics and Spectroscopy, 2008, V.104, No 2,

pp. 225–234; No 5, pp. 724–731; 2009, V.107, No 1 (in press).

181

NANOSIZE STRUCTURES IN POLYMER BASED SOLAR CELLS

A.R. Tameev, A.V. Vannikov

A.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia tameev@elchem.ac.ru

Nanosize structures (nanoclusters, NCs, and nanoparticles, NPs) of organic and inorganic materials are of interest for studies of photo-physics and applications in organic solar cells. Among polymer materials, bulk heterojunction solar cells based on polyphenylenevinylene derivatives (MEH-PPV, MDMO-PPV) or polythiophene derivative (P3HT) and fullerene derivative (PCBM) yield the most power conversion efficiency (~ 5%) [1-3]. The nanosize structures are formed in a polymer composite even in the course of thin layer casting from solution. We have demonstrated the formation of ordered molecules NCs in thin layers of MEH-PPV and NCs influence on charge carrier transport behaviors and mobility and photovoltaic characteristics [4,5]. PCBM molecules (electron acceptors as well as quenchers of polymer luminescence), form NCs in the process of preparation of the polymer composition. The PCBM NCs define the morphology of the polymer layers and therefore photovoltaic parameters of the cells [6]. Nanosize crystals of J-aggregated cyanine dyes embedded in a polymer composition provide reasonable high mobility of charge carriers [7] resulting in increased photovoltaic current in solar cell [8]. The charge transport behaviors in polymer composites doped with the cyanine dye J-aggregates and single-walled carbon nanotubes (SWNTs) are similar [7,9]. SWNTs are also used in the development of organic solar cells. Photophysical properties of metal NCs and NPs are of particular interest for utilization in organic solar cells [10]. Au and Ag NCs (NPs) introduced between an electrode and photoactive polymer layer were found to increase photovoltaic current a several times [11]. The enhancement of the photovoltage is due to incident light which excites a surface plasmon on the metal NP. In this process, the NP (NC) can then (1) re-radiate most of its energy into the polymer in such a way that the light is trapped inside the cell, (2) transfer its energy to a single electron within the metal NP, emitting the electron [12]. The interaction between light and metal NPs also leads to increases in the electromagnetic field around the particles. This will increase the light absorbed by the organic (polymer) molecules in that region and consequently the number of charge carriers [10]. In the report, experimental results and discussion of the mentioned above problems are presented. The work was supported by the RFBR (08-03-00796, 07-03-00149) and ISTC (3718) projects. References 1. H. Hoppe and N.S. Sariciftci, J.Mater. Chem. 16 (2006) 45. 2. B.C. Thompson and J.M.J. Frechet, Angew. Chem. Int. Ed. 47 (2008) 58. 3. P.A. Troshin, R.N. Lyubovskaya, V.F. Razumov, Nanotechnol. in Russia. 3(5-6) (2008) 242. 4. A. R. Tameev, S. V. Novikov, A.V. Vannikov et al., Proc. IEEE 4th World Conf. Photovoltaic Energy

Conversion, 2006. V.1. P.244–246. 5. Y-F Huang, A.R. Inigo, C-C Chang et al., Adv. Funct. Mater. 17 (2007) 2902. 6. D. Chirvase, J. Parisi, J.C. Hummelen and V Dyakonov, Nanotechnology 15 (2004) 1317. 7. A. R. Tameev, S. V. Novikov, A.V. Vannikov. Ross. Nanotechnol. 2(11-12) (2007) 97 (in Rus). 8. A.R. Tameev, A.V. Vannikov, and H.F.M. Schoo, Thin Solid Films 451-452 (2004) 109. 9. A.R. Tameev, L.Ya. Pereshivko, A.V. Vannikov. Mol. Cryst. Liq. Cryst. 497 (2008) 333. 10. B.P. Rand, P. Peumans, S.R. Forrest, J. Appl. Phys. 96 (2004) 7519. 11. V.A. Kolesnikov, A.R. Tameev, S.V. Novikov et al. Proc. 19th Eur. Photovoltaic Solar Energy Conf., 2004.

P.363-366. 12. M.Westphalen, U. Kreibig, J. Rostalski et al., Sol. Energy Sol. Cells 61 (2000) 97.

182

SPATIAL DISPERSION AND LOCAL FIELD EFFECTS FOR SEMI-INFINITE MEDIA WITH EMBEDDED NANOPARTICLES

A.A. Tishchenko, M.I. Ryazanov, M.N. Strikhanov

MEPhI, Moscow, Russia tishchenko@mephi.ru

The well known fact is that the average field acting on a molecule differs from the macroscopic field. The usual way is to call the field obtained by averaging the solution to the microscopic Maxwell equations over the quantum states of atomic electrons and the thermal motion of nuclei – to call it by macroscopic field [1], and to call average field acting on a single molecule by local field. The effects resulting from the difference between the local and macroscopic fields are called local field effects. Relations between the external field, the macroscopic field and the local field lead to the Clausius–Mossotti formula; for three-dimensional systems this can be obtained by using a pair distribution function for molecules [2]. In this paper the Clausius-Mossotti relation have been obtained for half-infinite medium with the monolayer of other particles on its surface. The interaction between a molecule and an electromagnetic field is analyzed in the dipole approximation, which is good approximation at wavelengths much longer than the intermolecular distance. For the three limits the results couincide with ones obtained before: i) the case of infinite medium give us the standard, well-known Clausius-Mossotti relation [3]; ii) the case of half-infinite medium without surface monolayer. Here Clausius-Mossotti relation is obtained with corrections due to limitation in one direction. The divergence is considerable near the surface and vanishes far from it [4]; iii) the case of a monolayer only, without the substrate - this limit gives the expressions obtained in Ref. [5]. It should be mentioned that in this work the relations between the local and macroscopic field are only treating; to find a relation between the local field and a field of external sources in 3D case is more difficult problem, and it is not dealt with here. The effects of spatial dispersions are considered. Also, the possible applications of the theory developed are discussed. References

1. V.L. Ginzburg, Application of Electrodynamics in Theoretical Physics and Astrophysics. (Gordon and Breach, 1989).

2. O.V. Dolgov and E. G. Maksimov, Usp. Fiz. Nauk 135 (1981) 441. 3. M.I. Ryazanov, Electrodynamics of Condensed Matter (Nauka, Moscow, 1984) [in

Russian]. 4. M.I. Ryazanov, JETP 83 (1996) 529 [ZhETF 110 (1996) 959]. 5. M.I. Ryazanov and A.A. Tishchenko, JETP 103 (2006) 539 [ZhETF 130 (2006) 621].

183

ORDERED STRUCTURES ON THE BASIS OF SELF-ASSEMBLY OF CdSe AND Au PARTICLES

M.A. Zaporohzets1, V.I. Nikolaichik2, V.V. Volkov1,

D.A. Baranov3, К.А. Dembo1, S.N. Syl’yanov1, O.M. Zhigalina1, S.P. Gubin3, A.S. Avilov1, I.I. Khodos2

1 – A.V. Shubnikov Institute of Crystallography RAS, Moscow, Russia

2 - Institute of Problems of Microelectronics Technology RAS, Chernogolovka, Russia 3 - N.S. Kurnakov Institute of Gen & Inorg Chemistry RAS, Moscow, Russia

zaporozhets_m.a@mail.ru

Preparation of monodisperse nanoparticles of different materials is one of the important current problems of nanotechnology development. Apart from the fact that nanoparticles themselves have the unique set of physical properties, size uniformity of nanoparticles provides a potential possibility to form diverse structures from them. An effective mechanism of structure formation is self-assembly of particles into so called “superlattices”, where similar to atoms in classical crystals, nanoparticles are ordered in a strictly definite manner. In order for that to be realized, development of effective methods of nanoparticles synthesis providing a narrow size distribution and maximum form similarity is needed. It is expected that ordered structures made of nanoparticles will display new properties different from the properties of isolated nanoparticles. Preparation techniques of two types of nanoparticles - cadmium selenide and gold - have been developed, and ordered structures on their basis have been prepared in this study. CdSe nanoparticles were synthesized by interaction of cadmium stearate with triphenylphosphine in heptadecan mediumin at the presence of oleamin and triphenylphosphine oxide as surface active agents (SAA). Au nanoparticles were prepared by reduction of HAuCl4 in hexane through boron hydride at the presence of SAA. The analysis of X-ray and electron diffraction patterns have revealed that samples of CdSe and Au nanoparticles are single phased. CdSe nanoparticles have a wurzite structure (the P63mc space group). Crystal structure of Au nanoparticles is described in terms of face centered cubic lattice (the Fm3m space group). It is found by techniques of high resolution electron microscopy and X-ray small angle scattering that prepared samples contained nanoparticles of spherical form with a narrow size distribution. An average size of CdSe nanoparticles was 12 nm, and that of Au nanoparticles was 10 nm. Nanoparticles form observed in a transmission electron microscope did not change at sample tilting that supports its spherical character. Self- assembly of nanoparticles into close-packed 2D ensembles having the 6-order symmetry axis was observed in regions with high deposition density of CdSe nanoparticles onto carbon substrate. The pronounced texture was present in CdSe ensembles such that all nanoparticles were orientated with the [001] direction perpendicular to carbon film surface deposited with nanoparticles. A new type of ordered CdSe ensembles formed of particles with fine-domain structure has been found. No texture in the form of either preferred orientation of nanoparticles crystal structure in relation to each other or to the substrate has been found in 2D close packed ensembles of Au nanoparticles. The 3D structures of Au nanoparticles have been found where the second layer of nanoparticles resides in voids of the first layer forming a close-packed bulk ordering of nanoparticles in that manner.

184

OPTICAL PROPERTIES OF NANO-STRUCTURED POLYMER LIQUID CRYSTAL COMPOSITES

G.M. Zharkova, A.P. Petrov, V.M. Khachaturyan

S.A. Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia

Zharkova@itam.nsc.ru

Now the production of new high-structured functional materials on the base of polymer-liquid crystals composites is studied intensively. The holographic method, based on the photo-polymerizing composition emitted with the light of an interferential pattern, permits to form the composites with the periodic structural formations of nano-size range [1].The presence of the developed surface of the supramolecular structures of such composites, on which boundary the initial orientation of the liquid crystal (LC) forms, as well as this surface periodicity change the optical properties of the composite. The formed composites show diffraction properties, and their optical properties can be tunable. The influence of the supramolecular formations geometry of the polymer liquid crystal composite on the orientation distribution of molecules in a small volume has been analyzed theoretically. It has been revealed that the LC molecule orientation is affected by the orienting effect of the volume geometry and the ratio of the liquid crystal elasticity factors (splay and bend) К1/К3. Under analysis are the evolution of the NLC optical properties regarding the type and characteristic sizes of the supramolecular structure of the composites formed by the photopolymerization method. The composites formed at the pre-polymer light exposition with the uniform and non-uniform intensity distribution (the holographic method) have been studied experimentally. In the first case, polymer-disperse liquid crystals are formed (a). In the second case, this is a structure consisting of alternating bands enriched either with the polymer or with the LC (b) [2].

a) b)

The optical properties of the composites have been compared subject to the formed structure; the peculiarities of the light diffraction on the photopolymer liquid-crystal composites, caused by the nano-size structural formations, have been analyzed. 1. Sutherland R.L., Natarajan L.V., Tondiglia V.P., Bunning T.J. Bragg gratings in an acrylate

polymer consisting of periodic polymer-dispersed liquid-crystal planes // Chem. Mater. 1993. V. 5. pp. 1533-1538.

2. Zharkova G.M, Petrov A.P, Samsonova I.V.and Khachaturyan I.V. Investigation of the optical properties of polymer-liquid crystal holographic materials for use in photonics// High Energy Chemistry.2008.Т.42. 7.pp.546-547.

185

POSTERS

DIFFERENTIAL PARAMETERS OF ORGANIC PHOTOELEMENT WITH BULK HETEROJUNCTION

S.D. Babenko1, Yu.L. Moskvin1, P.A. Troshin2, A.A. Balakai1

1 - Branch of Institute of Energy Problems of Chemical Physics RAS, Chernogolovka, Russia

2 - Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia balakai@binep.ac.ru

Organic bulk-heterojunction solar cells have attracted considerable attention as a promising approach to future photovoltaic energy sources. Improvements in performance are depend on developing a better understanding of the pertinent processes such as charge separation, geminate recombination, shunts, and leakage. The pulse laser method of probing has been employed to determine differential parameters of such cell. The values have been estimated from the transient photopotential with different loading resistances. Serial and shunt internal resistances, capacity, and relative charge separation efficiency have been measured over voltage range (-1400 mV ÷ 600 mV). The received values of resistances and separation efficiency show an agreement with once deduced from J-V characteristics in dark and under pulse illumination. It has been revealed 6-fold growth of measured capacity at direct applied voltage (fig.1.)

Fig.1. Differential capacity (Cdif) as a function of applied voltage. Cg is cell geometric capacity. We propose that generated charges partly exist at electrodes and in active layer as electron-hole pairs and the fast charge exchange take place between pairs and electrodes. The fraction of the bound charges in pairs increases and average distance between positive and negative charges decreases markedly at direct voltage. This causes the observed growth of capacity.

186

A COMPARISON OF THE PHOTOPHYSICAL PROPERTIES OF CADMIUM CHALCOGENIDE NANOPARTICLES

SYNTHESIZED BY VARIOUS METHODS

V.Yu. Gak1, D.Yu. Nikolenko1, S.B. Brichkin1, V.F. Razumov1, M.A. Zaporozhets2

1 - Institute of Problems of Chemical Physics RAS

2 - Institute of Microelectronics Technology and High-Purity Materials RAS gak@icp.ac.ru

Various application areas of luminescent probes such as fluorescent tomography, requires to develop a contrast luminescent labels. One of the most perspective objects for this aim are AIIBVI semiconductor nanoparticles (NPs). The main methods of obtaining of monodisperse semiconductor NPs of specified size with both spherical and anisotropic shape are high-temperature colloidal synthesis and synthesis in the reverse micelle (RM) solutions. RMs act here as nanoreactors with controllable size and shape. Cadmium chalcogenide (CdX, X=Se, S) NP of various size and shape were synthesized in the sodium bis(2-ethyl-hexyl)sulfosuccinate (AOT) RM solutions, using cadmium nitrate, sodium sulfide and pre-synthesized sodium selenosulfate (Na2SeSO3) water solutions as precursors and n-heptane as a dispersion medium. The characteristic size of NPs was controlled by varying w0=[H2O]/[AOT] value, defining RM water pool diameter. For further research NPs were passivated by dodecanethiol. Aspherical CdS nanoparticles are synthesized in RM solution under ultrasound treatment during all the time of its formation. The essence of essence of the method consists in the reorganization of RMs under ultrasound irradiation and the subsequent aggregation of the NPs into rod-like structures. CdX NPs were also obtained by the method of high-temperature colloidal synthesis under conditions of ‘‘size distribution focusing’’ due to controlled decrease of temperature, by injection of trioctylphosphine-chalcogene complex into trioctylphosphine oxide (TOPO), hexadecylamine, stearic acid or their mixture. In order to synthesize anisotropic NPs of CdSe at first a synthesis of sphalerite structure nanoparicles in stearic acid was performed. Then these NPs were transferred into TOPO/stearic acid mixture where wurtzite structure CdSe is formed in such conditions. As a result of this synthesis the tetrapod-shaped CdSe NPs have been obtained. In the present work a comparative study of CdX NPs, received by these two methods, has been performed by the methods of transmission electron microscopy (TEM), steady-state absorption and luminescent spectroscopy, and time-resolved laser fluorescent spectroscopy. The luminescence decay curves of CdX NPs are non-monoexponential and the best fit may be obtained with three-exponential law. On the basis of the obtained spectral and kinetic data of nanorods it is possible to draw a conclusion about mechanism of luminescence of CdS NPs synthesized by these method. In reverse micelle synthesized In the particles synthesized in reverse micelles it has a trap mechanism, while for the NPs obtained by the method of high-temperature colloidal synthesis prevails aa band-gap one. Changes in the absorption, luminescence and excitation spectra of samples received under the influence of ultrasound, can serve as signs of formation of nanorods. This work is financially supported by Program of Fundamental Research RAS No. 27 “Basic fundamental research in nanotechnology and nanomaterials”, and Russian Foundation for Basic Research (project 07-03-00397).

187

INVESTIGATION ON THE POSSIBILITY OF COVERING CYANINE DYE J-AGGREGATES WITH SILICA SHELLS

A.V. Ivanchikhina

Moscow Institute of Physics and Technology

and Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia Ivanchihina@gmail.com

J-aggregates have attracted the interest of several research groups, due to their peculiar spectral properties which make them potential candidates for applications in biology, as e. g. fluorescent labels. The preparation of monodispersed nanometer-sized J-aggregates is of great practical importance for this purpose. One of possible ways of solving this problem seems to be the use of reverse micelles. Moreover, an additional stabilization of J-aggregates is necessary to isolate them from micellar solutions. Protecting J-aggregates by silica shells is suggested. Reverse micelles based on polyoxyethylene (5) nonylphenyl ether (NP-5) are known to be used for capsulation of different nanoparticles and dye molecules in silica. However there is no literature data on preparation of J-aggregates in NP5 reverse micelles. We have studied (for the first time) the behavior of J-aggregates of a cyanine dye, 3,3’-di-(γ-sulfopropyl)-4,5,4’,5’-dibenzo-9-ethylthiacarbocyanine betaine pyridinium salt, in NP5/water/ cyclohexane reverse micelles within the range of W (W=[H2O]/[NP5]) from 3.1 to 8.3. Since there is no any exact dependence of RM size on W for NP5, so hydrodynamic radii have been measured by DLS for W = 3.1 ÷ 8.3. We have worked out the method of dye micellar solution preparation that gives reproducible results and permits to get maximum J-aggregates of minimal sizes. As-prepared RM solutions contain the dye mainly in the J-aggregate form with a small amount of trans-monomers in the whole range of W. Further evolution of absorption spectra is markedly different for different W. For micellar solutions with W = 3.1 ÷ 4.0 there is a dye transition from J-aggregate form to trans-monomer one and precipitation of J-aggregates located in cyclohexane during the whole observation period (24 h). For W = 4.2 ÷ 8.3 the intensity of J-band increases during about 3 minutes and then decreases owing to the precipitation of J-aggregates located not in the water pool. Moreover, for the whole range of W the higher the W (the smaller concentration of NP5 molecules and the larger RM sizes), the lesser amount of precipitated aggregates. Taking into account that the largest amount of J-aggregates is in RM water pools at W=6,3, it was just the value of W that was used for preparation of silica nanoparticles. A mean particle diameter is 30 nm, standard deviation is 1 nm. As ammonia was used as catalyst for praparation of SiO2 nanoparticles, its influence on J-aggregates behavior in RMs and properties of final SiO2

particles has been studied. The intensity of the J-band it was shown to decrease twice after a 24-h when 2% aqua ammonia solution used as dispersed phase. The obtained data show NP5/water/cyclohexane to be suitable for capsulation of dye J-aggregates by silica shells. This work is financially supported by Program of Fundamental Research RAS 27 “Basic fundamental research in nanotechnology and nanomaterials”.

188

THE LUMINESCENCE OF POLYMER COMPOSITE MATERIALS WITH CdS NANOPARTICLES

V.I. Kochubey, Ju.G. Konyukhova, I.V. Zabenkov

Saratov State University, Russia

kochubey@optics.sgu.ru

The structure and the optical characteristics of CdS nanoparticles synthesized in high-pressure polyethylene were examined. The synthesis was carried out by means of high-temperature decomposition of precursors in the melt of polyethylene under argon atmosphere. The structure of the nanoparticles was investigated by RFA and EXAFS methods. It is shown that the particles have a greenockite-type hexagonal structure. The presence of cubic phase in the small concentration is also possibly. From the EXAFS spectra obtained at room temperature, it was drawn a conclusion that the disordereding degree of the cadmium ion environment decreases in the nanoparticles in comparison with the macroobjects. In view of the strong light scattering in the specimens the calculation of coefficients of absorption and scattering by the method of inverse adding-doubling was carried out. The films with a thickness of 60-150 µm were formed, and spectral measurements of complete transmission, diffuse reflection and collimated transmission were conducted. It follows from the obtained data that the position of the edge of absorption in the specimens weakly depends on average size of nanoparticles. This can be explained by the significant polydispersion of the nanoparticles. It is shown that the luminescence spectra of the specimens are distorted strongly as a result of scattering and self-absorption of luminescence inside the specimen. To correct the experimental spectra, the simulation program by the Monte Carlo method of the process of the propagation of luminescence in a specimen was constructed. It is shown that in the corrected spectra the shift of the maximum of the luminescence band into the short-wave spectrum region occurs. In this case the dependence of the maximum position on the precursors used and on the temperature of synthesis was discovered. The work partially supported by RFBR Grants 08-02-00404-а and 09-03-00369-а.

189

PHOTOELECTRIC NONLINEAR OPTICAL AND PHOTOREFRACTIVE PROPERTIES OF COMPOSITES FROM POLYVINYLCARBAZOLE AN D

SINGLE-WALLED CARBON NANOTUBES

T.V. Krivenko1, L.Ya. Pereshivko1, A.D. Grishina1, V.V. Savelyev1, R.W. Rychwalski2, A.V. Vannikov1

1 - A.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia

2 - Department of Materials Science and Engineering, Chalmers University of Technology, Göteborg, Sweden

van@elchem.ac.ru

The nonlinear optical properties, photoelectric and photorefractive (PR) sensitivities at 1064 and 1550 nm in the polymer composites from polyvinylcarbazole (PVK) doped with unoxidized and oxidized single-walled carbon nanotubes (CNT 0.26 wt.%) as spectral sensitizers and nonlinear optical chromophores were investigated. The third order optical nonlinearity was estimated by electric field induced second harmonic method at content of SWCNT 0.26 wt.%. The pulse Nd:YAG laser was used. Susceptibility is about 2×105 pm2/V2 or 2.3×10–29 Coulomb4×m/J3 (SI). The photoelectric and PR properties were measured at 1064 and 1550 nm with using the continuous wave lasers Nd:YAG (λ = 1064 nm) and IS550-120 (λ = 1550 nm). The quantum efficiency of charge carrier generation as a function of the applied field was estimated from the corresponding dependence of the photocurrent. The experimental values of the quantum efficiency measured at 1064 nm and 1550 nm coincident and fit Onsager equation expanded up to (E0)

4. Experimental curves correspond to quantum yield of electron - poles pairs charge ϕ0 = 0.012 with the initial separation radius r0 = 9.8 Å. It was established that photoelectric and PR properties does not react on the fullerene C60 adding. The principal PR characteristic is the gain coefficient Γ that was measured at equal intensity of the input beams I1(0) = I2(0). The net gain coefficient of object beam i.e. difference Γ – α has practical importance. Here α is the optical absorption coefficient equals 10 and 3.3 cm–1 at 1064 and 1550 nm, respectively. The gain coefficient of the signal beam equals Γ = 65 cm-1 at E = 170 V/µm and 1064 nm. At 1550 nm the net gain coefficient equals Γ – α = 59 cm-1 in the field of E = 265 V/µm. It was established that the addition of the fullerene C60 increase the gain coefficient of composites based on the unoxidized SWCNT but have not effect on the composites containing oxidized CNT. This difference may be conditioned by corresponding increasing electron affinity of SWCNT. For composites additionally containing fullerene C60 2 wt. % there was also examined the effect of the preillumination (preliminary illumination of the whole layer with 633-nm light in region of optical absorption of C60) on the PR characteristics at 1550 nm. It was established that the preillumination increases the gain coefficient. It is assumed that the holes photogenerated during preillumination fill deep traps, which impede hole transport in the absence of the preillumination. This work was supported by the ISTC (Grant No. 3718) and RFBR (project 08-03-00125).

190

ZIRCONIA NANOPARTICLES AS NEW MODEL MATERIAL FOR NANOPHOTONICS: EFFECTS OF SELF-ORGANIZATION

V.A. Lubenets, O.A. Gorban, I.L. Lyubchanskii,

I.A. Danilenko, T.E. Konstantinova

Donetsk Institute of Physics and Engineering NAS of Ukraine matscidep@aim.com

Self-organization is a well known technique for producing photonic crystals, in particular on the base of ordered colloid micro spheres [1]. Though a wide using of this method is limited by the problem of developing a stretched zone without any defects, and a perspective of its use it is directly connected with the development of physico-chemical bases of controlling the organization of nano-sized systems. It’s very interesting here to use the method of self-organization of nano-sized oxide particles with a given phase composition and surface structure to obtain ordered sufficiently large structures. Oxide nanopowders are good model objects to study self-organization processes both as consolidation of individual weakly aggregated nano-particles in a powder system and as their consolidation in nanostructured think films. We should mention that not only a size factor is important here, for these materials such constituents as structure, surface state and chemical interaction become essential. This wark has been devoted to the investigation of the self-organization processes in a weakly aggregated system of separate zirconia-based nano-particles as large as 31 nm in nano-structured films (8-20 µm in thickness) in film casting at a further drying and sintering. There are used nano-powders of ZrO2-3%Y2O3 of quadrilateral phase synthesized by co-precipitation by chloride technology with the use of extremal influences at the stage of xerogel hydrate forming [2]. By the results of X-ray diffraction analysis, the size of coherent scattering fields for this powder is 31 nm, which is in an agreement with the electronic microscopy data. By the methods of infra-red spectroscopy and visible spectrophotometry there were studied optical properties of the material and the surface state and nature of active centers were estimated. According to data obtained, the surface of such systems contains acid and basic centers of both Lewis and Brensted types. It is shown that vibrations in the IR spectral region of 1000 – 7500 sm-1 correspond to hydroxyl groups of the surface and absorbed water, and the spectrum itself shows a transparence of this material in the spectral band given. To produce films of 20 mkm in thickness there has been developed a technology of tape casting. Polyvinylbutheral was used as a binder. Film drying was done in a multistage mode at up to 1100°С; tape sintering was done at 1500°С at the rate of 3o/min. It’s shown that production of thin large ceramic films with a good surface is possible. By scanning electron microscopy there was studied the surface of these films. It was shown that a sintered ceramic film is characterized by a good homogeneous surface and has an average grain size up to 300 nm. There are discussed optical properties of a ceramic film in the above mentioned IR region. Thus, there was studied a possibility of using thin-tape casting technology for manufacturing separate fragments of a 1-D photonic crystal with needed geometrical parameters. 1. В.I. Belotelov, А.К. Zvezdin Photonnye crystal I drygie materialy. М.: Byuro, 2006. – 144 с. 2. Т.Е. Константинова, И.А. Даниленко, В.В. Токий, В.А. Глазунова Получение нанодисперсных порошков диоксида циркония. От инновации к инновации. // Наука и инновации. 2005. Т1. 3. С.76 – 87.

191

LIGHT EMITTING AND OPTICAL PROPERTIES OF SILICON-RI CH SILICON NITRIDE AND SILICON-RICH SILICON OXIDE FILM S

T. Nikitin1, L. Khriachtchev1, S. Novikov2, M. Rasanen1

1 - Laboratory of Physical Chemistry, University of Helsinki, Finland

2 - Electron Physics Laboratory, Helsinki University of Technology, Helsinki, Finland timur.nikitin@helsinki.fi

Silicon-based nanostructures have attracted a lot of attention over past two decades due to their peculiar optical properties and promises in numerous optoelectronic applications. [1] Especially the origin of 1.5 eV photoluminescence (PL) is still under intense debate. [2] We studied silicon-rich silicon oxide (SRO) and silicon-rich silicon nitride (SRN) films on silica or silicon wafer and free-standings films by means of Raman and PL spectroscopy, XPS and TEM methods. Optical properties were measured using PL filtering effect in absorbing films. [3] Reactive silicon deposition and ion implantation methods were used to fabricate thin films with varied silicon concentration. Thermal annealing produces silicon nanocrystals in the film material evidenced by Raman band at ~520 cm-1 and causes strong PL at ~1.5 eV. As a result we compared (1) SRO films with different Si amounts, (2) SRO and SRN films (i.e. containing and non-containing oxygen samples), and (3) SRO films prepared by two deposition techniques: reactive silicon deposition and ion implantation. Based on these results we discuss mechanisms of the PL and optical properties of our samples. We acknowledge R. Velagapudi and J. Lahtinen for the XPS data. The present work was supported by the FinNano Project “Optical and Surface Properties of Nanoparticles” (OPNA) [1] Silicon nanophotonics: Basic principles, present status and perspectives, edited by L.

Khriachtchev (World Scientific, Singapore, 2008) [2] L. Khriachtchev, T. Nikitin, R. Velagapudi, J. Lahtinen, and S. Novikov, Appl. Phys. Lett.

94, 043115 (2009) [3] L. Khriachtchev, T. Nikitin, C. J. Oton, R. Velagapudi, J. Sainio, J. Lahtinen, and S.

Novikov, J. Appl. Phys. 104, 104316 (2008)

192

CLUSTERING OF CADMIUM TELLURIDE QUANTUM DOTS IN A WATER SOLUTION IN THE PRESENCE OF METAL IONS:

THE ABSORPTION AND LUMINESCENT ANALYSIS

A.O. Orlova, A.V. Savelyeva, M.V. Mukhina, V.G. Maslov, A.V. Baranov, A.V. Fedorov

St.Petersburg State University of Information Technologies, Mechanics and Optics, Russia

a_v_fedorov@inbox.ru

Fabrication of the nanostructures with desired optical properties is the topical problem of nanoindustry. Semiconductor quantum dots (QDs) with characteristic sizes in order of several nanometers have appeal us the building-blocks for creating of the nanostructures using, e.g., self-organization processes in a liquid solution [1]. It is significant that due to the spatial confinement effect in QDs their optical properties are controlled by changing of the QD size [2]. Hence the optical properties of the nanostructures based on QDs can be changed too. Furthermore the possibility exists of for modifying of the optical characteristics of QDs and QD based nanostructures by a variation of type and charge of a molecular shell covering QD surface as a rule. The interesting nanostructures with some of the unusual optical properties are the clusters containing various numbers (from several units to several thousands) of QDs ordered in some extent or another. The clusters can arise as a result of spontaneous aggregation of QDs in liquid solutions. Growth of the clusters in size is generally uncontrolled and it results in their settling-out finally. Important problem is the determination of conditions for formation of the sufficiently stable clusters with certain size. It is desirable for the clusters to possess the properties that are significant for applications, e.g., the property of photoexcitation energy transfer from the cluster periphery to its center [3]. In present work an investigation of aggregation dynamics of the negatively charged CdTe QDs in a water solution in the presence of Pb2+ and Cr3+ has been performed by means the absorption and luminescent analysis included the measurements of decay times of the QD luminescence. It has been shown that the stable clusters with certain size arise in the presence of Pb ions. The photoexcitation energy transfer has been observed for the clusters of this type. 1. V.I. Roldugin, Russian Chemical Reviews 73,125 (2004). 2. A.V. Fedorov, A.V. Baranov, Optics of quantum dots. In book: Optics of nanostructures. Ed.

A.V. Fedorov. Saint-Petersburg, Nedra, 2005, P. 181-274. 3. A. Sukhanova, A.V. Baranov, T.S. Perova, J.H.M. Cohen, I. Nabiev, Angew. Chemie Int. Ed.

45, 2048 (2006).

193

SILICA NANOPARTICLES MODIFIED BY PYRYLOCYANINE DYE WITH EFFECTIVE LUMINESCENT RESPONSE

N.A. Orlova1, I.Yu. Kargapolova1, V.V. Shelkovnikov1, A.I. Plekhanov2

1 - Novosibirsk Institute of Organic Chemistry SB RAS, Russia

2 - Institute of Automation and Electrometry SB RAS, Novosibirsk, Russia vsh@nioch.nsc.ru

Polymethine dyes with electrophilic heterocycle are able to form covalent bond with nucleophile that makes possible their use for formation of luminescent chemical and biochemical labels. Especial interest have the polymethine dyes with pyrylium heterocycle forming the luminescent pyridocyanines at soft reaction conditions. The directed synthesis of functionalized pyrylocyanines to obtain the dyes connected with silica nanoparticle frame was carried out in the research. The method of modified silica nanoparticles formation with high concentration of functional dye is considered. The samples of films with silica particles modified by 4-(4'-(2''-hydroxy-3''- methoxypropoxy)styryl)-2,6-dimethylpyrylium perchlorate (1) were obtained and the reaction with buthylamine solution was studied.

OMe

CH=CH

Me

ClO4

1

O CH2-CH

OH

CH2OMe

MeNH2

EtOH, 20oC NMe

CH=CH

Me

ClO4

2

O CH2-CH

OH

CH2OMe

Me

The formation of N-alkylsubstituted pyridocyanine fluorophore on the modified silica nanoparticles was shown. The scheme of model reaction of pyridocyanine fluorophore 2 formation is shown above. The fluorophore formed on the silica nanoparticles has the green-blue luminescence with maximum at 484 nm. The initial silica nanoparticles modified by pyrylocyanine dye have in films the red-orange luminescence with maximum at 586 nm. The samples of pyrylocyanine dye connected with silica nanoparticles have good photostability. The research was practically supported by Russian federal agency science and innovation, grant 02.513.11.3167.

194

COMPARISON STUDY OF THE NONLINEAR OPTICAL PROPERTIE S OF MOLECULAR J- AND H- AGGREGATES IN THIN SOLID FIL MS

A.I. Plekhanov1, A.I. Gorkovenko1, N.A. Orlova2,

A.E. Simanchuk1, V.V. Shelkovnikov2

1 - Institute of Automation and Electrometry SB RAS, Novosibirsk, Russia 2 - Novosibirsk Institute of Organic Chemistry SB RAS, Russia

fractal@iae.nsk.su

The interest to the optical and nonlinear optical properties of organic molecular aggregates determined by possibility of the application of organic nanostructures in modern optoelectronic technologies. It is known that such structures possess the giant nonlinearity (χ(3)~ 10-5 esu) with a subpicosecond relaxation times at a resonant condition [1] compared with other organic system. High nonlinear-optical response of aggregated dyes and preparation technique based on self-assembly of dyes make these mediums perspective for optical modulations [2,3]. The most attention is given to the optical and nonlinear optical properties of J- aggregates. At the same time the studies of molecular H-aggregates are limited the questions of synthesis and optical properties. We have studied and compared the dispersion of nonlinear absorption coefficient of the molecular J- and –H-aggregates within the exciton absorption bands in spectral range 645-670 nm at first time. Thin films of J- and H-aggregates were prepared by spin-coating dye solution of thiacarbocyanine dye BT-C18-H for J-aggregates and styryl type thiaflavylium dye DT-3 for H-aggregates on 1 mm glass substrate and had exiton absorption bands at 645 nm and 670 nm, respectively. The thickness of the samples was measured by spectral ellipsometry technique and was about 10 nm. The optical density of the samples was about 0.3-0.4 at the exciton absorption band. The study of nonlinear optical properties was carried out with Z-scan open aperture technique. We have used an optical parametric oscillator (“Solar”) with 15 ns pulse duration as a source of radiation. The sensitivity of our experimental setup allowed measuring the relative bleaching of 0.5 %. The nonlinear absorption coefficient measurements were carried out in 625-690 nm spectral range for both types of the samples. We have measured the dispersion of nonlinear absorption coefficient of the thin solid films of molecular J- and –H-aggregates. The nonlinear absorption coefficient at the exciton band maximum for J-aggregates turned out to be β = -90 cm/kW (saturation intensity Is = 3.5 МВт/см2) and β =-100 см/кВт (Is = 7 МВт/см2) for H-aggregates. Taking into account the difference of the excitonic band widths we have concluded that the nonlinear optical response of different types of the aggregated samples are the same order of magnitude. In both cases of the J-aggregates and H-aggregates samples the frequency dependence of the nonlinear absorption coefficient had found to be narrow than linear absorption that is in a good agreement with the theoretical model of two level system.

1. R.V Markov., P.A.Chubakov, A.I.Plekhanov, et al., Nonlinear Optics. 2000 v.25, p. 365. 2. Kuch'yanov A.S., Markov R.V., Plekhanov A.I., Simanchuk A.E., Avdeeva V.I., Shapiro

B.I., Slominskii Yu.I., Tolmachev A.I., Optics Communs. 2004. v. 231, p.343. 3. M. Furuki, S. Tatsuura, O. Wada, M. Tian, Y. Sato, L. S. Pu. IEICE Trans. Electron. 2000.

E83-C, p.974.

195

LARGE ANGULAR DISPERSION EXPERIENCED BY A LIGHT BEAM IN PASSING THROUGH THE BOUNDARY

OF A GLASS SUBSTRATE – PHOTON CRYSTAL

A.I. Plekhanov, A.A. Zabolotskii, A.S. Kuchyanov

Institute of Automation and Electrometry SB RAS, Novosibirsk, Russia fractal@iae.nsk.su

Photonic crystals (PhC) [1] have inspired a lot of interest due to their potential for controlling the propagation of light. The most of PhC applications are based on the use of their photonic band gap. There are other applications based on the anomalous dispersion behavior of PhC, named the superprism effect [2]. In the experiment [3] the PhC was fabricated by depositing alternate layers of amorphous Si and SiO2 on a patterned Si substrate having a hexagonal array of holes. Under certain conditions the light path shows a drastic wide swing with a slight change of the incident light angle owing to the strong modification of group velocity at 1,5 -µm- wavelength range. We have found the effect of a strong angular dispersion (~3 nm/deg) if one shines a white light (300-700 nm) on the boundary between a glass substrate and PhC film. In this case we have observed two dispersed light beams. One of them leaves the PhC film and another reflects back in a glass substrate. The PhC films are fabricated on a glass substrate (with n =1.51) in a suspension of SiO2 by dynamic meniscus method [4]. We have found the following features of the effect that differ from the "superprism" effect. In our case we have not observed any refraction when the radiation incident on the surface of a PhC film at any angle from air. We have found that the extremely large angular dispersion experienced by a light beam when entering a PhC film from a glass substrate. In our case the light path does not show a drastic wide swing with a slight change of the incident light angle. The value of average angle of dispersed light beam varies only slightly. We have observed that our effect is almost insensitive to a dielectric contrast in contrast to the superprism effect. We have found the azimuthal anisotropy of the effect is due to a hexagonal packing of PhC layers. Thus, for the first time the effect of the extremely large angular dispersion experienced by a light beam was observed when a light beam incident on the boundary of a glass substrate - PhC film. The effect was observed for a visible spectral range. The observed phenomenon is due to effective optical diffraction on PhC planes when a light beam is propagating in an optical dense (glass) substrate in which the wavelength of light is less by a factor n. This study was supported by the integration project of the SB RAS 17 and by the Program 8 of Physical Sciences Division of the RAS.

1. E. Yablonovich. Phys.Rev.Lett. 1987, vol. 58, p.2059. 2. H. Kosaka, et. al., Phys. Rev. B, 1998, vol. 58, p.10096. 3. H. Kosaka, et al. J. Lightwave Technol. 1999, vol. 17, p.2032. 4. А.И. Плеханов, Д.В. Калинин, В.В. Сердобинцева. Российские нанотехнологии,

2006, т.1, 1, с. 245.

196

PHOTONIC BAND GAP IN PHOTONIC CRYSTAL FORMED BY THE HOLOGRAM

A.S. Shcheulin, A.E. Angervaks, A.K. Kupchikov, A.I. Ryskin

St.Petersburg State University of Information Technologies, Mechanics and Optics State

University of Information Technologies, Mechanics and Optics, Russia angervax@mail.ru

For a multi-layer slab that consists of layers of (a – d) and d thickness and ε and (ε + ∆ε) dielectric susceptibility, respectively, homogeneous in the xy plane and alternating in z direction (a model of 1D photonic crystal), the ratio of photon band gap width, ∆ω, to its average value, ωm,

( ).

/sin

a

ad

m

πεε

ωω ⋅∆≈∆

(1)

The ratio (1) is valid for small ∆ε and d/а values. It is evident from (1) that for 1D photonic crystal the band gap do exist for any small values of two above-mentioned parameters. We have observed this gap in the space distribution of optical radiation of the fluorescent 1D photonic crystal formed by hologram written in the CaF2:Na crystal. The as-grown crystal was annealed in the reduction atmosphere of the calcium vapors (an “additive coloration” procedure). As a result of this procedure various color centers are formed in the crystal volume. The hologram was written at high temperature in 18×10×12 mm specimen that was cut out of the colored crystal. At the hologram writing optical properties of the crystal is modulated due to space modification of the color center concentration. The subsequent illumination of the crystal with the appropriate radiation transforms the most of the centers into the luminescent +

AM -centers (λmax = 760 nm). The space frequency of the hologram was equal to 1/2 of the reciprocal wavelength of the luminescence band maximum corrected for the crystal refractive index. Such specimen may be considered as 1D photonic crystal, for which propagation of 760 nm radiation (wavelength in vacuum) along the direction perpendicular to the hologram plane (xy) is forbidden due to existence of the photonic band gap. The luminescence of the specimen was excited by He-Ne laser radiation. The optical scheme allowed detecting the space distribution of the luminescence at CCD camera plane, which was parallel to the hologram plane. A pit in the distribution

corresponding to z-direction (Fig. 1) shows the above prohibition. The prohibition refers not only to the band maximum but to an adjusting spectral range. The range width, which is determined by a spectral selectivity of the hologram, is relatively narrow as compared with half-width of the luminescence band (~120 nm at room temperature). Therefore, the pit has the relatively small amplitude. Figure 1. Distribution of +

AM -center luminescence in CaF2:Na specimen with hologram at CCD camera plane. Numeralization of x and y axes shows the corresponding pixel number.

197

STRUCTURAL ASPECT OF NANOPHOTONICS OF FULLERENE SOLUTIONS

E.F. Sheka1, B.S. Razbirin2, A.N. Starukhin2, D.K. Nelson2,

M.Yu. Degunov2, P.A. Troshin3, R.N. Lyubovskaya3, V.P. Fazleeva4, V.P. Gubskaya4, I.A. Nuretdinov4

1 - Peoples’ Friendship University of the Russian Federation, Moscow, Russia

2 - A.F. Ioffe Physical-Technical Institute RAS, St.Petersburg, Russia 3 - Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia

4 - A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan RC RAS, Kazan, Russia sheka@icp.ac.ru

The fullerene ability to form clusters in diluted solutions causes exciting spectral properties of these matrices providing an enhancement of both the emission spectra and nonlinear optical response [1-3]. Hereinafter, “fullerene” is related to both С60 and its derivatives. Being common for solutions, the molecule clusterization and, as a consequence, a potential ability to use the solution as an active nonlinear optical (NLO) matrix depends crucially from the fullerene molecule chemical structure. When pursuing a goal of a selection of an NLO matrix with required NLO characteristics, a researcher faces the problem of sorting a great number of derivatives, both already available and newly to be synthesized. Obviously, the lack of a priori criteria results in a considerable finance and time expenses. That is why the availability of a reliable and, even more, a priori testing is of extreme importance. The paper presents two ways of the problem solution based on empirical and computational investigations [1-3]. In the first case, the testing reduces the problem to looking for an extra blue emission in the visible part of spectra. The intense emission witnesses reliably good NLO properties of the tested matrix. The second approach is based on quantum-chemical calculations and can serve as a priori testing which can be followed afterwards by a synthesis of the fullerene with required properties. The testing is based on the fact that the formation of stable clusters is fully determined by the energy of pairwise interaction cplE of fullerene molecules (sol-sol

clusters) and the fullerene and solvent molecule (sol-solv clusters). Stable clusters which enable to provide the enhancement of the local electric field of both incoming and outgoing light are formed if only cplE is negative and large by absolute value. The latter directly correlates with the

efficacy of the NLO response of the matrix considered. The two approaches are proven by testing a set of matrices with different derivatives of fullerene C60, both already available and purposely synthesized for the current study. The work is financially supported by the RFBR (grants 07-03-00755 and 08-03-01006). References

1. B.S.Razbirin, E.F.Sheka, A.N.Starukhin, D.K.Nelson, P.A.Troshin, and R.N.Lyubovskaya, JETP Lett. 87, 133-139 (2008)

2. E.F.Sheka, B.S.Razbirin, A.N.Starukhin, D.K.Nelson, L.N.Lyubovskaya , and P.A.Troshin, JETP. 135, No.5 (2009)

3. E.F.Sheka, B.S.Razbirin, A.N.Starukhin, D.K.Nelson, P.A.Troshin, R.N.Lyubovskaya, abd N.V.Kamanina, arXiv:0901.3728v1 26 January 2009.

198

MONODISPERSE POLYMERIC NANOPARTICLES MODIFIED WITH CYCLODEXTRINS AND DYES

N.N. Shevchenko, A.Yu. Menshikova, I.V. Noskova,

B.M. Shabsels, A.V. Yakimansky

Institute of Macromolecular Compounds RAS, St.Petersburg, Russia nata_non@hq.macro.ru

Recently, the inclusion compounds with dyes have attracted a great attention, since the dyes can remarkably change their spectral features (absorption or emission) being included as the guest molecules. So, cyclodextrins as host molecules can be used together with dyes to design novel responsible materials for chemisensorics. The interior of cyclodextrins is considerably less hydrophilic and able to host the most of hydrophobic dyes and hide them from aqueous media. This approach was applied to attach some dyes to the surface of monodisperse polymeric particles. One-step batch emulsion copolymerization of methyl methacrylate and N-vinylformamide (NVF) initiated by 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride in the presence of α-, β-, or γ-cyclodextrins as a surface modifiers was applied to obtain monodisperse particles. These particles had both positive surface charge and quite hydrophilic surface. Variation in the concentration of cationic initiator, temperature, and pH of reaction mixtures allowed preparing monodisperse latexes with particle diameters in the range of 220-270 nm and their mean-root-square deviation below 2%. To diminish the particle size down to 50 nm a cationic surfactant, cetyltrimethylammonium bromide, was added in the reaction mixtures. After rinsing by dialysis or successive centrifugation/redispersion in pure water, the surface of obtained particles was hydrolyzed in acidic media. As a result, particle surface coated by grafted cyclodextrin molecules also contained amino groups originated from NVF units along with carboxylic groups from hydrolyzed initiator residues. The ζ-potential of all obtained particles had the high positive values in the wide pH range. In dialyzed dispersions of nanoparticles (100 nm in diameter) the formation of periodic colloid structures was observed. It was exhibited as iridescence of the separate ordered structures with the cross-section square of ~5 mm2. The particles of 250 nm in diameter was capable of self-assembling into periodic three-dimensional ordered structures, which demonstrated photonic crystalline features. Adsorption of Eosin, Fluorescein, or Rodamin 6G on the particle surface was investigated. The changes in luminescence spectra of the dyes incorporated into particle surface in the presence of acetone were revealed. This finding is a good promise for the usage of such particles modified with cyclodextrins and dyes as sensor elements for chemisensorics. The work is supported by the Federal Agency on Science and Innovation of the Russian Federation (contract 02.513.12.3025) and by the Scientific Program “Basic research of nanotechnology and nanomaterials” of the Presidium of the Russian Academy of Sciences.

199

RELATIONSHIP BETWEEN WATER VAPOR PRESSURE OF REVERSE MICELLAR SYSTEM AND REVERSE MICELLES SIZE DISTRIBUT ION

S.A. Tovstun, V.F. Razumov

Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia

tovstun_sergey@rambler.ru

Multiple chemical equilibrium approach was used to derive an equation which relates reverse micelles size distribution to their aggregation numbers and water vapor pressure above solution. No assumptions about functional relations between surface tension and size or size and composition have been used. Experimental data on reverse micellar solution of aerosol-OT available in literature have been used to calculate the polydispersity with the aid of the equation obtained. It was found that the polydispersity of aerosol-OT reverse micelles is in the range of 6-15%, depending on data used.

200

THE STUDY OF ENDOTAXIAL NANOSTRUCTURIZATION OF POLY(3-HEXYLTHIOPHENE)/FULLERENE COMPOSITE

BY LIGHT-INDUCED ESR SPECTROSCOPY

E.I. Yudanova, V.I. Krinichnyi

Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia yudan@icp.ac.ru

Efficiency of polymer based solar cells is much higher when bulky heterojunctions of interpenetrating nets of electron donor and electron acceptor materials are used. The most promising compounds were found to be organic conjugated polymer - poly(3-hexylthiophene (P3HT), and fullerene derivative – [1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61] (PCBM). Photoinduced charge transfer in P3HT/PCBM bulky heterojunctions is accompanied by the formation of a radical pair – polaron and a fullerene radical anion with S = ½. Therefore, relaxation and dynamic properties of such paramagnetic centers can be investigated using light-induced ESR spectroscopy (LESR). The ordered chain structure of P3HT can perform as a center of nanostructurization of polymer molecules to two-dimensional layers via interchain alignment. It was shown in [1] that self-organization of macromolecules upon regioregular P3HT temperature annealing improves charge carrier mobility by more than two orders of magnitude. However, nanostructurization can essentially be different in the starting polymer and in the P3HT/PCBM composite matrix because of the effect of fullerene molecules on self-organization of the polymer chains. The goal of this investigation was to study the effect of thermal modification of the P3HT/PCBM composite on dynamic and kinetic properties of photoinduced charge carriers. The analysis of the magnetic, relaxation and dynamic parameters of polarons and fullerene radical anions induced in the bulky heterojunction of the starting P3HT/PCBM composite and the temperature annealing P3HT/PCBM composite by white light at different temperatures in a wide (77 – 300 K) range showed that charges carriers in a radical pair do not interact. Thus, they interact differently with their microenvironment. This allowed us to separately determine magnetic, relaxation and dynamic parameters and identify the recombination and dynamics mechanism for both types of charge carriers in the P3HT/PCBM bulky heterojunction. It was shown that the interaction of polarons with the lattice is defined by its phonon energy, Eph, while rotational diffusion of fullerene can be described in the frames of the Elliot model of activation electron transfer through energy barrier, Eb. The calculation showed the Eph and Eb values to be essentially lower after composite temperature annealing. The temperature dependences of diffusion coefficients were calculated using polaron movement along and across polymer chains and rotational diffusion of fullerene molecules. The decrease of anisotropy of polaron mobility after thermal modification of the composite was found. This is evidence of higher effective crystallinity of the polymer matrix. Composite heating provides nanostructurization of the bulky heterojunction in the P3HT/PCBM composite as a result of the formation of fullerene and polymer crystalline network and, hence, improves electronic properties of such plastic solar cells. 1. Sirringhaus H., Brown P.J. et.al.// Nature,1999, v. 401, p.685-688.

201

ELECTROOPTICAL PROPERTIES OF POLARIZATION HOLOGRAPH Y GRATINGS IN POLYMER DISPERSED LIQUID CRYSTALS

G.M. Zharkova, S.A. Streltsov, A.P. Petrov, V.M. Khachaturyan

S.A. Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia

Zharkova@itam.nsc.ru

Liquid-crystal composites (LC-composites) present a polymer matrix, in its volume the capsules of nematic liquid crystals (NLC) are dispersed. Polarization holographic gratings were produced in the LC-composites by exposing the liquid crystal-prepolymer syrup to a light pattern obtained by superposition of two waves having orthogonal linear polarization. In this case, the phase difference variation between two interfering beams results only in the variation of the NLC polarization state. Since the NLC is able to orient toward the resulting field, after the exposure a grating with repeating NLC-orientations forms in the polymer capsules. Such composite materials are promising because of the possibility of a relative simple one-stage technology of the optical record, long-time storage of the polarization state, which provides the high polarization selectivity and the possibility to control their optical properties with an electric field [1–2]. Electrooptical properties of such gratings depend on the LC-composite morphology, its geometrical sizes, and parameters of the controlling electrical field. The purpose of the work was to study experimentally the diffraction efficiency of the polarization holographic gratings, their response time dependence on the geometrical parameters of the LC-composite and controlling field parameters. The radiation source during the polarization holographic grating record was a semi-conductive laser with λ = 658 nm and power of 80 mW. The pre-polymer composition presented a mixture of the NLC, acrylate monomer, binding component and a photo-initiating system. The grating spacing was of 19 micrometers. The dependencies of the diffraction efficiency of the polarization holographic grating on the controlling electric field strength were obtained at the incidence of the linearly polarized light on the grating at the Bragg’s angle. The dependencies of the turn-on times and relaxation times on the sample thickness and frequency of the controlling electric field are presented. Calculation and experimental data are compared. It is shown that at the same modes of control, the turn-on times of the studied grating are shorter than the turn-on times of the polymer liquid-crystal diffraction grating [3], which is caused by the better stability of the formed structure of the LC-composite at the record of the polarization holographic grating Reference: 1. G.P. Crawford, J.N. Eakin, M.D. Radcliffe, A. Callan-Jones, R.A. Pelcovits .Liquid-crystal

diffraction gratings using polarization holography alignment// J. Appl. Phys. – 2005, vol. 98, p.123102.

2. A.Y.-G. Fuh, C.-R. Lee, C.-T. Cheng. Fast optical recording of polarization holographic grating based on an azo-dye-doped polymer-dispersed liquid crystal film// Jap. J. Appl. Phys. – 2003, vol. 42. – pp.4406-4410.

3. G. М. Zharkova, А. P. Petrov,.В. I. V. Samsonova, S. А. Strel’tzov, V. М. Khachaturyan. Polarization characteristics of the polymer liquid-crystal gratings // The Optical Journal. – 2008, Vol. 75, No. 8. – pp.48–52.

202

INDEX Abakumov G.A. ..................................................... 117 Adamov G.E. ......................................................... 121 Adamova D.A. ....................................................... 121 Adrianov V.E. .......................................................... 70 Afanasiev A.V. ........................................................ 15 Ageev L.A. ............................................................... 90 Aiboushev A. ........................................................... 16 Aimukhanov A.K. .................................................... 57 Ait A.O. ........................................................... 79, 122 Ajiki H. .................................................................... 20 Akimkin T.M. ................................................ 118, 123 Alekseeva V.I. ......................................................... 58 Alexandrov A.P. ...................................................... 15 Alexeenko Yu.S. ...................................................... 76 Alfimov M.V.43, 47, 56, 61, 74, 78, 95, 148, 161,

166, 170 Andreev A.S. ......................................................... 124 Angervaks A.E. ...................................................... 196 Anisimov A.V. ................................................. 62, 156 Antipin V.A. ...................................................... 45, 66 Arabei S.M. ............................................................ 137 Arslanov V.V. ........................................................ 156 Artemyeva E.S. ...................................................... 125 Artyukhov V.Ya. ....................... 35, 94, 127, 128, 142 Astafiev A. ............................................................... 16 Avakayn V.G. .......................................................... 95 Avilov A.S. ............................................................ 183 Babenko S.D. ............................................. 77, 88, 185 Bagaturyants A.A. ................................................... 74 Balakai A.A. .......................................................... 185 Balakina M.Yu. .................................................. 46, 53 Barachevsky V.A. .............................. 79, 96, 122, 136 Baranov A.V. ........... 17, 19, 70, 80, 89, 130, 165, 192 Baranov D.A. ......................................................... 183 Barinov A.V. .................................................. 105, 106 Basilevsky M.V. ................................................ 47, 78 Basov L.L. ............................................................. 126 Batenkin M.A. ......................................................... 48 Baulin V.E. ........................................................ 49, 85 Bazyl O.K. ..................................................... 127, 128 Belikov N.E. .................................................. 131, 136 Belyakov L.V. .......................................................... 92 Berlin A.A. ............................................................... 79 Besugliy S.O. ........................................................... 73 Besuglui S.O. ........................................................... 76 Bikovskaya V.S. .................................................... 169 Bityurin N.M. ........................................................... 15 Bobyleva A.V. ....................................................... 156 Bodunov E.N. ........................................................ 129 Bogdanov G.N. ...................................................... 106 Bogdanova I.V. ........................................................ 34 Borisov A.V. ............................................................ 39 Borshchev O.V. ....................................................... 33 Brichkin S.B. ................................................. 164, 186 Budyka M.F. ............................................................ 97 Bugaychuk S. ..................................................... 22, 63 Bulanin K.M. ......................................................... 152 Butenin A.V. .......................................................... 132 Charushin V.N. ...................................................... 147 Che M. ................................................................... 144

Cherevkov S.A. ........................................................ 17 Chernyadyev A.Yu. ................................................. 50 Chernyshev A.V....................................................... 51 Chesnokov S.A. ............................................... 48, 117 Chibisov A.K. .......................................................... 98 Chizhov Yu.V. ............................................... 108, 124 Chmereva T.M. ...................................................... 110 Chubakov P.A. ....................................................... 173 Chubakov V.P. ....................................................... 173 Chumakov D.E......................................................... 62 Coluccia S. ............................................................. 144 Danilenko I.A. ........................................................ 190 Danilov V.V. .......................................................... 130 De Kok M. ............................................................... 36 Degtyarenko K.M. ....................................... 23, 54, 65 Degunov M.Yu. ..................................................... 197 Dembo К.А. ........................................................... 183 Demina O.V. .................................................. 131, 136 Denisov N.N. ........................................................... 24 Derkacheva V.M. ................................................... 132 Devadze L. ............................................................. 135 Dmitriev A.V. .......................................................... 69 Dmitrieva S.N. ....................................................... 161 Dorogan I.V. ............................................................ 76 Druzhinin A.V. ...................................................... 147 Druzhkov N.O. ....................................................... 117 Dubtsov S.N. ............................................................ 40 Dudar S.S. .............................................................. 180 Dultseva G.G. .......................................................... 40 Dushkin A.V. ..................................................... 32, 52 Dyachuk O.A. ........................................................ 143 Dzhagarov B.M. ....................................................... 99 Egorova A.V. ........................................................... 23 Eliseeva S.V. ............................................................ 82 Elyashevich G.K. ................................................... 130 Emeline A.V. ......................................... 100, 154, 155 Enakieva Yu.Yu. .................................................... 172 Eremina N.S. ................................................ 23, 54, 65 Ermolaev V.L......................................................... 180 Ermolaeva G.M. ....................................................... 92 Ermolina E.G. ................................................ 101, 137 Evseenko V.I. ........................................................... 52 Evseeva T.G. .................................................... 43, 170 Fazleeva V.P. ......................................................... 197 Fedorenko S.V. .................................................. 18, 30 Fedorov A.V. ......................... 17, 19, 70, 80, 165, 192 Fedorov Y.V. ......................................................... 156 Fedorova O.A. ........................................................ 156 Fedorova O.V. ........................................................ 147 Fedorova T.M. ....................................................... 132 Fedotov V.G. .......................................................... 175 Fominykh O.D. ........................................................ 53 Freidzon A.Ya. ....................................................... 161 Gadirov R.M. ............................... 23, 54, 65, 101, 133 Gaeva E.B. ............................................................... 51 Gak V.Yu. ...................................................... 164, 186 Galinovski N.A. ....................................................... 65 Garbovskiy Y. .......................................................... 22 Garbovskiy Yu. ........................................................ 63 German A.E. ............................................................ 90

203

Godovsky D.Yu. ...................................................... 55 Golubkov D.V. ......................................................... 56 Gontareva N.B. ...................................................... 102 Gorban O.A. ........................................................... 190 Gorbunova Yu.G. ................................................... 172 Gorelik A.M. .......................................................... 122 Goriuchko V.V. ..................................................... 115 Gorkovenko A.I. .................................................... 194 Goryachev A.E. ....................................................... 41 Goryachev N.S. .............................................. 105, 106 Gostev F.E. .............................................................. 38 Grebennikov E.P. ................................................... 121 Grigoriev F.V. .......................................................... 47 Grigoriev V.V. ....................................................... 106 Grishina A.D. ................................................. 172, 189 Grodzyuk G.Ya ........................................................ 83 Gromov S.P. ............................................. 43, 161, 166 Gubin S.P. .............................................................. 183 Gubskaya V.P. ....................................................... 197 Gurinov A.A. ................................................. 150, 151 Gurinovich V.V. .................................................... 134 Hakina E.A. ............................................................. 84 Hoppe H. .................................................................. 41 Ibrayev N.Kh. .................................................... 57, 58 Iida T. ....................................................................... 20 Inganas O. ................................................................ 55 Ionov D.S. ................................................................ 61 Ishchenko A.A. ...................................................... 128 Ishihara H. ................................................................ 20 Ivanchikhina A.V. .......................................... 167, 187 Ivanov D.A. ............................................................. 56 Ivanov V.B. ............................................................ 104 Ivanova S.S. ........................................................... 137 Izmodenova S.V. ................................................... 168 Japaridze K. ........................................................... 135 Kalashnikova I.P. ................................................... 137 Kaliya O.L. ............................................................ 132 Kaplunov M.G. .................................................. 67, 87 Kargapolova I.Yu. ................................................. 193 Kashin A.S. ............................................................ 118 Kataeva G.V. ................................................. 154, 155 Kazakov V.P. ..................................................... 45, 66 Kazansky V.B. ....................................................... 103 Keshtov M.L. ........................................................... 59 Khachaturyan V.M. ....................................... 184, 201 Khakina E.A. ..................................................... 41, 60 Khamova T.V. ......................................................... 75 Khavina E.Yu. ....................................................... 104 Khlebunov A.A. ....................................................... 61 Khodonov A.A. .............................................. 131, 136 Khodos I.I. ............................................................. 183 Khoroshutin A.V. ..................................................... 62 Khrebtov A.I. ......................................................... 130 Khriachtchev L. ............................................... 21, 191 Kislov D.A. ............................................................ 110 Kispert L.D. ............................................................. 32 Klimusheva G. ................................................... 22, 63 Klinskikh A.F. ....................................................... 111 Kluyev V.G. ............................................................. 31 Klyuev V.G. ........................................................... 169 Knyukshto V.N. ....................................................... 93 Kobeleva O.I. ......................................................... 122 Kochubey V.I. ................................................ 143, 188

Koetse M.M. ............................................................ 36 Kol’tsova L.S. .......................................................... 91 Kolesnik I.N. ............................................................ 65 Kolesnikov M.P. .................................................... 119 Komarov P.V. .......................................................... 61 Konarev D.V. ........................................................... 60 Kondo T. .................................................................. 27 Kondracki B.A. ........................................................ 64 Konev A.N. .............................................................. 48 Konovalov A.I. .................................................. 18, 30 Konovalova O.D. ............................................... 18, 30 Konovalova T.A....................................................... 32 Konstantinov N.Y. ................................................... 49 Konstantinova T.E. ................................................ 190 Konyukhova Ju.G. ................................................. 188 Kopylova T.N. ............................... 23, 35, 54, 65, 133 Korolev V.V. ............................................................ 71 Korotkov V.I. ......................................... 146, 150, 151 Korovin Yu.V. ....................................................... 101 Koshkin A.V. ............................................. 43, 61, 170 Kosjakova E.A. ........................................................ 31 Kotelnikov A.I. .............................................. 105, 106 Kotelnikova R.A. ................................................... 106 Kotova O.V. ....................................................... 82, 85 Kovalev A.A. ..................................................... 45, 66 Krasnaya Zh.A. ...................................................... 158 Krasnikova S.S......................................................... 67 Krasnovsky A.A..................................................... 107 Krauklis I.V. .................................................. 108, 115 Krinichnyi V.I. ................................................. 24, 200 Kritsky M.S. ................................................... 109, 119 Krivenko T.V. ................................................ 172, 189 Kruchinin A.U. ........................................................ 64 Kruchinin N.Y. ...................................................... 168 Kruchinin S.Yu. ............................................... 19, 165 Kruijt P.G.M. ........................................................... 36 Kryukov A.I. .......................................................... 179 Kucherenko M.G. .......................................... 110, 168 Kuchmiy S.Ya. ................................................. 83, 179 Kuchyanov A.S. ............................................. 174, 195 Kukhta A.V. ............................................................. 25 Kukhto A.V. ....................................................... 23, 65 Kukhto I.N. .............................................................. 65 Kupchikov A.K. ..................................................... 196 Kurbangaleev V.R. ................................................ 121 Kurskii Yu.A. ......................................................... 117 Kuz’mina L.G. ....................................................... 161 Kuzicheva E.A. ...................................................... 102 Kuzmin G.N. .......................................................... 154 Kuzmina L.G. ........................................................ 166 Kuzmina N.P. ..................................................... 82, 85 Kuznetsova R.T. ............................................ 101, 137 Kvashnina N.V. .............................................. 111, 114 Kvyatkovskii O.E. ................................................... 92 Lachinov A.N. .................................................... 45, 66 Laptenkov D.V. ...................................................... 138 Laptev A.V. .................................................... 131, 136 Latyshev A.N. .......................................... 31, 111, 114 Leonova L.Yu. ......................................................... 31 Lepeshkevich S.V. ................................................... 99 Lepnev L.S. ........................................................ 82, 85 Leshina T.V. ............................................................ 32 Lesnichin S.B. ................................................ 150, 151

204

Levin P.P. ......................................................... 91, 159 Lisachenko A.A. .................... 112, 126, 139, 140, 144 Litke S.V. ............................................................... 125 Lobach A.S. ............................................................. 87 Lobo R.F. ............................................................... 152 Logacheva N.M. ...................................................... 49 Logis A.G. ............................................................. 133 Loukova G.V. ........................................ 113, 141, 162 Lukin A.Yu. ................................................... 131, 136 Lukov A.V. ............................................................ 141 Lukovskaya E.V. ................................................... 156 Lukyanov B.S. ................................................... 76, 90 Lupicov D.I. ............................................................. 75 Lupikov D.I. ............................................................. 68 Luponosov Y.N. ....................................................... 33 Lybenets V.A. ........................................................ 190 Lypenko D.A. ........................................ 26, 59, 69, 81 Lyssenko K.A. ......................................................... 82 Lyubchanskii I.L. ................................................... 190 Lyubovskaya R.N. ..................................... 60, 88, 197 Maiorova T.L. ........................................................ 169 Maisuradze D. ........................................................ 135 Maksimchuk N.V. .................................................... 39 Mal’tsev E.I. ............................................................ 81 Malkin V.M. .......................................................... 115 Maltsev E.I. .................................................. 26, 59, 69 Mamedov M. ............................................................ 38 Mardaleishvili I.R. ................................................... 91 Marinina L.E. ........................................................... 58 Marinov I.L. ................................................... 116, 153 Martra G. ................................................................ 144 Maskevich S.A. ................................................ 90, 178 Maslov V.G. ................. 17, 70, 80, 146, 150, 151, 192 Maslova E.A. ......................................................... 115 Masuda H. ................................................................ 27 Masuhara H. ............................................................. 28 Matveeva A.G. ......................................................... 71 Mayer G.V. ........................ 23, 94, 101, 127, 137, 142 Medvedev E.S. ....................................................... 105 Melnikov A.G. ....................................................... 143 Melnikov G.V. ....................................................... 143 Menshikova A.Yu. ........................... 43, 170, 175, 198 Mensov S.N. ...................................................... 48, 72 Meshkov A.M. ....................................................... 146 Meshkova S.B. ......................................................... 23 Meteleva E.S. ..................................................... 32, 52 Metelitsa A.V. .................................................... 51, 73 Meulendijks N.N.M.M. ........................................... 36 Micheau J.C. ............................................................ 29 Mikhaylov R.V. ..................................... 138, 140, 144 Milov A.D. ............................................................... 42 Minakov D.A. ........................................................ 114 Minibaev R.F. .......................................................... 74 Minkin V.I. ........................................................ 51, 73 Mirnaya T. ......................................................... 22, 63 Mishchenko D.V. ................................................... 106 Mochalova A.E. ....................................................... 15 Molodid S. ............................................................. 177 Morozov V.A. ........................................................ 145 Moskvin Yu.L. ....................................................... 185 Movchan T.G. .................................................... 68, 75 Mukhanov E.L. ........................................................ 76 Mukhina M.V. ......................................... 19, 165, 192

Mustafina A.R. ................................................... 18, 30 Muzafarov A.M. .......................................... 33, 77, 84 Myshkovskaya E.N. ................................................. 77 Nadolinskaya S.S. .................................................. 146 Nadtochenko V. ....................................................... 16 Nadtochenko V.A. ................................................... 38 Nakaryakov A.S. ...................................................... 45 Naumova E.V. ........................................................ 143 Nazarov V.B. ........................................................... 95 Nelson D.K. ........................................................... 197 Nevidimov A.V. ..................................................... 171 Nikitin T. ................................................................ 191 Nikitina E.A. ...................................................... 47, 78 Nikolaichik V.I. ..................................................... 183 Nikolenko D.Yu. ............................................ 164, 186 Nikolenko L.M....................................................... 167 Nikonorova N.A....................................................... 43 Nikonov S.Yu. ....................................................... 133 Noskova I.V. .......................................................... 198 Nosova G.I. .............................................................. 43 Novikov S. ............................................................. 191 Nuretdinov I.A. ...................................................... 197 Odinokov A.V. ......................................................... 78 Optov V.A. ............................................................... 79 Orlova A.O. ............................ 17, 70, 80, 89, 130, 192 Orlova N.A. .................................................... 193, 194 Ortega J.M. ............................................................ 105 Os’kina O.Yu. .......................................................... 91 Ovchinnikov O.V. .................................................... 31 Ovchinnikova I.G................................................... 147 Ovtchinnikov O.V. ......................................... 111, 114 Panova I.G. ............................................................ 159 Pavich T.A. ............................................................ 137 Peregudov A.S. .................................................. 41, 60 Peregudova S.M. ...................................................... 60 Perelygina O.M. ................................................. 26, 81 Pereshivko L.Ya............................................. 172, 189 Petrov A.P. ..................................................... 184, 201 Petrov N. Kh. ........................................................... 78 Petrov N.Kh. ............................................................ 56 Petrova E.G. ........................................................... 132 Pham Thi Hai M. ................................................... 169 Plachev Yu.A. .................................................... 34, 50 Plekhanov A.I. ............................... 173, 174, 193, 195 Pleshkov D.N. .......................................................... 82 Plotnikov V.G. ....................................................... 148 Plyusnin V.F. ........................................................... 71 Pokhodenko V.D. ................................................... 179 Polushtaytsev Yu.V. ................................................ 72 Polyakov N.E. .................................................... 32, 52 Ponomarenko S.A. ....................................... 33, 77, 84 Poretskiy M.S......................................................... 149 Pozin S.I. ............................................................ 26, 59 Pravdin A.B. .......................................................... 143 Prokhorov V.V. ........................................................ 81 Pronkin P.G. ........................................................... 160 Raevskaya A.E. ........................................................ 83 Raitman O.A. ......................................................... 156 Rapoport V.L. ................................................ 108, 115 Rasanen M. ............................................................ 191 Rasshchepkina N.A. ................................................. 86 Razbirin B.S. .................................................. 176, 197 Razumov V.F. ............................ 41, 88, 164, 186, 199

205

Rensing P.A. ............................................................ 36 Revina A.A. ............................................................. 34 Reznikov V.A. ......................................................... 71 Romanova V.S. ...................................................... 106 Rozhkova J.A. ................................................ 150, 151 Rudakova A.V. ...................................... 116, 152, 153 Rudyak V.Y. ............................................................ 95 Rusakova N.V. ....................................................... 101 Rusinov G.L. .......................................................... 147 Ryabchuk V.K. ...................................... 152, 154, 155 Ryashin O.N. ........................................................... 76 Ryazanov M.I. ....................................................... 182 Rybkin A.Yu. ......................................................... 106 Rychwalski R.W. ................................................... 189 Ryskin A.I. ............................................................. 196 Sabsai O.Yu. ............................................................ 79 Safiulina A.M. ......................................................... 49 Sagun E.I. ................................................................. 93 Salazkin S.N. ..................................................... 45, 66 Samoilova R.I. ......................................................... 42 Samsonova L.G. ......................................... 23, 35, 133 Sariciftci N.S. ........................................................... 41 Sarkisov O.M. .................................................... 16, 38 Savelyev V.V. ................................................ 172, 189 Savelyeva A.V. ........................................ 19, 165, 192 Savvina L.P. ............................................................. 58 Sazhnikov V.A. .......................................... 43, 61, 170 Sazonov S.K. ........................................................... 43 Schoo H.F.M. ........................................................... 36 Selector S.L. ........................................................... 156 Selivanov N.I. .......................................................... 35 Seliverstova E.V. ..................................................... 57 Selkin A.V. ............................................................ 175 Semenishin N.N. .................................................... 101 Semenov A.Yu. ........................................................ 38 Sepashvili N. .......................................................... 135 Shabsels B.M. ........................................................ 198 Shakhverdov T.A. .................................................. 157 Shcheulin A.S. ....................................................... 196 Sheka E.F. ................................................ 37, 176, 197 Shelaev I.V. ............................................................. 38 Shelimov B.N. ....................................................... 144 Shelkovnikov V.V. ........................................ 193, 194 Shenderovich I.G. .......................................... 150, 151 Sheremetyeva N.V. ........................................ 154, 155 Sherstiuk V. ........................................................... 177 Shevchenko N.N. ............................. 43, 170, 175, 198 Shilova O.A. ............................................................ 75 Shiyonok A.I. ........................................................... 91 Shmyryeva A.N. ...................................................... 39 Shul’gin V.F. ........................................................... 23 Shulgin V.A. .......................................................... 114 Shumilkina E.A. ................................................. 33, 84 Shurygina M.P. ...................................................... 117 Shuvaev S.V. ........................................................... 85 Shvedova L.A. ....................................................... 158 Shvets V.I. ............................................................. 136 Simanchuk A.E. ..................................................... 194 Skubnevskaya G.I. ................................................... 40 Smagulov Zh.K. ....................................................... 58 Smirnov M.S. ........................................... 31, 111, 114 Smirnov N.N. ........................................................... 43 Smirnov V.A. ................................. 113, 141, 148, 162

Smirnova L.A. .......................................................... 15 Solodova T.A. .......................................................... 35 Soloveva E.V. .......................................................... 73 Solovjev V.S. ........................................................... 86 Solovskaya N.A. ...................................................... 43 Solovyov K.N. ....................................................... 137 Soulimenkov I.V. ..................................................... 60 Spirin M.G. ............................................................ 164 Spitsina N.G. ............................................................ 87 Starukhin A.N. ....................................................... 197 Stass D.V. ................................................................ 71 Strekal N.D. ........................................................... 178 Streltsov S.A. ......................................................... 201 Strikhanov M.N. .................................................... 182 Stroyuk A.L. .................................................... 83, 179 Stuchebrukhov A.A. .............................................. 105 Subbotina I.R. ........................................................ 103 Sultimova N.B. ...................................................... 159 Surin N.M. ................................................... 33, 77, 84 Susarova D.K. .................................................... 41, 88 Susarova S.D. ........................................................... 77 Suvalov V.A. ............................................................ 38 Suvorova T.I. ................................................. 111, 114 Sveklo I.F. ................................................................ 90 Sveshnikova E.B. ................................................... 180 Svetlichnyi V.A. .................................................... 128 Syl’yanov S.N. ....................................................... 183 Tameev A.R. .......................................................... 181 Tarasova N.A. ........................................................ 156 Tatikolov A.S. .................. 91, 118, 123, 158, 159, 160 Tedoradze M.G. ....................................................... 34 Telegina T.A. ......................................................... 119 Telminov E.N. ........................................................ 137 Tishchenko A.A. .................................................... 182 Titov V.V. .............................................................. 140 Tkachev V.V. ........................................................... 76 Tolochko A. ....................................................... 22, 63 Topilova Z.M. .......................................................... 23 Toporova Yu.A. ................................................. 17, 80 Tovstun S.A. .......................................................... 199 Troshin P.A. ..................... 41, 60, 77, 84, 88, 185, 197 Tsivadze A.Y. .......................................................... 49 Tsivadze A.Yu. .......................................... 50, 85, 172 Tsvetkov Yu.D. ........................................................ 42 Tsvirko M.P. .......................................................... 134 Tsyganenko A.A. ................... 116, 120, 149, 153, 163 Ukleev T.A. ............................................................ 175 Ushakov E.N. ................................................. 161, 166 Ushakova E.V. ............................................. 17, 19, 89 Usov N.N. ................................................................ 64 Utkina N.A. ............................................................ 130 Uzhinov B.M. .......................................................... 62 Van Heck G.T. ......................................................... 36 Vannikov A.V. ..................... 26, 69, 81, 172, 181, 189 Varfolomeev S.D. .......................................... 131, 136 Vasiliev V.P. .......................................................... 162 Vasilyuk G.T. ........................................................... 90 Vechtomova Yu.L. ................................................. 119 Vedernikov A.I. ............................................. 161, 166 Vershinnikova T.G................................................... 95 Volkov A.V. ............................................................. 86 Volkov V.V. ........................................................... 183 Voloshin N.A. .................................................... 51, 73

206

Von Borczyskowski C. ...................................... 44, 93 Vorobey A.V. ......................................................... 134 Voronina K.V. ....................................................... 163 Wieringa F.P. ........................................................... 36 Yakimansky A.V. .................................... 43, 170, 198 Yakushchenko I.K. .................................................. 67 Yarmoluk S.M. ...................................................... 123 Yudanova E.I. .................................................. 24, 200 Zabenkov I.V. ........................................................ 188 Zabolotskii A.A. .................................................... 195 Zaichenko N.L. ........................................................ 91

Zakharova I.B. ......................................................... 92 Zaporohzets M.A. .................................................. 183 Zaporozhets M.A. .................................................. 186 Zemtsov R.V. ................................................. 131, 136 Zenkevich E.I. .................................................... 44, 93 Zharkova G.M. ............................................... 184, 201 Zhigalina O.M. ....................................................... 183 Zhokhova D.A. ...................................................... 106 Zhuravlev N.A. ........................................................ 74 Zolotarevsky V.I. ................................................... 172 Zvezdin K.V. .......................................................... 136

207

LATELY RECEIVED ABSTRACTS

SURFACE PHOTOVOLTAGE AND BAND ALIGNMENT AT A HYBRID INTERFACE BETWEEN A CONJUGATED

ORGANIC OVERLAYER AND ZnO(0001) SURFACE

I.S. Busin, A.S. Komolov

Physics Department, St.Petersburg State University, Russia akomolov07@ya.ru

Formation of interfaces in hybrid materials made from a metal oxide and an organic semiconductor is usually accompanied by interfacial chemical reactions and this may be a route for making new functional surfaces. There are known efficient photovoltaic devices based on the interfaces between titanium dioxide and organic films [1,2]. The interface interaction could lead to formation of the interface related electronic states, which could be observed as additional peaks on the spectrum of the electronic structure of the organic films [3]. A few nm N,N-bis(3-methylphenyl)-N,N-bis(phenyl)-benzidine (TPD) overlayers were thermally deposited in situ in UHV onto ZnO (0001) surface. Atomic composition of the surfaces under study was monitored using Auger electron spectroscopy (AES). The formation of the interfacial potential barrier and of the structure of the unoccupied electronic states located 5-25 eV above the Fermi level (EF) were monitored using a probing beam of low-energy electrons according to the Total current electron spectroscopy (TCS) method. The spectroscopic results showed that the electronic density was transferred over the interface from the organic molecules to the ZnO (0001) surface. The electronic transfer was accompanied by the modification of the peak structure of the unoccupied density of states of the TPD film within a few nm thick layer. There was also found out that the surface potential of the TPD/ZnO hybrid structure was sensitive to visible light excitation. The major photovoltage response was observed within the excitation wavelength range from 360 nm to 600 nm, which corresponds to the quanta energies from 3.4 eV to 2 eV, approximately. The higher excitation energies within this range correspond to energy gap values for the TPD and ZnO materials under study. At the same time the photovoltage response at the excitation energies from 2 eV to 3 eV should correspond to the sub-bandgap energy transitions. These transitions involve the newly formed electronics states, which were formed upon formation of the hybrid ZnO/TPD interface. A formation mechanism for these electronic states considering the presence of the excess Zn atoms and the electronic dipole at the interface was suggested. The work was supported by RFFI grants 08-03-00270 и 09-03-12010.

References: [1] K.C. Kim, J.H. Park, O.O. Park, Solar Energy Materials and Solar Cells 92 (2008) 1188 [2] P. Suresh, P. Balaraju, S.K. Sharma, M.S. Roy, G.D. Sharma, Solar Energy Materials and Solar Cells.

92/8 (2008) 900. [3] Braun S., Osikowicz W., WangY., Salaneck W.R. Organic Electr. 8 (2007) 14. [4] Komolov A. S., Møller P. J., Mortensen J., Appl. Surf. Sci. 253 (2007) 7376

208

SENSITIZED LUMINESCENCE OF DOPED MOLECULAR ORGANIC POLYCRYSTALS

N.A. Klemesheva1, S.S. Nadoliskaya1, J.A. Rozhkova1, E.P.Zarochentseva1,

S.O.Vysotskaja1, D.A.Kudrjavtseva2, A.A.Evstrapov2, V.I. Korotkov1

1 – Physics Department, St.Petersburg State University, Russia 2 – Institute for Analytical Instrumentation RAS, St.Petersburg, Russia

korotkov@paloma.spbu.ru

Doped molecular polycrystals are good objects for investigating of phenomena of electronic excitation energy transfer owing to very close arrangement of host and quest molecules. Therefore it is possible two mechanisms of energy transfer – exchange-resonance and inductive- resonance. Earlier we detected appearance of long−lived states and sensitized phosphorescence in polycrystals of benzoic acid doped with bromated polyphenyls. The present work is concerned with the phenomena of heavy atom and crystal structure influence on sensitized luminescence of doped molecular polycrystals. Well known that heavy atoms increase the probability of the triplet yield caused by the spin-orbit coupling. At the same time, the introduction of heavy atoms into molecule almost does not change energy of the electronic levels of molecules. In crystals, because of the close packing of molecules, both - internal and intermolecular - heavy-atom effects are observed. To make clear influence of crystal structure on excited states properties of quest molecules in the doped molecular crystals we studied two host matrixes with different crystal structure and one quest molecule. Matrix molecules contain heavy atoms Br. The luminescent spectra of monobromated camphora (BC) and dibromobenzene (DBB) polycrystals doped anthranilic acid (ANTR ) have been investigated. Luminescence spectra of BC doped ANTR at room temperature consist of long-wave emission, attributed to phosphorescence. Spectrum is intensive and not resolved with one maximum at 450 nm. Changing of guest concentration leads to shift position of maximum. Concentration growth from 10-4 to 10-1 M/M moves maximum position from 420 nm to 440 nm. Phosphorescence excitation spectrum, detected at 425nm, has two maxima near 225 nm, and 365 nm. First band can be attributed to singlet-singlet absorption, second – to singlet-triplet (S0→T1) absorption. The excitation spectra, detected at different wavelengths indicate that short-wave and long-wave parts of phosphorescence spectrum have different excitation. The excitation spectra, detected at 470nm show band with maxima at 225, 350 and 405 nm. Under detecting at 440 nm long-wave maximum displaces to 380 nm, and under detecting at 425 nm maximum moves to 365 nm. There is a dependence of excitation spectrum versus guest concentration. Phosphorescence excitation spectra of polycrystals with different guest concentration show mixture of host (BC) and quest (ANTR ) absorption spectra. Part of quest absorption increase with increasing its concentration. Therefore one can concludes that luminescence spectra of BC doped ANTR at room temperature consist of superposition of host and quest molecules phosphorescence.

209

PHOSPHORESCENCE OF ORGANIC POLYCRYSTALS AT ROOM TEMPERATURE

N.A. Klemesheva1, S.S. Nadoliskaya1, J.A. Rozhkova1, E.P.Zarochentseva1,

S.O.Vysotskaja1, D.A.Kudrjavtseva2, A.A.Evstrapov2, V.I. Korotkov1

1 – Physics Department, St.Petersburg State University, Russia 2 – Institute for Analytical Instrumentation RAS, St.Petersburg, Russia

korotkov@paloma.spbu.ru

The objective of this work is to investigate the influence of heavy atom and crystal structure on the phosphorescence parameters and, in particular, the intersystem crossing rate constant. Since an approach to this topic requires analysis of a large quantity of experimental phosphorescence data 7 molecules were studied. To make clear influence of these factors on excited states properties of molecules the luminescent spectra of solutions and polycrystals of α-monobromated camphora (BC), acenaphthenequinone (ACNQ), acetanilide (ACTN ), dibromobenzene (DBB), mellitene (GMB ), triazole (TRZL ), anthranilic acid (ANTR ) has been investigated. Polycrystals of all investigated compounds exposed phosphorescence at room temperature. Phosphorescence of all compounds excites by singlet-singlet and forbidden singlet-triplet absorption. The main experimental parameters of the compounds studied are given. Phosphorescence spectrum of ACTN is well resolved, maximum situates at 416 nm. Phosphorescence excitation spectrum locates in spectral region 300-400 nm. ACNQ has maximum of phosphorescence at 470 nm. Maximum of phosphorescence excitation spectrum is situates near 355 nm. Phosphorescence spectrum of TRZL is unresolved with maximum at 425 nm. Phosphorescence excitation spectrum has two maxima: at 260 nm, corresponding to singlet- singlet (S0→S1) absorption and at 370 nm, corresponding to (S0→T1) absorption. ANTR exposes very intensive well resolved spectrum of phosphorescence with maximum at 450 nm. Broad phosphorescence excitation spectrum has two maxima near 320 nm, (S0→S1) absorption and 400 nm, (S0→T1) absorption. Phosphorescence spectrum of GMB has well resolved vibration structure, maximum situates at 470 nm. Phosphorescence excitation spectrum consists of two maxima near 220 nm, (S0→S1) absorption and 355 nm, (S0→T1) absorption. Low intensity phosphorescence spectrum of BC locates in broad spectral region 350-650 nm with maximum at 472 nm. Phosphorescence excitation spectrum has two parts: short-wave singlet- singlet absorption and long-wave singlet-triplet absorption. DBB polycrystals exhibit resolved phosphorescence in the 340-650nm region at room temperature. Spectrum has two maximums – 375 and 473 nm. Luminescence spectrum of DBB solution is unresolved and has fluorescence maximum near 310 nm and phosphorescence maximum at 470 nm. The excitation spectra, detected at different wavelengths indicate that short-wave and long-wave parts of phosphorescence spectrum have different excitation. The excitation spectra, detected at 375, 473 nm show well-resolved band corresponds to the singlet-triplet (S0→T1) absorption. There is a dependence of structural properties of DBB fluorescence excitation spectrum versus registration wavelength: the best resolution is observed at short-wave registration near 0-0 transition. The excitation spectra, detected at 500, 550 nm corresponds to the singlet- singlet (S0→S1) absorption. The crystals of DBB are monoclinic (a=15.36, b=5.75, c=4.10 A) and belong to space group P21/a(C2h

5) with two molecules per unit cell. Each allowed molecular state should, therefore, have two allowed components, one polarized parallel to and the other perpendicular to the b axis of crystal.

210

ELECTROLUMINESCENCE OF NONCONJUGATED POLYARYLENEPHTHALIDES

V.A. Antipin1, A.A. Kovalev2, A.N. Lachinov2, V.V. Shaposhnikova3,

S.N. Salazkin3, V.P. Kazakov1

1 - Institute of Organic Chemistry URC RAS, Ufa, Russia 2 - Institute of Physics of Molecules and Crystals URC RAS, Ufa, Russia

3 - Institute of Elementoorganic Chemistry RAS, Moscow, Russia lachinov@anrb.ru

Influence of the copolymer structure on the electroluminescence (EL) parameters has been investigated in this study. Copolymers, polyaryleneetherketones were tested. This copolymers are non-conjugated. However, if these copolymers have a phtalyde or dimethyl groups, these copolymers are able to conduct high current in film structure. That’s why the electric switching effect is observed in these polymers. The series of six polymers were studied. Polymers difference by content of the phtalyde and dimethyl groups (from 1% to 50%). EL measurements were carried out at the AL/polymer/ITO multilayer structure (ITO is a mixture of indium and tin oxides). The following parameters had been measured: the current-voltage characteristics, the photoluminescence spectrums, the excitation spectrum and the applied voltage dependence of the EL quantum efficiency. In state of comparison of the obtained results and previously published data studies with the polydiphenylenephtalide had been conducted. Dependences of the quantum efficiency on the percentage of the phtalide or phluorenon groups in the polymer chain are shown in fig. 1.

Fig. 1. Dependence of the quantum efficiency on the percentage of the phtalide or dimethyl groups in the copolymer polyaryleneetherketones. Excitation of the EL is at the direct (left) and

reverse (right) polarity.

The following features had been established during the investigation: 1. EL is observed in all series of the samples. 2. The quantum efficiently strongly depends on the chemical structure of the polymer, on

the phtalide group percentage particularly. 3. EL is observed with both polarity of the applied voltage. 4. Change of the EL spectrum is observed at the change of the polarity.

Quantum efficiency

Quantum efficiency

211

PHOTOPHYSICAL PROPERTIES OF HIGHLY LUMINESCENT PLATINUM 1,3,5-TRIAZAPENTADIENE COMPLEXES IN FLUID,

ADSORBED AND SOLID STATE

P.V. Gushchin1, N. Chakrova1, S.V. Litke1, G.N. Lyalin1, V.G. Maslov2

SPbSU 2 - SPbSU ITMO glialin@yandex.ru

Luminescent square-planar platinum(II) complexes have attracted a great attention due to their intriguing useful photophysical and photochemical properties. In this paper we report the results of study of two the most highly luminescent Pt-comlexes of the new family Platinum 1,3,5-Triazapentadiene complexes, the first synthesized in the Institute of Chemistry of SPbU1,2. [PtNH=C(Ph)-NC(Ph)=NPh2] (1) [PtNH=C(Ph)NC(NHPh)=NPh2] (2) The results of measurements of absorption, luminescence, excitatation of luminescence, lifetime of luminescence and luminescence quantum yield of complexes in solution, adsorbed on SiO2, in polystyrene matrix and in the solid state are summarized in the table.

Absorption ⋋/nm

(ε/M-1cm-1)

Excitation RT ⋋/nm

Emission RT ⋋em/nm,

ΦL

Degassed τ/µs,

Air-satureted τ/µs,

Degassed

complex matrix

1 2 1 2 1 2 1 2 1 2 1 2

CH2Cl2

241 256 293 415

315 380 400

293 320 415

315 380 400

535 540 0,004 0.007 0.01

Polylst.

298 330

298 330 427 450

335 380 426

526 555

491 523

0.4 1.85 3.4 (RT) 3.65 (77K)

1.83 0.81 (RT) 2.77 (77K)

Polycrst.

350 430 465

500 536

0.74 2.62 0.76 1.92 (RT)

0.76 1.92 (RT) 1.91 (77K)

SiO2

318 396 424

344 390 417

534 (RT) 548 (77K

527 0.3 0.4 1,6 (RT)

0.4 1.5 (RT)

0.7 2.0 (RT) 4.2 (77K)

0.4 1.6 (RT) 3.05 (77K)

To gain more insight into the above photophysical behavior, the electronic transition properties calculations of complexes were performed using time dependent density functional theory method (TDDFT) in the base of SBKJC. We studied also the luminescent properties of the complexes in different solvents such as dichloromethane, dibromomethane, nitromethane, acetonitrile, dimethyl sulfoxide. It was shown the typical quenching processes associated with e.g. solvent collision and formation contact complex (CT) between excited state of complex during it`s life time and solvent. 1. P. V. Gushchin, M. R. Tyan, N. A. Bokach, M. D. Revenco, M.Haukka, M-J. Wang, C-H. Lai,

P-T. Chou, and V. Yu. Kukushkin. Inorg. Chem., 2008, 47 (24), 11487-11500. 2. .H.Sarova, N.A.Bokach, A.A.Fedorov, M.N.Berberan-Santos, V.Y.Kukushkin, M.Haukka,

J.R.Frausto da Silva, A.J.Pombeiro. Dalton Trans., 2006,3798-3805.

212

INTRAMOLECULAR EXCITATION ENERGY TRANSFER IN Zn OCTACARBOXYPHTHALOCYANINE TETRACONJUGATE

WITH RHODAMINE C

D.A. Makarov, L.P. Savvina, L.I. Solovyova, L.E. Marinina, N.A. Kuznetsova, O.L. Kaliya, E.A. Lukyanets

Institute of Organic Intermediates and Dyes, Moscow, Russia

jerrik@rol.ru

Tetraconjugate of octacarboxysubstituted zinc phthalocyanine (OCZnPc) with Rhodamine C (RhC) (conjugate) has been synthesized. The absorption spectrum of conjugate in visible region has rhodamine and phthalocyanine bands (in DMSO at 565 nm and 703 nm accordingly). Intramolecular excitation energy transfer in conjugate from rhodamine to phthalocyanine part has been investigated by fluorescence and singlet oxygen generation studies. The energy transfer in conjugate in DMSO results in quenching of the donor (rhodamine) fluorescence and appearance of the acceptor (phthalocyanine) fluorescence at excitation of the rhodamine part.

The singlet oxygen quantum yields (Φ∆) studies in DMSO have confirmed intramolecular excited energy transfer from rhodamine to phthalocyanine part in this molecular system. Thus, RhC alone has negligible ability to sensitize 1O2 formation (the quantum yield Φ∆ for RhC is < 0.01). However, under excitation of RhC, conjugated with OCZnPc, formation of 1O2 with rather high quantum yield of 0.25 was observed. This finding clearly indicates energy transfer from rhodamine residues to 1O2 generating phthalocyanine part of conjugate. It can be noticed that Φ∆ values for conjugate both under selective excitation of rhodamine or phthalocyanine chromophores are equal to 0.25, that is substantially, about three times lower than Φ∆=0.70 for unbounded OCZnPc. It was found that the fluorescence and singlet oxygen quantum yields for conjugate are smaller than for unbounded dyes. This finding suggests appearance in conjugate of competitive charge-transfer-mediated process of excitation energy dissipation.

N

N

N

N

N

N

N

N

Zn

C

C

CC

C

C

C C

O

O

OO

O

O

O

O

NR

NR

RN

RN

R=

Cl

O

O NN

CCH2CH2O

H5C2

H5C2

C2H5

C2H5

213

NONLINEAR OPTICAL PROPERTIES OF FULLERENE-DOPED ORGANIC STRUCTURES

A.I. Plekhanov1, N.V. Kamanina2, A.E. Simanchuk1

1 – Institute of Automation and Electrometry SB RAS, Novosibirsk, Russia

2 – S.I. Vavilov State Optical Institute, St.Petersburg, Russia fractal@iae.nsk.su

Fullerene-doped conjugated organic structures offer a special interest among a wide

variety of nanostructures. Such structures possess a high nonlinear optical response. In this work the number of film-like samples was investigated: both the pure fullerene samples and the fullerene-doped π-conjugated organic structures [1,2].

The thickness of the films varied from 0.5 to 2 mkm. We have studied the nonlinear optical response of thin films by z-scan method and four-photon mixture at nanosecond and picoseconds excitation at the wavelength of 532 nm. The obtained data are compared with the nonlinear optical properties of other materials known from the literature [1-9].

From the comparison follows that the nonlinear optical parameters of fulleren-doped polymer nanostructures are larger than those obtained for traditional nonlinear systems that permit to apply these materials as effective holographic recording element, spatial light modulator, switchers, nonlinear absorber in the visible and in the near-infrared spectral ranges. Moreover, the data testify that nonlinear characteristics of the materials studied are close to the Si-based structures that provoke the organics structures with nanoobjects to be used in organic solar energy technique. [1] Kamanina, N. V. Optics and Spectroscopy, 90, 867 (2001). [2] Kamanina, N. V. Synthetic Metals, 139, 547 (2003). [3] Liu Huimin, Taheri B., Weiyi Jia, Phys. Rev., B49, 10166 (1994). [4] Kaizar, F., Taliani, C., Muccini, M., Zamboni, R., Rossini, S., Danieli, R. Proceed. SPIE,

2284, 58 (1994). [5] Li, J., Feng, J., Sun, J. J. Chem.Phys., 203, 560 (1993). [6] Krätschmer, W., Lamb, L. D., Fostiropoulos, K., Huffman, D. R. Nature, 347, 354 (1990). [7] McBranch, D. W., Maniloff, E. S., Vacar, D., Heeger, A. J. Proceed. SPIE, 3142, 161 (1997). [8] Ganeev, R. A., Ryasnyansky, A. I., Kodirov, M. K., Usmanov, T. Opt. Commun., 185, 473

(2000). [9] Kamanina, N. V., Sheka, E. F. Opt. Spectrosc., 96, 599 (2004).

214

FTIR STUDY OF OZONOLYSIS AND PHOTOOXIDATION OF ADSORBED CHLOROETHENES

A.A. Tsyganenko, N.V. Zakharov, N.M. Tsyganenko

V.A. Fock Institute of Physics, St.Petersburg State University, Russia

tsyg@photonics.phys.spbu.ru

Surface chemistry of halogenated hydrocarbons attracts much attention in the recent years due to their role in stratospheric ozone destruction. The aim of this work was to study surface reactions of chloroethenes with ozone at 77-293 K on two different oxides, which could be considered as model aerosols: relatively inert SiO2 and catalytically active TiO2. To see the effect of adsorbed H2O, experiments with TiO2 were carried out at different stages of surface dehydration. FTIR spectra of all chlorinated ethenes (C2H3Cl, trans, cis and gem isomers of C2H2Cl2, C2HCl3 and C2Cl4) adsorbed on TiO2 and SiO2 reveal only molecular adsorption at temperatures below ambient. For monochloroethene, ozone admission, besides the bands of adsorbed ozone1,2, results in the appearance of new bands of products already at 77 K in the spectra of the studied samples. Adsorbed di-, three- and tetrachloroethene are less reactive towards ozone and either react at higher temperature (cis and trans-dichloroethenes) or do not display formation of products at all (C2HCl3 and C2Cl4 on silica). TiO2 exhibit higher activity towards ozonolysis of chloroethenes. For all the adsorbates weak bands of products start to grow in the spectra of titania already at 77 K. Preliminary water adsorption decreases the activity of TiO2, delaying the starting temperature of reaction up to 100- 140 K. Among the first products of ozonolysis, formaldehyde (bands at about 1720 and 1500 cm-1), phosgene (1805 cm-1) and formylchloryde HClCO were identified, as well as the bands assignable to primary or secondary ozonides, while at the final stage water, CO2 and surface carboxylate-like species appear. The mechanism of reaction is consistent with Criegee’s scheme, as in the case of ozone interaction with ethene adsorbed on silica3. Degradation of chlorinated hydrocarbons in atmosphere can be stimulated by UV irradiation. To reproduce this effect we have studied the changes in the spectra of gem-dichloroethene adsorbed on TiO2 in the presence of oxygen under irradiation by undecomposed light of mercury lamp in the quarts tube at 300 K. Decrease of the bands of adsorbed molecules as well as the appearance of new bands of photoproducts testify for the dichloroethene photooxidation, although the final spectrum was different from that after ozonolysis. No photooxidation was detected on silica, but irradiation at 77 K in the presence of ozone leads to oxidation of dichloroethenes even on inert surfaces, such as silica or disperse ice4, apparently, due to photoactivation of ozone molecules by UV light.

Acknowledgement. The authors acknowledge with thanks the support of this work by grants INTAS 03-51-5698, RFFI 06-03-32836a and RFFI 06-05-64646a.

References: 1. Bulanin K.M., Alexeev A.V., Bystrov D.S., Lavalley J.-C., Tsyganenko A.A. J. Phys. Chem., 98

(1994), 5100. 2. Bulanin K.M., Lavalley J.-C., Tsyganenko A.A. J. Phys.Chem. 99 (1995), 10294. 3. Manoilova O.V., Lavalley J.-C., Tsyganenko N.M., Tsyganenko A.A. Langmuir, 14 (1998), 5813. 4. A.V. Rudakova, V.N. Sekushin, I.L. Marinov, A.A. Tsyganenko. Molecules in Space and Laboratory.

Proc. Int. Conf. Paris, France, 2007.