Book of Abstracts -...

International School on Fundamental Crystallography followed by a one-day Workshop on Representation Theory of Space Groups

November 29 – December 4, 2010 Facultad de Química, Universidad de la República, Montevideo, Uruguay

http://cryssmat.fq.edu.uy/ISFC2010

Book of Abstracts

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International Program Committee

Prof. Massimo Nespolo, (Universite Nancy, France)

Prof. Ernesto Estevez-Rams, (Universidad de La Habana, Cuba)

Prof. Mois I. Aroyo, (Universidad del País Vasco, España)

Prof. Leopoldo Suescun, (Universidad de la República, Uruguay)

Prof. Gustavo Echeverria, (Universidad Nacional de La Plata, Argentina)

Prof. Eduardo Granado, (Universidade Estadual de Campinas, Brasil)

Preparatory Session:

Prof. Ricardo Faccio (Universidad de la República, Uruguay)

Prof. Leopoldo Suescun (Universidad de la República, Uruguay)

Workshop:

Prof. Mois I. Aroyo (Universidad del País Vasco, Espana)

Local Organizing Committee

Universidad de la República – Facultad de Química

Dr. Leopoldo Suescun, Chair, [email protected]

Dr. Ricardo Faccio, [email protected]

Dr. Álvaro W. Mombrú, [email protected]

Dr. Helena Pardo, [email protected]

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Sponsors

Facultad de Química, Universidad de la Republica, Montevideo, Uruguay

Centro Interdisciplinario de Nanomatecnología y Química y Física de Materiales, Universidad de la

República, Uruguay

Agencia Nacional de Investigación e Innovación, Uruguay

International Center for Diffraction Data

International Union of Crystallography, Commission on Mathematical and Theoretical Crystallography

PEDECIBA, Programa para el Desarrollo de las Ciencias Básicas, Uruguay

Comisión Sectorial de Investigación Científica, Universidad de la República, Uruguay

American Crystallographic Association

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International School on Fundamental Crystallography – Detailed Program.

Monday

8:30 - 8:50 Registration

8:50 - 9:00 Opening Ceremony

M.S. 1 Crystallographic symmetry and periodicity

M.S.2 Lattices in 2 and 3 dimensions

A.S. 1 Point groups and stereographic projection

A.S. 2 Matrix algebra of point groups

19:00-20:00 Wellcome Reception

Tuesday Poster session start

M.S. 1 Introduction to space groups

M.S.2 Exercises on space groups

A.S. 1 Exercises on space groups

A.S. 2 Crystallographic point groups: group-subgroup relations; generation of point groups

Wednesday Posters

M.S. 1 Space-group symmetry data in International Tables for Crystallography, Vol. A

M.S.2 Exercises

A.S. 1 Group-subgroup relations of space groups

A.S. 2 Exercises

Thursday Posters

M.S. 1 The Physics of Diffraction, Reciprocal space as Fourier transform of direct space. Convolution.

M.S.2

Crystallographic calculations in reciprocal space. Diffraction symmetry: Laue classes, Friedel laws,

resonant scattering.

A.S. 1 Integral, zonal and serial reflection conditions and their use to determine the space-group type.

A.S. 2 Example of structure determination and refinement using SHELX

19:00-21:00 Farewell cocktail

Friday Poster session ends

M.S. 1 Crystallographic databases and access tools

M.S.2 Group-subgroup relations between space groups

A.S. 1 Structure utilities and tools

A.S. 2 Structural pseudosymmetry

18:00 -18:30 Closing Ceremony, Poster prizes announcement, Certificates give-away.

Workshop: Representation Theory of Space Groups

Saturday

M.S. 1 Representations of crystallographic groups: general introduction

M.S.2 Representations of crystallographic point groups

A.S. 1 Representations of space groups

A.S. 2

Databases and tools of representations of crystallographic groups on the Bilbao Crystallographic

server

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ABSTRACTS

8

In-situ structural characterization of nano-sized scandia-doped zirconia.

Fernández-Werner L.1, Suescun, L.1, Abdala, P. M.2, Lamas, D. G.2, Chen, H.3 and Craievich AF4

1 Universidad de la República - Montevideo Uruguay

2 Consejo Nacional de Investigaciones Científicas y Técnicas - Buenos Aires Argentina

3 Brookhaven National Laboratory - Upton NY United States of America

4 Universidade de Sao Paulo - Sao Paulo - Sao Paulo SP Brazil

Oxides with Fluorite structure doped with trivalent cations such as Zr1-xMIII

xO2-x/2 and Ce1-xMIII

xO2-x/2 are currently the most adequate materials for high and intermediate temperature Solid Oxide Fuel Cells (SOFC) electrolytes respectively.

Particularly, ZrO2-Sc2O3 electrolytes are widely investigated because they exhibit the highest ionic conductivity among all ZrO2-based materials. The main problem of the use of these ceramics is to avoid the presence of the low-conductivity monoclinic and rhombohedral phases. This is generally achieved by adding a second dopant that stabilizes the cubic phase being Y2O3 or CeO2 the most used, but reducing ionic conductivity. ZrO2 - Sc2O3 ceramics exhibit different polymorphs depending on the composition and temperature, with monoclinic, tetragonal, cubic or rhombohedral symmetries. Yashima and coworkers constructed a metastable phase diagram for compositionally homogeneous materials ZrO2 - Sc2O3 synthesized at high-temperatures. In ZrO2-based systems, the tetragonal phase can exhibit three metastable forms: t, t' and t" forms. The stable tetragonal form is called the t-form. The t'-form has a wider solubility, but is unstable in comparison with the mixture of the t-form and cubic phase. The t"-form has an axial ratio, c/a, of unity with the oxygen atoms displaced along the c axis from their ideal sites of the cubic phase. In the ZrO2 - Sc2O3 system. In recent studies, Abdala et al. showed that the t"-form can be retained in nanopowders for Sc2O3 contents close to 10 mol% if the crystallite size is smaller than 25-30 nm and proposed a metastable phase diagram for these nanomaterials. In this way, the β-phase can be avoided without the incorporation of additional dopants. In this presentation we will show the latest results obtained from an in-situ characterization of nanosized powders of

ZrO2 - Sc2O3 (10%) performed at Brookaven National Laboratory's NSLS (X7B station) to precisely determine phases present at different temperatures and grain sizes in order to avoid the formation of undesired phases upon processing of material for applications.

Acknowledgements: The authors are indebted with Dr. Jonathan Hanson from X7B sta-

tion at NSLS-BNL for providing beam time.

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Molecular and Electronic Structure of the Gedulina C28H34O6

P. S. Carvalho Júnior, V. H. C. Silva, H. B. Napolitano & A. J. Camargo

Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás, Goiás, Brazil.

The gedulina compound C28H34O6 is a natural product extracted from Brazilian plants and has shown inhibitory activity

against Leishmania Major. The compound is a derivative of terpoids and shows the acetone and ether functional groups

as most susceptible to reactions The substance crystallizes in the Orthorhombic crystal system (a = 14.8348 Å, b =17.0079

Å, c = 19.8473 Å), space group P212121, V = 5007.65 A3 and Z = 8. The crystallographic structure was determined by

Direct Method and refined to R = 0.0638 and S = 1.1260. There are two independent molecules in the asymmetric unit

and their electronic structures were investigated within Density Functional Theory with the 6-311++(d,g) basis set. Both

conformers show structural identity throughout whole molecule except for the ether cyclopentane, as shown on Figure 1.

The conformational change feature energetic barrier is about 11.88 kcal/mol. The energy difference between these two

states does not change significantly and show charge electronic redistributions for rotated group without modification for

oxygen atom. This is related to the difference between the two molecules. The similarity and complementarily of loads of

conformers provide requisites for the stability of system.

Acknowledgement:

UEG, CAPES

O

O

O

O

O

O

O

O

O

O

O

OO

Figure 1: Conformers of Gedulina compound

10

Syntheses and Structural Analysis of ‘retinoid-like chalcone’ C20H22NO2

William B. Fernandesa, Caridad Noda Pereza, Hamilton B. Napolitanoa.

Department of Chemistry, UnUCET, State University of Goias, Anapolis, Brazil.

E-mail adress: [email protected]

Chalcones are considered precursors of the biosynthesis of flavonoids and are obtained by condensation reaction of Claisen-Schmidt between a ketone and an aromatic aldehyde in the presence of basic catalysts. The importance of chalcones is based upon the wide variety of chemical and biological properties presented by them. Furthermore, chalcones have been the subject of several theoretical and experimental studies that aimed their crystallographic molecular structures, chemical reactivity, antimicrobial activity, among other applications in the therapy field[1,2]. In order to develop new drugs the analogue of chalcone of retinoid type (1E,4E)-1-(4-nitrophenyl)-5-(2,6,6-trimetilciclohex-1-enyl)-penta-1,4-dien-3-one was obtained from the equimolar coupling of the β-ionona with p-nitrobenzaldeide by classical Claisen-Schimidt condensation using lithium hydroxide as catalyst. The compound was isolated by liquid-liquid extraction using dichloromethane, and precipitated with ethanol and then filtered. The single crystal was obtained by indirect diffusion technique using a system of hexane and methanol. The structure was solved by Direct Methods and refined by full matrix Least Square method on F2 using WINGX package[3]. Non H atoms were refined anisotropically and all H atoms were placed geometrically. The compound crystallizes in the P21/c monoclinic space group and the cell dimensions are: a = 11.594(2) Å, b = 11.715(2) Å, c = 14.202(2) Å, α = γ = 90° and β = 110.147(5)°; Z = 4 and V = 1810.8(4) Å³. 17572 measured reflections with 3211 unique and 2166 observed [I > 4σ(I)]. The final residual R1 factor is 0.0525 for 278 refined parameters. One non-classical intra-molecular hydrogen bond C–H...O [2.856(3) Å] stabilizes the molecule in partially planar arrangement. The nature of the observed static disorder was investigated theoretically within Density Functional Theory. The transition state structure was obtained and the calculated potential barrier energy is 0,10 kcal/mol. The effect of crystal packing was also examined. This work was financed by CAPES (process 2036-09-6) and PrP/UEG. [1] Dominguez J, Charris J, (2001) European Journal of Medicinal Chemistry 36: 555 – 560. [2] Valla A, Valla B, Cartier D, et al. (2006). European Journal of Medicinal Chemistry, 41: 142 - 146. [3] Farrugia, L. J. (1999). Journal Appl. Cryst., 32: 837 - 838.

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Synthesis and structural analysis of ethyl (2E)-3-(4-hydroxy-3,5-dimethoxyphenyl)prop-2-enoate

Jefferson L. F. Silva¹, Lorraine A. Malaspina², Carlito Lariucci², William B. Fernandes¹, Hamilton B. Napolitano¹, Gilberto L. B. Aquino¹

¹Department of Chemistry, UnUCET, State University of Goias, Anapolis, Brazil.

²Department of Physics, Federal University of Goias, Goiânia, Brazil It is assumed that the dihydrocoumarin have biological activity front of Alzheimer's Disease (AD) and other diseases which justifies its study. It was verified by (Li, 2005)[1] that the Hidroarilation of Olefins catalyzed by Trifluoroacetic Acid (TFA) results in molecules of dihydrocoumarin with good yields. From this reasoning were performed various reactions of Wittig, obtaining as product, compounds α, β-Unsaturated that by turn were used to react by condensation with Phenols forming as product the dihydrocoumarin. One of the compounds α, β- Unsaturated obtained, the ethyl (2E)-3-(4-hydroxy-3,5-dimethoxyphenyl)prop-2-enoate, drew attention for forming been a well-defined crystals. This compound was obtained from the reaction between Etoxycarbonylmetilene (triphenyl) phosphorane (ylide of Phosphorus) and 4-Hydroxy-3,5-dimetoxifenil-Benzaldehyde. The compound was isolated by flash Cromatography, using a glass column appropriate diameter and silica gel flash as phase stationary (230-400 mesh, 60 Å). The single crystal was obtained by indirect diffusion technique using a system of hexane and methanol. The structure was solved by Direct Methods and refined by full matrix Least Square methods on F2 using WINGX package[3]. Non H atoms were refined anisotropically and all H atoms were placed geometrically. The compound crystallizes in the C2/c monoclinic space group and the cell dimensions are: a = 21.273(1) Å, b = 7.391(1) Å, c = 17.898(1) Å, α = γ = 90° and β = 92.640(1)°; Z = 8 and V = 2811.0(1) Å³. 23908 measured reflections with 4279 unique and 2848 observed [I > 4σ(I)]. The final residual factor R1 is 0.0479 for 181 refined parameters using 0 restraints.

Acknowledgements: This work was partially financed by CAPES and FUNAPE/UFG. The Data Collection were done by Prof. Robert Burrow at the Chemistry Department of UFSM.

[1] Li, K.; Foresse, N. L.; Tunge, J. A. (2005) Journal of Organic Chemistry, 70, n° 7. [2] Barreto, R. A. (2003) Design e síntese de novos análogos estruturais da acetilcolina [Dissertação]. Unicamp, Campinas-SP. [3] Farrugia, L. J. (1999). Journal Appl. Cryst, 32: 837-838.

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Crystal structure analyses of novel tin complexes with dithiocarbimate derivated of sulfonamides

Rosane P. Castro1, Jose Ricardo Sabino1, Marcelo R. L. Oliveira2, Liany D. L. Miranda2,

Mayura M. M. Rubinger2.

1Instituto de Física, Universidade Federal de Goiás, Goiânia GO, CEP 74001-970, Brazil.

2Departamento de Química, Universidade Federal de Viçosa, Viçosa MG, CEP 36571-000, Brazil.

Several dithiocarbamates complexes and anions exhibiting biological activity are used as fungicides and

pesticides due to their efficiency in controlling plant fungal diseases and relatively low toxicity [1]. Besides they are

poorly studied, the interest in the characterization of metal complexes of dithiocarbimates is due to their similarities with

dithiocarbamates compounds. Moreover, some sulfonamide derivatives have also shown biological activity being

fungicides and anticancer agents. The dithiocarbimates are, necessarily, anionic species. So the applications of these

complexes also depend on the choice of the counter ion [2]. In this work we present the x-ray single crystal structure

analyses of two new complexes of tin dithiocarbimates from sulfonamides: (Ph4P)2[SnMe2(PhClSO2N=CS2)2] and

(Ph4P)2[SnMe2(PhNSO2N=CS2)2]. These two complexes were obtained by adding dimethyltin dichloride (0.7 mmol) to a

solution of the appropriated potassium N-R-sulfonyldithiocarbimate dihydrate (1.5 mmol) in water (10 mL). The mixture

was stirred for 30 minutes at room temperature. Tetraphenylphosphonium chloride (1.5 mmol) was added to the solution

obtained. The mixture was stirred for 15 minutes and the obtained white solid produced was filtered, washed with distilled

water and dried under reduced pressure for three days, yielding (Ph4P)2[SnMe2(RSO2N=CS2)2] (ca. 70%). Suitable

colourless crystals for X-ray structure analysis were obtained after slow evaporation of the solutions of the compounds in

acetone/water 3/1. In both compounds the asymmetric unit consists of two chemical equivalents but crystallograpically

independent ligands coordinated to the Sn atom, and two tetraphenylphosphonium cations. The tin atom is coordinated by

two sulfur atoms and by two methyl. The structures were solved and refined using the WinGX package[3]. Both

compounds crystallize in the orthorhombic space group Pbca. In the crystal packing of the two compounds there are weak

interactions of types C─H·····X (X = O, N or S) and N─H·····N. The final indexes for (Ph4P)2[SnMe2(PhClSO2N=CS2)2]

were wR2 = 0.1076, R1 = 0.0455 and for (Ph4P)2[SnMe2(PhNSO2N=CS2)2] were wR2 = 0.1084, R1 = 0.0393.

[1] D.C. Menezes, F.T.Vieira, G.M. de Lima, A.O. Porto, M.E. Cortés, J.D. Ardisson, T.E. Albrecht-Schmitt,

European Journal of Medicinal Chemistry 40 (2005) 1277–1282

[2] R. S. Amim, et al., Syntheses, crystal structure and spectroscopic characterization of new platinum(II) dithiocarbimate

complexes, Polyhedron 27 (2008) 1891-1897.

[3] L.J. Farrugia, J. Appl. Cryst., 1999, 32, 837-838.

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Crystallographic Study on Phase Stability of Tetragonal Zirconia Powders Obtain by Chemical Methods: Microstructural evolution study by XRD-FTIR relatio nship

D. A. Campo Ceballos University of Brasilia, Facultade de Tecnología. Campus Darcy Ribeiro, [email protected]

Brasília - CEP 70910-900 - Telefone (55 61)3107-3300 J. E Rodriguez Páez

University of Cauca, Department of Physics. Calle 5 Nº 4 –70, Popayan, Cauca, Colombia. [email protected]/Fax (+57)(2) 8209800 Ext 2410

Zirconium oxide (ZrO2) is an extremely versatile ceramic that has found use in different applications, for example, in high toughness applications. Research on this material actively continues and the interest and usefulness of zirconia can be seen from the voluminous literature found on this material and it has applications making use of its electrical, thermal, and mechanical properties. Zirconium oxide has three crystalline phases: The thermodynamically stable room temperature form of zirconia is monoclinic, as mineral called “baddeleyite”. Tetragonal phase, stable until 2370 ºC, it has good mechanical properties. Cubic phase, stable until 2650 ºC, it has high ionic conductivity values at high temperature. Zirconia is use in mixtures to improve the mechanical properties of industrial materials. In addition, their high melting point, 2650 ºC, makes it able to manufacture tools for foundry, and as a biocompatible and resistant material allow manufacturing dental and knee and hip protesis. By the addition of significant amounts of dopants, for example CaO, tetragonal or cubic phase can be stabilized at room temperature.

In this work tetragonal ZrO2-doped CaO powders, were obtained by the polymeric precursor method and controlled precipitation method. Synthesis conditions and thermal treatments have been considered to study powder microstructure. The samples were characterized using Fast Fourier Infrared Spectroscopy (FTIR), X-Ray powder diffraction (XRD) and structural Rietveld Refinement. The evolution of the crystallographic structure of doped-ZrO2 powders after air annealing at various temperatures 600ºC, 800ºC and 1000ºC was studied to well understand the conditions of the formation of desired metastable tetragonal phase and the relationship with vibrational properties of zirconia powders.

14

Magnetic and EPR study of the complex Co(II)Fumarato

Nicolás Neuman,1 Elín Winkler,2 Octavio Peña,3 Mario Passeggi,1,4 Alberto Rizzi1 y Carlos Brondino1

1Departamento de Física, FBCB, UNL, Santa Fe, Santa Fe

2Instituto Balseiro, Centro Atómico Bariloche, CNEA, S.C. de Bariloche, Río Negro

3Sciences Chimiques de Rennes, UMR 6226, Université de Rennes 1, France

4INTEC, CONICET, Güemes 3450, Santa Fe, Santa Fe [email protected]

Introduction: Cobalt(II) ions are found in several metalloproteins and are often used as spectroscopic probes of active sites, replacing metal ions such as Zn(II), because their magnetic properties are very sensitive to coordination geometries and ligand types. High spin Co(II) ions (S = 3/2) in distorted octahedral sites present magnetic anisotropy arising from zero field splitting (ZFS) of its spin energy levels.1-3 Magnetization and Magnetic Susceptibility results can be analyzed by use of a spin Hamiltonian in the S = 3/2 base. In an Electron Paramagnetic Resonance (EPR) experiment, because the ZFS term is usually much larger than the microwave energy, the results can be analyzed by means of an effective spin Hamiltonian in a S´ = 1/2 base.

Objectives: • To study the magnetic properties of a cobalt(II)-carboxylate coordination compound: Co(II)(Fumarato)(H2O)4,

which crystallizes in the monoclinic (P21/c) group, by EPR spectroscopy, Temperature-dependent Magnetic Susceptibility (χ) and Field-dependent Magnetization (M).

• To obtain the crystal and molecular g-tensors and ZFS parameters D and E. • To relate magnetic and EPR results.

Results: Single crystal EPR spectra of Co(II)Fumarato were taken at 9.5 GHz and 4 K for multiple orientations of the magnetic field B in an orthogonal abc* coordinate axis (c* = a × b). Least squares fitting of the resonance lines afforded the effective g-factor for each orientation. The crystal g2-tensor was calculated from the angular dependence of g2. Its eigenvalues were g1

2 = 26.30 g22 = 14.16 g3

2 = 16.82. Magnetization and Magnetic Susceptibility results were least squares fit to a model based on a Spin Hamiltonian in a S = 3/2 base, including Zeeman, ZFS and molecular field terms. The last term accounts for magnetic exchange between neighboring cobalt(II) ions. The magnitude of the fitting parameters g, D and E were consistent with those expected for a cobalt(II) ion in a distorted octahedral environment. The effective molecular g-tensor parameters (in the S´= 1/2 base) were determined from the crystal g-tensor and were related to the g, D and E parameters obtained from magnetic measurements using an appropriate model.4,5

References

1. Rizzi et al., Inorg. Chem, 2003, 42, 4409-4416 2. Larrabee et al., J. Am. Chem Soc., 1997, 119 (18), 4182-4196 3. Kahn, O., Molecular Magnetism, 1993, New York, USA: VCH Publishers. 4. Werth et al., Inorg. Chem., 1995,34, 218-228 5. Pilbrow, J. R., J. Magn. Reson., 1978, 31, 479-489

Acknowledgements

Work funded by CONICET, CAI+D UNL and ANPCyT (Project N° 00439 PICT 2006 BID 1728 OC/AR and Project N°06 13872 PICT 2003 BID 1728 OC/AR)

17

Synthesis, X-Ray structures, spectroscopic properties of ruthenium(II) complexes with phosphines and diimines and dithiocarbimates derived from sulfonamides

Joao P. Barolli 1, Javier Ellena2, Alzir A. Batista1

1 Departamento de Química, Universidade Federal de São Carlos, UFSCar, Rodovia Washington Luiz, KM 235 CP 676, CEP 13561-901, São Carlos–SP, Brazil. 2 Departamento de Física e Informática, Instituto de Física de São Carlos, Universidade de São Paulo, USP, CP 369, CEP 13560-970, São Carlos–SP, Brazil.

Ruthenium complexes have attracted interests due to their importance as antitumor agents. Many compounds containing phosphines and other ligands exhibit cytotoxic activity against tumor cells line MDA-MB-231[1]. A strategy to improve the biologic activity may be employing other kind of ligands. Here, we have used dithiocarbimate derivatives as an alternative. Dithiocarbimates and their metal complexes are poorly studied[2]. Therefore, we are interested in the syntheses and characterization of two complexes of ruthenium(II) with dithiocarbimates from sulfonamides [Ru(dppb)(bpy)(RSO2NCS2)] where dppb=1,4-bisdiphenilphosphinobutane, bpy=2,2’-bipyridine and R= C2H5 (1), 4-Cl-C6H4 (2). The 31P{1H} NMR spectra of 1 and 2 in CDCl3 presented a typical AX spin systems with chemical shifts at 46.5 (d); 34.3 (d) and 47.3 (d); 33.6 (d) ppm, respectively, with 2JP-P = 27.0 Hz, indicating the magnetic nonequivalence of the two phosphorus atoms. Table 1. Spectroscopic data ruthenium complexes.

νCN νCS2 31P{1H} (ppm) P-Ru-P (º) Ru-S1 (Å) Ru-S2 (Å) C=N (Å)

1 1383 (F) 942 (M) 46.5 ; 34.3 94.68(8) 2.378(2) 2.442(2) 1.34(1)

2 1377 (F) 939 (M) 47.3 ; 33.6 95.65(5) 2.374(1) 2.446(1) 1.321(6)

The recrystallization of 1 and 2 were performed by slow evaporation of ethanol/dichloromethane solution. X-ray data of crystals were measured on an Enraf-Nonius Kappa-CCD diffractometer with graphite monochromated MoKα (0.71073 Å) radiation. The structures were solved by direct methods with SHELXS-97 and refined by full-matrix least-squares on F2 using SHELXL-97. The complexes 1 and 2 crystallize in the centrosymmetric C2/c and P21/n space groups, respectively. The P–Ru–P angle in the seven-membered ring of dppb is around 95º, comparable with the values previously observed[3]. The most interesting aspect involves the coordination of the NCS2 moiety to the ruthenium atom. Concerning Ru—S bond lengths, it is observed different values due to the trans effect exerted by the phosphorus atoms. The C═N bond distances have a double character, confirming that the electron density is delocalized over the entire NCS2 moiety. In both crystal structures (a and b) were observed non-classical hydrogen bonds involving the sulfonamide group, such as illustrated in Figure 1c. Also, van der Waals and π-π stacking interactions stabilize the crystal packing.

Figure 1. Molecular structure of the compound 1 (a) and 2 (b). The H-Bond patterns of 1 and 2 (c). The H atoms were omitted.

1 Graminha, A. E., et al. Spectrochimica. Acta, Part A 69 (2007) 1073. 2 Alves, L. C., et al. Journal of Inorganic Biochemistry 103 (2009) 1045. 3 Queiroz, S. L. et al., Inorganic Chimica Acta 267 (1998) 209–221.

28

A primary review of the synthesis and characterization by XRD of the new high Tc superconductor of the YBCO family; Y 3Ba5Cu8O18 (Y358).

Mariano Romero, Helena Pardo, Ricardo Faccio, Álvaro W. Mombrú.

Crystallography, Solid State and Materials Laboratory (Cryssmat-Lab), DETEMA, Facultad de Química, Universidad de la República, Gral. Flores 2124, P.O. Box 1157, Montevideo, URUGUAY

Centro NanoMat, Polo Tecnológico de Pando, Facultad de Química, Universidad de la República, Cno. Aparicio Saravia s/n, 91000, Pando, Canelones, URUGUAY.

Abstract

Recently Akhavan et al. have reported the synthesis, structural characterization [2] and electronic structure simulations [1] of a new high Tc (107º K) superconductor of the YBCO family; Y3Ba5Cu8O18 (Y358).

In this work we present several studies, in order to improve the synthesis of the Y358 ceramic, accompanied by an X Ray Diffraction (XRD) study for the structural characterization.

The original solid-state synthesis [2] was modified, utilizing different reactants under different atmospheres. Additionally, the sol-gel technique was employed in order to evaluate differences with the ceramic method.

The crystal structure refinements have been done using full pattern refinement by means of the Rietveld method [3] and Le Bail [4] as well. Impurities were present in the whole set of experiments and they were identified and refined as well. The synthesis using the sol-gel technique seemed to be the one with less impurities of the whole set of experiments but we found some differences in the X Ray Diffractogram as it was previously reported.

[1] A. Aliabadi, Y. Akhavan Farshchi, M. Akhavan, Physica C 469, 2012–2014 (2009).

[2] A. Tavana and M. Akhavan, Eur. Phys. J. B (2009).

[3] H.M. Rietveld, A profile refinement method for nuclear and magnetic structures, J. Appl. Cryst. 2 (1969) 65-71.

[4] A. Le Bail, H. Duroy & J.L. Fourquet, Mat. Res. Bull. 23 (1988) 447-452.

42

Useful Information:

Local Contacts

Leopoldo Suescun/Ricardo Faccio

[email protected] or [email protected] or [email protected]

Cátedra de Física, Facultad de Química

Anexo J.P. Sáenz, Isidoro de María 1620, 4to Piso.

Tel: 2929 0648/2924 9859

Fax: 2924 1906 (shared)

Hotel Information

Hotel Lancaster

Gian Franco Speranza

Address: Plaza Cagancha 1334

Phone: 2902 1054

Hotel Austral

Address: Héctor Gutiérrez Ruiz 1296

Phone: 2902 0108

Facultad de Química – Universidad de la República

Avenida General Flores 2124

between Yatay and Isidoro de María

Phone: 2924 1851

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