Adsorption of CH 2 CClF and CH 2 CBrF on TiO 2 : infrared spectroscopy and quantum-mechanical...
1
Adsorption of CH Adsorption of CH 2 2 CClF and CH CClF and CH 2 2 CBrF on TiO CBrF on TiO 2 2 : : infrared spectroscopy and quantum-mechanical infrared spectroscopy and quantum-mechanical calculations calculations Jessica Scaranto and Santi Giorgianni Università Ca’ Foscari di Venezia – Dipartimento di Chimica Fisica, Calle Larga S. Marta 2137, I-30123 Venezia, Italy The toxicity of the halogenated ethenes, which are compounds widely employed in the industrial field, represents a serious problem for the human health. Heterogeneous The toxicity of the halogenated ethenes, which are compounds widely employed in the industrial field, represents a serious problem for the human health. Heterogeneous photocatalysis on TiO photocatalysis on TiO 2 represents a promising approach for removing these compounds from the air [1]. Since the decomposition occurs after the adsorption, a study on the represents a promising approach for removing these compounds from the air [1]. Since the decomposition occurs after the adsorption, a study on the nature of the adsorbate-substrate interaction can lead to useful information for a complete understanding of the reaction mechanisms and then, for the develop of nature of the adsorbate-substrate interaction can lead to useful information for a complete understanding of the reaction mechanisms and then, for the develop of successful applications. successful applications. In a recent work, In a recent work, the adsorption of vinyl halides at room temperature was investigated by IR spectroscopy [2]: according to the results it has the adsorption of vinyl halides at room temperature was investigated by IR spectroscopy [2]: according to the results it has been concluded that these molecules adsorb by an acid-base interaction through the halogen atom and the surface Lewis acid site (Ti been concluded that these molecules adsorb by an acid-base interaction through the halogen atom and the surface Lewis acid site (Ti 4+ 4+ ), and an H-bond through the CH ), and an H-bond through the CH 2 group group and a surface Lewis basic site (O and a surface Lewis basic site (O 2- 2- or OH or OH - ). This adsorbate-substrate model was successively studied by periodic quantum-mechanical calculations [3,4]. ). This adsorbate-substrate model was successively studied by periodic quantum-mechanical calculations [3,4]. The aim of the present work is to formulate an adsorption model of the 1-chloro-1-fluoroethene (CH The aim of the present work is to formulate an adsorption model of the 1-chloro-1-fluoroethene (CH 2 CClF) and 1-bromo-1-fluoroethene (CH CClF) and 1-bromo-1-fluoroethene (CH 2 CBrF) on TiO CBrF) on TiO 2 at room temperature at room temperature through the analysis of the FTIR spectra of the adsorbed molecules. The attention has been focused on the adsorbate absorptions above 1000 cm through the analysis of the FTIR spectra of the adsorbed molecules. The attention has been focused on the adsorbate absorptions above 1000 cm -1 -1 and in particular on the and in particular on the bands related to the C-H, C=C and C-F stretching modes. The approximate description of the vibrations of the adsorbates has been carried out by comparing the related bands related to the C-H, C=C and C-F stretching modes. The approximate description of the vibrations of the adsorbates has been carried out by comparing the related absorptions with those of the compounds in the gas-phase. In order to obtain information on the variation of the molecular structural parameters, a periodic quantum- absorptions with those of the compounds in the gas-phase. In order to obtain information on the variation of the molecular structural parameters, a periodic quantum- mechanical study according to the formulated model has been performed; the calculations have been carried out by considering the rutile (110) which represents the most mechanical study according to the formulated model has been performed; the calculations have been carried out by considering the rutile (110) which represents the most stable surface of TiO stable surface of TiO 2 [5]. [5]. IR spectroscopy IR spectroscopy Experimental Details Experimental Details Pre-treatment of TiO Pre-treatment of TiO 2 TiO 2 powder (Degussa P25) [pellet of 20 mg . cm -2 ] T = 723 K, P ~ 10 -4 Torr, t = 5 h re-oxidation with mix N 2 /O 2 Residual surface hydroxyl groups around 3700 cm -1 The pre-treated surface contains two surface Lewis acid sites which differ in the electrophilicity Adsorption spectra Adsorption spectra Background (TiO 2 after the pre- treatment) Introduction of the gas (0.5 – 2.0 Torr) 20 scans at resolution of 4 cm -1 Proposed adsorption Proposed adsorption model model No H-bond between CH 2 group and surface Lewis basic site (O 2- or OH - ) Acid-base interaction between surface Lewis acid site and a molecular basic site (F atom or C=C bond) Ti O O F Cl H H Ti O O Cl F H H Structure I Structure II X = Cl, B r Computational Computational details details Program Program CRYSTAL03 [7] CRYSTAL06 [8] Method Method DFT/B3LYP [9] Basis set Basis set Ti : DVAE (86-51G* ) [10] O : TVAE (8-411G) [10] CH 2 CFX : standard 6-31G** [11- 13] Rutile (110) surface Rutile (110) surface References References [1] Linsebigler, A. L.; Lu, G.; Yates Jr., J. T. Chem. Rev. 1995, 95, 735. [2] Scaranto, J.; Pietropolli Charmet, A.; Stoppa, P.; Giorgianni, S. J. Mol. Struct. 2005, 741, 213. [3] Scaranto, J.; Mallia, G; Giorgianni, S.; Zicovich-Wilson, C. M.; Civalleri, B.; Harrison, N. M. Surf. Sci. 2006, 600, 305. [4] Scaranto, J.; Giorgianni, S. J. Phys. Chem. C 2007, 111, 11039. [5] Diebold, U. Surf. Sci. Rep. 2003, 48, 53. [6] Mann, D. E.; Acquista, N; Plyler, E. K. J. Chem. Phys. 1955, 23, 2122. [7] Saunders, V. R.; Dovesi, R.; Roetti, C.; Orlando, R.; Zicovich-Wilson C. M.; Harrison, N. M.; Doll, K.; Civalleri, B.; Bush, I. J.; D’Arco, P.; Llunell, M. CRYSTAL03 User’s Manual, University of Torino (Torino, 2003). [8] Dovesi, R.; Saunders, V. R.; Roetti, C.; Orlando, R.; Zicovich-Wilson C. M.; Pascale, F; Civalleri, B.; Doll, K.; Harrison, N. M.; Bush, I. J.; D’Arco, P.; Llunell, M. CRYSTAL06 User’s Manual, University of Torino (Torino, 2006). [9] Becke, A.D. J. Chem. Phys. 1993, 98, 5648. [10] Muscat, J. PhD Thesis, University of Manchester, 1999. [11] Hariharan, P. C.; Pople, J. A. Theoret. Chim. Acta 1973, 28, 213. [12] Francl, M. M.; Petro, W. J.; Hehre W. J.; Binkley J. S.; Gordon, M. S.; DeFrees D. J.; Pople J. A. J. Chem. Phys. 1982, 77, 3654. [13] Rassolov, V. A.; Ratner, M. A.; Pople, J. A.; Redfern, P. C.; Curtiss, L.A. J. Comp. Chem. 2001, 22, 976. Quantum-mechanical calculations Quantum-mechanical calculations Calculated structuralparam eters A dsorbed a Free Structure I % Structure II % C 1 -C 2 1.326 1.321 -0.4 1.331 0.4 C 1 -Cl 1.739 1.728 -0.6 1.734 -0.3 C 1 -F 1.333 1.358 1.9 1.330 -0.2 C 2 -H 1 1.081 1.080 -0.1 1.082 0.1 C 2 -H 2 1.083 1.080 -0.3 1.084 0.1 Cl-C 1 -C 2 125.1 125.9 0.6 125.2 0.1 F-C 1 -C 2 123.2 123.2 0.0 123.1 -0.1 H 1 -C 2 -C 1 121.0 120.6 -0.3 120.3 -0.6 H 2 -C 2 -C 1 119.3 120.9 1.3 118.6 -0.6 F-Ti 2.557 C 1 -Ti 3.763 C 2 -Ti 3.237 Ti-F-C 1 148.2 Ti-C 1 -C 2 57.0 Ti-C 2 -C 1 102.8 Lengthsand anglesare reported in Å and degrees, respectively. a :% refersto the isolated optim ised m olecule (Free). Calculated vibrationalfrequencies A dsorbed Free Structure I Structure II Vibration A pprox. description W avenum ber W avenum ber W avenum ber 1 CH 2 asym stretch 3179 3202 3077 2 CH 2 sym stretch 3082 3110 2989 3 C=C stretch 1675 1668 1603 4 CH 2 bend 1361 1350 1298 5 C-F stretch 1166 1120 1076 6 CH 2 rock 927 897 862 7 C-Clstretch 694 664 638 8 CClF bend 412 412 396 9 CClF rock 357 372 357 10 CH 2 w ag 819 824 791 11 torsion 658 652 626 12 CClF w ag 510 479 460 W avenum bersare given in cm -1 . The vibrationalfrequencieshave been scaled by using a scaling factorequalto 0.961. CH 2 CClF molecule Structure I Structure II E int = -20.19 E int = -15.41 F Cl C 1 C 2 H 1 H 2 CH CH 2 CCl CCl F F Experimentalvibrationalfrequencies CH 2 CClF a (gas) CH 2 CClF/TiO 2 Vibration Approx.description W avenum ber W avenum ber 1 CH 2 asym stretching 3069 3140 2 CH 2 sym stretching 3016 3050 3 C=C stretching 1656 1654 1624 4 CH 2 bending 1383 1360 5 C-F stretching 1186 1186;1168 b 1135;1118 b W avenum bersare given in cm -1 . a :from ref. [6]. b :the tw o frequenciesreferto the presence oftw o surface Lew isacid sites. IR spectra of CH 2 CClF in gas-phase and adsorbed on TiO 2 . (a) Room temperature, P ~ 1.0 Torr, 16 cm cell; the spectrum in the region 3800-2850 cm -1 has been multiplied by a factor of 10. Infrared spectrum of TiO 2 taken after being in contact with ~ 0.6 (b) and ~ 1.2 (c) Torr of CH 2 CClF at room temperature. CH CH 2 CBrF CBrF IR spectra of CH 2 CBrF in gas-phase and adsorbed on TiO 2 . (a) Room temperature, P ~ 1.0 Torr, 16 cm cell; the spectrum in the region 3800-2850 cm -1 has been multiplied by a factor of 10. Infrared spectrum of TiO 2 taken after being in contact with ~ 0.6 (b) and ~ 1.2 (c) Torr of CH 2 CBrF at room temperature. Experimentalvibrationalfrequencies CH 2 CBrF a (gas) CH 2 CBrF/TiO 2 Vibration Approx.description W avenum ber W avenum ber 1 CH 2 asym stretching 3055 3135 2 CH 2 sym stretching 3002 3036 3 C=C stretching 1647 1643 1632 4 CH 2 bending 1369 1348 5 C-F stretching 1166 1166;1156 b 1122;1112 b W avenum bersare given in cm -1 . a :currentw ork. b :the tw o frequenciesreferto thepresence oftw o surface Lew isacid sites. Calculated structuralparam eters A dsorbed a Free Structure I % Structure II % C 1 -C 2 1.325 1.320 -0.4 1.330 0.4 C 1 -Br 1.906 1.893 -0.7 1.900 -0.3 C 1 -F 1.332 1.357 1.9 1.331 -0.1 C 2 -H 1 1.081 1.079 -0.2 1.082 0.1 C 2 -H 2 1.084 1.080 -0.4 1.085 0.1 Br-C 1 -C 2 125.0 125.1 0.1 125.1 0.1 F-C 1 -C 2 123.3 123.3 0.0 123.1 -0.2 H 1 -C 2 -C 1 121.2 120.9 -0.2 120.5 -0.6 H 2 -C 2 -C 1 119.1 120.7 1.3 118.5 -0.5 F-Ti 2.568 C 1 -Ti 3.857 C 2 -Ti 3.290 Ti-F-C 1 145.2 Ti-C 1 -C 2 55.4 Ti-C 2 -C 1 105.1 Lengthsand anglesare reported in Å and degrees, respectively. a :% refersto the isolated optim ised m olecule (Free). Calculated vibrationalfrequencies A dsorbed Free Structure I Structure II Vibration A pprox. description W avenum ber W avenum ber W avenum ber 1 CH 2 asym stretch 3175 3202 3177 2 CH 2 sym stretch 3077 3112 3072 3 C=C stretch 1660 1662 1634 4 CH 2 bend 1364 1345 1355 5 C-F stretch 1147 1099 1142 6 CH 2 rock 934 896 936 7 C-Brstretch 581 581 584 8 CBrF bend 346 353 349 9 CBrF rock 310 328 313 10 CH 2 w ag 824 826 826 11 torsion 693 646 699 12 CBrF w ag 473 432 486 W avenum bersare given in cm -1 . The vibrationalfrequencieshave been scaled by using a scaling factorequalto 0.961. F Br C 1 C 2 H 1 H 2 CH 2 CClF molecule Structure I Structure II E int = -18.47 E int = -12.80 Ti(5f) O(2f) O(3f) Ti(6f)
-
Upload
aaliyah-covin -
Category
Documents
-
view
215 -
download
1
Transcript of Adsorption of CH 2 CClF and CH 2 CBrF on TiO 2 : infrared spectroscopy and quantum-mechanical...
Adsorption of CHAdsorption of CH22CClF and CHCClF and CH
22CBrF on TiOCBrF on TiO22: infrared : infrared
spectroscopy and quantum-mechanical calculationsspectroscopy and quantum-mechanical calculations Jessica Scaranto and Santi Giorgianni
Università Ca’ Foscari di Venezia – Dipartimento di Chimica Fisica, Calle Larga S. Marta 2137, I-30123 Venezia, ItalyThe toxicity of the halogenated ethenes, which are compounds widely employed in the industrial field, represents a serious problem for the human health. Heterogeneous photocatalysis on TiOThe toxicity of the halogenated ethenes, which are compounds widely employed in the industrial field, represents a serious problem for the human health. Heterogeneous photocatalysis on TiO
22 represents a promising approach for removing these represents a promising approach for removing these
compounds from the air [1]. Since the decomposition occurs after the adsorption, a study on the nature of the adsorbate-substrate interaction can lead to useful information for a complete understanding of the reaction mechanisms and then, for the develop compounds from the air [1]. Since the decomposition occurs after the adsorption, a study on the nature of the adsorbate-substrate interaction can lead to useful information for a complete understanding of the reaction mechanisms and then, for the develop of successful applications. of successful applications. In a recent work, In a recent work, the adsorption of vinyl halides at room temperature was investigated by IR spectroscopy [2]: according to the results it has been concluded that these molecules adsorb by an acid-base interaction through the the adsorption of vinyl halides at room temperature was investigated by IR spectroscopy [2]: according to the results it has been concluded that these molecules adsorb by an acid-base interaction through the halogen atom and the surface Lewis acid site (Tihalogen atom and the surface Lewis acid site (Ti4+4+), and an H-bond through the CH), and an H-bond through the CH
22 group and a surface Lewis basic site (O group and a surface Lewis basic site (O2-2- or OH or OH--). This adsorbate-substrate model was successively studied by periodic quantum-mechanical calculations [3,4].). This adsorbate-substrate model was successively studied by periodic quantum-mechanical calculations [3,4].
The aim of the present work is to formulate an adsorption model of the 1-chloro-1-fluoroethene (CHThe aim of the present work is to formulate an adsorption model of the 1-chloro-1-fluoroethene (CH22CClF) and 1-bromo-1-fluoroethene (CHCClF) and 1-bromo-1-fluoroethene (CH
22CBrF) on TiOCBrF) on TiO22 at room temperature through the analysis of the FTIR spectra of the adsorbed molecules. The at room temperature through the analysis of the FTIR spectra of the adsorbed molecules. The
attention has been focused on the adsorbate absorptions above 1000 cmattention has been focused on the adsorbate absorptions above 1000 cm -1-1 and in particular on the bands related to the C-H, C=C and C-F stretching modes. The approximate description of the vibrations of the adsorbates has been carried out by comparing and in particular on the bands related to the C-H, C=C and C-F stretching modes. The approximate description of the vibrations of the adsorbates has been carried out by comparing the related absorptions with those of the compounds in the gas-phase. In order to obtain information on the variation of the molecular structural parameters, a periodic quantum-mechanical study according to the formulated model has been performed; the the related absorptions with those of the compounds in the gas-phase. In order to obtain information on the variation of the molecular structural parameters, a periodic quantum-mechanical study according to the formulated model has been performed; the calculations have been carried out by considering the rutile (110) which represents the most stable surface of TiOcalculations have been carried out by considering the rutile (110) which represents the most stable surface of TiO
22 [5]. [5].
IR spectroscopyIR spectroscopy
Experimental DetailsExperimental Details
Pre-treatment of TiOPre-treatment of TiO22
TiO2 powder (Degussa P25)
[pellet of 20 mg.cm-2]T = 723 K, P ~ 10-4 Torr, t = 5 h
re-oxidation with mix N2/O2
Residual surface hydroxyl groups around 3700 cm-1
The pre-treated surface contains two surface Lewis acid sites which differ in
the electrophilicity
Adsorption spectraAdsorption spectraBackground
(TiO2 after the pre-treatment)
Introduction of the gas (0.5 – 2.0 Torr)
20 scans at resolution of 4 cm-1
Proposed adsorption modelProposed adsorption model
No H-bond between CH2 group and surface Lewis basic site (O2- or OH-)
Acid-base interaction between surface Lewis acid site and a molecular basic
site (F atom or C=C bond)
Ti
O O
F
Cl
H
H
Ti
O O
Cl
F H
H
Structure I Structure II
X = Cl, Br
Computational detailsComputational details
ProgramProgram
CRYSTAL03 [7]CRYSTAL06 [8]
MethodMethod
DFT/B3LYP [9]
Basis setBasis set
Ti : DVAE (86-51G* ) [10]O : TVAE (8-411G) [10]
CH2CFX : standard 6-31G** [11-13]
Rutile (110) surfaceRutile (110) surface
ReferencesReferences[1] Linsebigler, A. L.; Lu, G.; Yates Jr., J. T. Chem. Rev. 1995, 95, 735.[2] Scaranto, J.; Pietropolli Charmet, A.; Stoppa, P.; Giorgianni, S. J. Mol. Struct. 2005, 741, 213.[3] Scaranto, J.; Mallia, G; Giorgianni, S.; Zicovich-Wilson, C. M.; Civalleri, B.; Harrison, N. M. Surf. Sci. 2006, 600, 305. [4] Scaranto, J.; Giorgianni, S. J. Phys. Chem. C 2007, 111, 11039.[5] Diebold, U. Surf. Sci. Rep. 2003, 48, 53.[6] Mann, D. E.; Acquista, N; Plyler, E. K. J. Chem. Phys. 1955, 23, 2122.[7] Saunders, V. R.; Dovesi, R.; Roetti, C.; Orlando, R.; Zicovich-Wilson C. M.; Harrison, N. M.; Doll, K.; Civalleri, B.; Bush, I. J.; D’Arco, P.; Llunell, M. CRYSTAL03 User’s Manual, University of Torino (Torino, 2003).[8] Dovesi, R.; Saunders, V. R.; Roetti, C.; Orlando, R.; Zicovich-Wilson C. M.; Pascale, F; Civalleri, B.; Doll, K.; Harrison, N. M.; Bush, I. J.; D’Arco, P.; Llunell, M. CRYSTAL06 User’s Manual, University of Torino (Torino, 2006).[9] Becke, A.D. J. Chem. Phys. 1993, 98, 5648.[10] Muscat, J. PhD Thesis, University of Manchester, 1999.[11] Hariharan, P. C.; Pople, J. A. Theoret. Chim. Acta 1973, 28, 213.[12] Francl, M. M.; Petro, W. J.; Hehre W. J.; Binkley J. S.; Gordon, M. S.; DeFrees D. J.; Pople J. A. J. Chem. Phys. 1982, 77, 3654.[13] Rassolov, V. A.; Ratner, M. A.; Pople, J. A.; Redfern, P. C.; Curtiss, L.A. J. Comp. Chem. 2001, 22, 976.
Quantum-mechanical calculationsQuantum-mechanical calculations
CCaallccuullaatteedd ssttrruuccttuurraall ppaarraammeetteerrss
AAddssoorrbbeeddaa
FFrreeee
SSttrruuccttuurree II %% SSttrruuccttuurree IIII %% C1-C2 1.326 1.321 -0.4 1.331 0.4 C1-Cl 1.739 1.728 -0.6 1.734 -0.3 C1-F 1.333 1.358 1.9 1.330 -0.2 C2-H1 1.081 1.080 -0.1 1.082 0.1 C2-H2 1.083 1.080 -0.3 1.084 0.1
Cl-C1-C2 125.1 125.9 0.6 125.2 0.1 F-C1-C2 123.2 123.2 0.0 123.1 -0.1 H1-C2-C1 121.0 120.6 -0.3 120.3 -0.6 H2-C2-C1 119.3 120.9 1.3 118.6 -0.6
F-Ti 2.557 C1-Ti 3.763 C2-Ti 3.237
Ti-F-C1 148.2 Ti-C1-C2 57.0 Ti-C2-C1 102.8
Lengths and angles are reported in Å and degrees, respectively.
a: % refers to the isolated optimised molecule (Free).
CCaallccuullaatteedd vviibbrraattiioonnaall ffrreeqquueenncciieess
AAddssoorrbbeedd
FFrreeee SSttrruuccttuurree II SSttrruuccttuurree IIII
VViibbrraattiioonn AApppprrooxx..
ddeessccrriippttiioonn WWaavveennuummbbeerr WWaavveennuummbbeerr WWaavveennuummbbeerr
1 CH2 asym stretch 3179 3202 3077
2 CH2 sym stretch 3082 3110 2989
3 C=C stretch 1675 1668 1603
4 CH2 bend 1361 1350 1298
5 C-F stretch 1166 1120 1076
6 CH2 rock 927 897 862
7 C-Cl stretch 694 664 638
8 CClF bend 412 412 396
9 CClF rock 357 372 357
10 CH2 wag 819 824 791
11 torsion 658 652 626
12 CClF wag 510 479 460
Wavenumbers are given in cm-1. The vibrational frequencies have been scaled by using a scaling factor equal to 0.961.
CH2CClF molecule Structure I Structure II Eint = -20.19 Eint = -15.41
F
Cl
C1 C2
H1
H2
CHCH22CClFCClF
EExxppeerriimmeennttaall vviibbrraattiioonnaall ffrreeqquueenncciieess
CCHH22CCCCllFFaa((ggaass)) CCHH22CCCCllFF//TTiiOO22
VViibbrraattiioonn AApppprrooxx.. ddeessccrriippttiioonn WWaavveennuummbbeerr WWaavveennuummbbeerr
1 CH2 asym stretching 3069 3140
2 CH2 sym stretching 3016 3050
3 C=C stretching 1656
1654 1624
4 CH2 bending 1383 1360
5 C-F stretching 1186
1186; 1168 b
1135; 1118 b Wavenumbers are given in cm-1.
a: from ref. [6]. b: the two frequencies refer to the presence of two surface Lewis acid sites.
IR spectra of CH2CClF in gas-phase and adsorbed on TiO2. (a) Room temperature,
P ~ 1.0 Torr, 16 cm cell; the spectrum in the region 3800-2850 cm -1 has been multiplied by a factor of 10. Infrared spectrum of TiO2 taken after being in contact
with ~ 0.6 (b) and ~ 1.2 (c) Torr of CH2CClF at room temperature.
CHCH22CBrFCBrF
IR spectra of CH2CBrF in gas-phase and adsorbed on TiO2. (a) Room temperature,
P ~ 1.0 Torr, 16 cm cell; the spectrum in the region 3800-2850 cm -1 has been multiplied by a factor of 10. Infrared spectrum of TiO2 taken after being in contact
with ~ 0.6 (b) and ~ 1.2 (c) Torr of CH2CBrF at room temperature.
EExxppeerriimmeennttaall vviibbrraattiioonnaall ffrreeqquueenncciieess
CCHH22CCBBrrFFaa((ggaass)) CCHH22CCBBrrFF//TTiiOO22
VViibbrraattiioonn AApppprrooxx.. ddeessccrriippttiioonn WWaavveennuummbbeerr WWaavveennuummbbeerr
1 CH2 asym stretching 3055 3135
2 CH2 sym stretching 3002 3036
3 C=C stretching 1647
1643 1632
4 CH2 bending 1369 1348
5 C-F stretching 1166
1166; 1156 b
1122; 1112 b Wavenumbers are given in cm-1.
a: current work. b: the two frequencies refer to the presence of two surface Lewis acid sites.
CCaallccuullaatteedd ssttrruuccttuurraall ppaarraammeetteerrss
AAddssoorrbbeeddaa
FFrreeee
SSttrruuccttuurree II %% SSttrruuccttuurree IIII %% C1-C2 1.325 1.320 -0.4 1.330 0.4 C1-Br 1.906 1.893 -0.7 1.900 -0.3 C1-F 1.332 1.357 1.9 1.331 -0.1 C2-H1 1.081 1.079 -0.2 1.082 0.1 C2-H2 1.084 1.080 -0.4 1.085 0.1
Br-C1-C2 125.0 125.1 0.1 125.1 0.1 F-C1-C2 123.3 123.3 0.0 123.1 -0.2 H1-C2-C1 121.2 120.9 -0.2 120.5 -0.6 H2-C2-C1 119.1 120.7 1.3 118.5 -0.5
F-Ti 2.568 C1-Ti 3.857 C2-Ti 3.290
Ti-F-C1 145.2 Ti-C1-C2 55.4 Ti-C2-C1 105.1
Lengths and angles are reported in Å and degrees, respectively.
a: % refers to the isolated optimised molecule (Free).
CCaallccuullaatteedd vviibbrraattiioonnaall ffrreeqquueenncciieess
AAddssoorrbbeedd
FFrreeee SSttrruuccttuurree II SSttrruuccttuurree IIII
VViibbrraattiioonn AApppprrooxx..
ddeessccrriippttiioonn WWaavveennuummbbeerr WWaavveennuummbbeerr WWaavveennuummbbeerr
1 CH2 asym stretch 3175 3202 3177
2 CH2 sym stretch 3077 3112 3072
3 C=C stretch 1660 1662 1634
4 CH2 bend 1364 1345 1355
5 C-F stretch 1147 1099 1142
6 CH2 rock 934 896 936
7 C-Br stretch 581 581 584
8 CBrF bend 346 353 349
9 CBrF rock 310 328 313
10 CH2 wag 824 826 826
11 torsion 693 646 699
12 CBrF wag 473 432 486
Wavenumbers are given in cm-1. The vibrational frequencies have been scaled by using a scaling factor equal to 0.961.
F
Br
C1 C2
H1
H2
CH2CClF molecule Structure I Structure II Eint = -18.47 Eint = -12.80
Ti(5f)O(2f)
O(3f)Ti(6f)
