G.A. Guirgis et al. / Spectrochimica Acta Part A 56 (2000) 1957–1970
1969
Acknowledgements
However, most of the other fundamentals for the
two conformers have similar wavenumbers, which
is consistent with similar force constants for the
two rotamers.
JRD acknowledges partial support of these
studies by the University of Missouri–Kansas
City Faculty Research Grant program.
The conformational stability of vinyldichlorosi-
lane can be compared with the corresponding
three-membered ring molecule, dichlorocyclo-
propylsilane. The variable temperature studies
[10] of the infrared spectra Of c-C3H5SiHCl2 dis-
solved in liquified xenon indicated that the gauche
form is the more stable conformer in agreement
with the ab initio calculations at all levels of the
theory explored with electron correlation. This
observation is exactly the same as found for
chlorovinylsilane study [9] where all levels of ab
initio calculations are consistent with the experi-
mental results. Therefore, for these two molecules
it appears that the ab initio calculations with these
basis sets correctly predict the conformational
stability of these types of silyl chloride molecules.
However, this observation was not the case for
References
[1] R. Huag, H. Weinmann, B. Yoachim, F. Aldinger, J. Eur.
Ceram. Soc. 19 (1999) 1.
[2] V. Belot, R.J.P. Corriu, D. Leclercq, D.H. Mutin, A.
Viox, J. Non-Cryst. Solids 176 (1994) 33.
[3] K. Tamura, Y. Mori, Japanese Patent no. 04166942.
[4] B. Boury, RJ.P. Corriu, D. Leclercq, D.H. Muti, J.M.
Planneix, A. Vioux, NATO AST, Sec., E, 1992.
[5] B. Boury, L. Carpenter, R.J.P. Corriu, Angew Chem. 102
(1990) 818.
[6] Y. Pentin, Zh. Prilel, Spectiosk. 24 (1976) 870.
[7] M.D. Allendorf, C.F. Melius, J. Phys. Chem. 97 (1993)
720.
[8] T.K. Gounev, J.W. Weston, S. Shen, M. Dakkouri, A.
Grunvogel-Hurst, J.R. Durig, J. Phys. Chem. A 101
(1997) 8614.
[9] J.R. Durig, Y.E. Nashed, M.A. Qtaitat, G.A. Guirgis, J.
Mol. Struct. (2000) in press.
[10] J.R. Durig, S.W. Hur, M. Dakkouri, A. Grunvogel-
Hurst, T.K. Gounev, Chem. Phys. 226 (1998) 125.
[11] F.A. Miller, B.M. Harney, Appl. Spectrosc. 24 (1970)
291.
[12] M.J. Frisch, G.W. Trucks, H.B. Schlegel, P.M.W. Gill,
B.K. Johnson, M.A. Robb, J.R. Cheeseman, T.A. Keith,
G.A. Petersson, J.A. Montgomery, K. Raghavachari,
M.A. AI-Laham, V.G. Zakrzewski, J.V. Ortiz, J.B. Fores-
man, J. Cioslowski, B.B. Stefanov, A. Nanayakkara, M.
Challacombe, C.Y. Peng, P.Y. Ayala, W. Chen, M.W.
Wong, J.L. Andres, E.S. Replogle, R. Gomperts, R.L.
Martin, D.J. Fox, J.S. Binkley, D.J. Defrees, J. Baker,
J.P. Stewart, M. Head-Gordon, C. Gonzalez, J.A. Pople,
Gaussian 94 (revision B. 3), Gaussian Inc., Pittsburgh PA,
1995.
chlorocyclopropylsilane,
c-C3H5SiH2Cl,
and
vinyldichlorosilane, CH2CHSiCl2, where the ab
initio calculation is in agreement with the experi-
mental data only with relatively large basis sets. It
would be of interest to investigate whether similar
agreements with the ab initio predicted and exper-
imental values for the conformer stabilities for the
corresponding
fluoride
molecules,
i.e.
CH2CHSiHF2 and c-C3H5SiH2F are found for
only large basis sets.
The vibrational assignments for vinyldichlorosi-
lane had not previously been completely reported
[6]. However, because it was not possible to ob-
tain the spectrum of a single conformer from the
solid, it was difficult to distinguish which bands
were due to which conformer. Nevertheless, the
ab initio values were used to make the vibrational
assignment for the most part. Using a scaling
factor of 0.90 for all modes except 1.0 for the
asymmetric torsion, the wavenumbers for the fun-
damentals are predicted from the MP2/6-31G(d)
ab initio calculation to be within 2% for both
conformers. Therefore, ab initio calculations at
this level provide excellent predictions of the
wavenumbers for the fundamentals for these types
of silyl molecules.
[13] P. Pulay, Mol. Phys. 17 (1969) 197.
[14] J.H. Schachtschneider, Vibrational Analysis of Poly-
atomic Molecules, Parts V, VI, Technical report nos. 231,
57, Shell Development Co., Houston, TX, 1964, 1965.
[15] M.J. Frisch, Y. Yamaguchi, J.F. Gaw, H.F. Schaefer III,
J.S. Binkley, J. Chem. Phys. 84 (1986) 531.
[16] R.D. Amos, Chem. Phys. Lett. 124 (1986) 376.
[17] P.L. Polavarapu, J. Phys. Chem. 94 (1990) 8106.
[18] G.W. Chantry, in: A. Anderson (Ed.), The Raman Effect,
Ch. 2, vol. 1, Marcel Dekker, New York, 1971.
[19] W.A. Herrebout, B.J. van der Veken, A. Wang, J.R.
Durig, J. Phys. Chem. 99 (1995) 578.
[20] W.A. Herrebout, B.J. van der Veken, J. Chem. Phys. 100
(1996) 9671.