Premium
Spectra and structures of silicon‐containing compounds. XX —Raman and infrared spectra, conformational stability, vibrational assignment and ab Initio calculations of methylvinyldifluorosilane
Author(s) -
Durig J. R.,
Guirgis Gamil A.,
Qtaitat Mohammad A.
Publication year - 1995
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250260605
Subject(s) - conformational isomerism , raman spectroscopy , infrared , chemistry , ab initio , ab initio quantum chemistry methods , infrared spectroscopy , molecule , computational chemistry , crystallography , organic chemistry , physics , optics
The Raman (3100—10 cm −1 ) and infrared (3100—40 cm −1 ) spectra of methylvinyldifluorosilane, CH 2 CHSiF 2 CH 3 , were recorded for the gas and solid. Additionally, the Raman spectrum of the liquid was recorded and qualitative depolarization values were obtained. The observed bands in the fluid states are assigned on the basis of the more stable gauche (antiperiplanar) conformer where one of the fluorine atoms is eclipsing the double bond and the less stable cis (synplanar) conformer. However, in the annealed crystalline solid, only the cis conformer remains. A complete vibrational assignment is proposed for both conformers based on infrared band contours, Raman depolarization data, group wavenumbers and normal coordinate calculations. The experimental stability, barriers to internal rotation, and fundamental vibrational wavenumbers are compared with those obtained from the ab initio calculations employing the RHF/3‐21G * , RHF/6‐31G * and MP2/6‐31G * basis sets and to the corresponding quantities obtained for some similar molecules.