Ga. Guirgis et al., CONFORMATIONAL STABILITY, STRUCTURAL PARAMETERS, VIBRATIONAL FREQUENCIES, AND RAMAN AND INFRARED INTENSITIES OF ALLYLSILANE, Structural chemistry, 9(4), 1998, pp. 265-277
The Raman spectra (3500 to 30 cm(-1)) of allylsilane, CH2CHCH2SiH3, in
the liquid with quantitative depolarization ratios and solid states a
nd the infrared spectra (3500 to 30 cm(-1)) of the gas and solid have
been recorded. Similar data have also been recorded for the Si-d(3) is
otopomer. Additionally, the mid-infrared spectra of the normal sample
dissolved in liquified xenon as a function of temperature (-100 to -50
degrees C) have been recorded. All these data indicate there is a sin
gle conformer, the gauche rotamer, in all three physical states. Utili
zing the Si-H stretching frequencies from the infrared spectrum of the
gaseous CH2CHCH2SiD2H isotopomer, the three Si-H band distances (r(0)
) are calculated to be 1.484 Angstrom for the gauche conformer. The ot
her ro parameters are estimated from the previously reported rotationa
l constants. The fundamental frequencies for the asymmetric (78 cm(-1)
) and SiH3 (137 cm(-1)) torsions were obtained from sum and difference
bands with the SiH3 stretches. From the SiH3 torsional frequency the
barrier to internal rotation is calculated to have a value of 731 cm(-
1) (8.74 kJ/mol). The optimized geometries, conformational stabilities
, harmonic force fields, infrared intensities, Raman activities, depol
arization ratios, and vibrational frequencies have been obtained from
RHF/6-31G* and/or MP2/6-31G* ab initio calculations. These quantities
are compared to the corresponding experimental quantities when appropr
iate as well as with some corresponding results for some similar molec
ules.