Raman and infrared spectra, quantum chemical calculations, conformations and spectral assignments of 1-chloro-1-methyl-1-silacyclohexane

The infrared and Raman spectra of 1-chloro-1-methyl-1-silacyclohexane were recorded between 293 and 78 K, and a conformational equilibrium was established in the vapor, liquid, supercooled liquid and solid plastic phases. The a(Cl) had lower enthalpy than e(Cl); only a(Cl) was present in the crystal. DFT calculations revealed ΔH(e(Cl)-a(Cl)) to be in the range 3.2-2.4 kJ mol−1. The 32 A′ and 25 A″ modes of both conformers were assigned from the spectra and supported by B3LYP/cc-PVTZ calculations in the anharmonic approximation.