Molecular structure and conformational analysis of 3-methyl-3-silathiane by gas phase electron diffraction, FTIR spectroscopy and quantum chemical calculations

Abstract

Molecular structure and conformational behavior of 3-methyl-3-silathiane 1 was studied by gas phase electron diffraction, FTIR and theoretical calculations (DFT, MP2). Two conformers, 1-ax and 1-eq, were located on the potential energy surface. GED, FTIR and Raman spectroscopic measurements in the gas phase and in heptane solution, as well as the MP2/cc-pVTZ calculations give nearly the same ratio of the conformers 1-ax:1-eq of ca. 3:2. The GED experimental geometric and vibrational parameters of 1 are well predicted by theoretical calculations at MP2/6-311G** level. The results of FTIR spectroscopy are indicative of the increase of population of 1-eq conformer on lowering the temperature or on going to a polar medium.