Indexed on: 27 May '14Published on: 27 May '14Published in: Structural Chemistry
Molecular structure and conformational behavior of the title compound 1 were studied experimentally by gas-phase electron diffraction (GED–MS) and theoretically (DFT and MP2). Only two of four possible conformers of 1 differing by axial or equatorial location of the phenyl group and the angle of rotation about the Si–CPh bond contribute to the equilibrium; these are the 1-eq conformer with the phenyl ring plane perpendicular to the averaged silacyclohexane plane and the 1-ax conformer with the phenyl ring and Si–C6 bond lying approximately in one plane. The ratio 1-eq:1-ax is 62 (10):38 (10), which is only slightly different from 78:22 in solution. The presence of up to 10 % of 1-ax_orth conformer cannot be excluded either. The corresponding ΔG values are 0.29 and 0.25 kcal mol−1. The GED molecular structure of 1 is nicely reproduced by DFT and MP2 calculations.