Structures and energetics of axial and equatorial 1-methyl-1-silacyclohexane

摘要

The structural differences and the relative energies for the axial and equatorial forms of 1-methyl-1-silacyclohexane have been obtained from the rotational spectra of the normal, Si-29, and all C-13 isotopologues of the axial and equatorial forms, observed by molecular beam Fourier transform microwave spectroscopy. The two species appear to have the same energy, within uncertainty limits, Delta E = 0.0 +/- 0.2 kcal/mol. Structural parameters (r(0) and r(s)) are given for the two forms. The main structural differences are discussed. Potential barriers for the methyl group internal rotations (V-3) have been determined for both conformers to be 1.26(1) and 1.48(2) kcal/mol for the axial and equatorial species, respectively.