Theoretical and spectroscopic studies of the conformations of permethylpolysilanes and related molecules, 1. SCF studies and comparisons of the molecular structures of dimethyl ether and disiloxane, 2

The conformational properties of decamethyltetrasilane were studied by variable temperature NMR and vibrational (IR and Raman) spectroscopy. Variable temperature H-1 and C-13 nmr were also studied and at very low temperatures, broadening of the two proton resonances (SIME2, SIME3) is observed, although temperatures low enough to achieve decoalescence could not be attained. However, by approximate lineshape analysis of the spectra, the activation energy could be estimated as 2.21 kcal/mole. Comparisons of the thermodynamic and kinetic conformational parameters with those of related systems are also presented. Pseudopotential SCF calculations of the molecular structures of the simple compounds, (H3SI)2O and (H3C)2O were undertaken to study the extent and importance of d orbital participation.