29Si and 13C Nuclear magnetic resonance studies of organosilicon chemistry

Abstract

Silicon-29 spin-lattice relaxation times and ²⁹Si{₁H} nuclear Overhauser enhancements are reported for five trialkylsilanes and fo sym-tetramethyldisiloxane, all of which contain a direct SiH bond. Relaxation rate contributions from (Si, H) dipolar interactions and fro other mechanisms are evaluated and discussed in terms of molecular mobility. For the smaller molecules it is concluded that the spin-rotation contribution to (T₁)^-1 is dominant but, when the alkyl groups are bigger than ethyl, dipolar interactions are more important than spin-rotation. Silicon-29 chemical shifts and coupling constants are also presented and briefly discussed.