Reactions of trichloromethyl radicals with organosilicon compounds

Abstract

The photolysis of carbon tetrachloride in the presence of a number of organosilicon compounds has been investigated in the gas phase. The products obtained from the photolysis experiments were those expected from a chain reaction in which trichloromethyl radicals abstract hydrogen atoms from the organosilane. Arrhenius parameters for hydrogen atom transfer were determined relative to those for trichloromethyl radical combination. The activation energies for the reaction of methyl, trifluoromethyl, and trichloromethyl radicals with organosilicon compounds are compared and the results rationalized in terms of polar effects.

Structural and Chemical Properties of Silyl Radicals

“…In the limiting case of complete electron transfer, the resulting ion pair would not be subject to any restriction in its relative rotational motion; this gain of two rotational degrees of freedom in the transition state would enhance the preexponential factor by ca. 102. Therefore, electron transfer may be extensive in the EtsSi'/CCU transition state.…”