Autoxidation of poly(hydrosilane)s

Poly(hydrosilane)s obtained by dehydrocoupling of the corresponding RSiH(3) were found to be air sensitive. Analyses based on GPC, IR, and heterocorrelated (1)H-(29)Si NMR indicate the formation of some siloxane-type structures on the polymer backbone. Kinetic studies carried out by EPR spectroscopy using fusinite as a paramagnetic probe of the oxygen concentration allowed the oxidizability of some polysilanes to be obtained. Oxidizability values of 1.2 x 10(-2) and 1.8 x 10(-2) M(-1/2) s(-1/2) were found for poly(n-hexylsilane) and poly(phenylsilane), respectively. Model studies on the oxidation of (Me(3)Si)(2)Si(H)Me with a mixture of (16)O(2) and (18)O(2) suggest that the main reaction path proceeds via a free-radical chain mechanism and involves either two or three consecutive, unimolecular steps. Poly(hydrosilane)s react with nitroxides (TEMPO) under free-radical conditions and in the absence of molecular oxygen to give the corresponding amine in good yields.