Autoxidation of Poly(hydrosilane)s
journal contributionposted on 28.04.1998, 00:00 by Chryssostomos Chatgilialoglu, Andrea Guerrini, Marco Lucarini, Gian Franco Pedulli, Primo Carrozza, Giovanni Da Roit, Valerio Borzatta, Vittorio Lucchini
Poly(hydrosilane)s obtained by dehydrocoupling of the corresponding RSiH3 were found to be air sensitive. Analyses based on GPC, IR, and heterocorrelated 1H−29Si 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 × 10-2 and 1.8 × 10-2 M-1/2 s-1/2 were found for poly(n-hexylsilane) and poly(phenylsilane), respectively. Model studies on the oxidation of (Me3Si)2Si(H)Me with a mixture of 16O2 and 18O2 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.