Photolysis of tris(trimethylsilyl)silane: trapping of sisyl radicals

The photolysis of tris(trimethylsilyl)silane (TTMSS) was studied in the abs ence and in the presence of added trapping agents such as alkenes and alcoh ols. It was found that, unlike the case with pyrolysis, silyl radicals rath er than silylenes are produced. They may be efficiently trapped with alkene s, to give the hydrosilylation products, but not with alcohols. The major p roduct from the photolysis of TTMSS in the absence of added trapping agent (or with alcohols as trapping agents) was tetrakis(trimethylsilyl)silane. P ossible mechanisms to account for the photoproducts are presented.