Transition Metal-Catalyzed Synthesis of Silicon Polymers

Si–H and Si–Si bonds are efficiently transformed by early and late transition metal catalyses that involve possible key elemental steps, such as σ-bond metathesis, the oxidative addition of Si–H and Si–Si bonds, insertion of unsaturated compounds into silylmetals, the reductive elimination of Si–Si and Si–C bonds, and silylene generation via α-substituent migration in silylmetal species. These catalyses have enabled us to develop a dehydrogenative poly/oligosilane formation from hydrosilanes, oligosilane formation via a redistribution of hydrodisilanes, silylene-phenylene polymer synthesis via a redistribution of bis(trihydrosilyl)benzene, and (step-)ladder polycarbosilane synthesis by a dehydrogenative double silylation of diynes with a tetrakis(hydrosilyl)benzene. Insertion of unsaturated compounds (acetylenes, quinones, etc.) into Si–Si bonds of polymer backbones provides a new methodology for the modification/synthesis of silicon polymers. Cyclooligosilanes and cyclic disilanes undergo ring-opening copolymerization with p-quinones to give silylene and arylenedioxy unit-containing polymers. Other relevant processes as well as some chemical and physicochemical properties (ceramization, electric conductivity, thermal stability, etc.) of the resulting polymers are also described.