A Cobalt-Containing Polysilane as an Effective Solid-State Catalyst for the Hydrosilylation of Alkenes

Abstract

A cobalt-containing polysilane was readily obtained from the treatment of poly(monohydro)silane with Co2(CO)8 at 60 °C. The resulting polysilane-supported cobalt catalyst (Co/Si catalyst) acts as a solid-state catalyst that exhibits good catalytic performance toward the hydrosilylation of various alkenes with hydrosiloxanes, such as 1,1,1,3,3-pentamethyldisiloxane. Suitable alkenes for this catalysis include functionalized alkenes such as allyl glycidyl ether and vinylsiloxanes as well as multiply functionalized alkenes such as triallylisocyanurate. The Co/Si catalyst can be recycled multiple times, and recycling is accomplished by simple centrifugation. It is noteworthy that this Co/Si system also catalyzes the modification of a silicone fluid and cross-linking between poly(monohydro)siloxanes and polysiloxanes that bear vinyl functionalities to afford silicone polymers, which are industrially important reactions.

Palladium-Catalyzed Cross-Coupling Polymerization of Bis-N-tosylhydrazones and Bis(silyl) Aryls: A New Access to Polycarbosilane Synthesis

“…The development of novel polymerization methods and related processes is of great importance in enriching the diversity of polymer science and accessing various functional materials. − As one of the most important families of functional materials, organosilicon polymers have been widely applied in adhesives, coatings, ceramics, moldings, and sealing materials. − In particular, polycarbosilanes containing Si–C bonds in polymer backbones have received extensive investigation due to their low toxicity, high chain flexibility, and excellent thermal and oxidative resistance. ,− The catalytic synthesis of polycarbosilanes traditionally relies on the hydrosilylation polymerization of alkenes and silanes, typically by Pt-based catalysts such as Speier’s and Karstedt’s catalysts. − More recently, rare earth metal catalysis, early transition-metal catalysis, , borane-based catalysis, , and photocatalysis , have emerged as new tools (Scheme a). In contrast to widely investigated hydrosilylation polymerization of alkenes, in which regioselectivity issues should be taken into consideration, other strategies are much less exploited and developed …”