Preparation of a diethynyl hypervalent silicon monomer by coordination-selective cleavage: structure and polymerization to give novel polycarbosilanes containing main-chain hexacoordinate silicon

Abstract

The hexacoordinate monomer R₂Si(CCH)₂[R = 8-(dimethylamino)naphthyl; the X-ray crystal structure showing both nitrogens trans to the ethynyl groups], formed from R₂Si(CCSiMe₃)₂ by coordination-selective cleavage of the trimethylsilyl–acetylene bonds in the presence of Buⁿ₄NF, undergoes palladium-catalysed cross-coupling polymerization with dihaloarenes to afford novel polycarbosilanes [R₂SiCCArCC]_n(Ar = 1,4-pnenylene, 4,4′-biphenylene, 9,10-anthrylene) containing hexacoordinate silicon.