Anionic Ring-Opening Polymerization of 1,2,3,4-Tetramethyl-1,2,3,4-Tetraphenylcyclotetrasilane

摘要

Anionic ring opening polymerization of a mixture of stereoisomers of 1,2,3,4-tetramethyl-1,2,3,4-tetraphenylcyclotetrasilane provides poly(methylphenylsilylene) with molecular weights up to M=100,000. Strained monomers are prepared from octaphenylcyclotetrasilane by substitution of four phenyl groups with triflate groups using triflic acid and displacement of triflate groups by methyl substituents using methylmagnesium bromide. Anionic polymerization was initiated by butyl lithium and silyl potassium initiators with and without cryptands. Strong solvent effects on polymerization and subsequent cyclization were observed.