Synthesis of TMS-Modified Polymethylenes

Significance

Polymerization of the ylide monomer derived from trimethylsilylmethyldimethylsulfonium iodide (1) provided a random copolymer (2) containing both trimethylsilylmethylidene and meth­ylidene groups with a ratio of 1.75. Such a composition cannot be achieved by the homopolymerization of vinyltrimethylsilane. The polymer was characterized by NMR spectroscopy, gel permeation chromatography as well as elemental analysis. A cationic polymerization initiated by trialkylsulfonium salt, [Me₂SCH₂SiMe₃]⁺[BF₃X]^-, is proposed as the reaction mechanism. The cationic nature of this polymerization is consistent with the observed broad polydispersities (PDI) of the resultant polymers, which also indicates that the polymerization is not a controlled/living process.