A UNIQUE STRUCTURE OF POLY(BENZYLDIMETHYLVINYLSILANE) BY ISOMERIZATION POLYMERIZATION

The anionic polymerization of benzyldimethylvinylsilane (BDMVS) was revealed to be accompanied by the isomerization reaction, which takes place regularly, once per two vinyl addition reactions. In the polymerizations of BDMVS, all polymers that were obtained both in the absence and presence of N,N,N',N'-tetramethylethylenediamine, both at 40-degrees-C and at 60-degrees-C, had the same spectra of IR, H-1 NMR, and C-13 NMR. The analyses of H-1 NMR and C-13 NMR certified the strictly regular isomerization. Owing to this isomerization, the polymer has a unique structure where silicon atoms are incorporated both in the backbone and in the pendant groups. This structure was supported by a decomposition experiment of the polymer. The six-membered ring structure, where the silylmethine anion of a propagating end and a benzylic proton in a penultimate unit exist adjacently, is considered to contribute to the isomerization, in collaboration with the high acidity of the benzylic protons.