Polymerization of monomers containing functional silyl groups. 13. Anionic polymerization of 2-[(N,N-dialkylamino)dimethylsilyl]-1,3-butadiene derivatives

Four 2-[(N,N-dialkylamino)silyl] substituted 1,3-butadiene derivatives, 2-[(N,N-diethylamino)dimethylsilyl]-1,3-butadiene (1), 2-[(N,N-dibutylamino)dimethylsilyl]-1,3-butadiene (2), 2-[(1-pyrrolidinyl) dimethylsilyl]-1,3-butadiene (3), and 2-[[N-[2'-(N',N'-dimethylamino)ethyl]-N-methylamino]dimethylsilyl]-1,3-butadiene (4), were newly synthesized and polymerized under various conditions of anionic polymerization. Under the condition of THF at -78 degrees C, all the monomers, 1-4, underwent living polymerization to afford the polymers of predictable molecular weights and narrow molecular weight distributions. On the other hand, side reactions occurred to some extent in the polymerizations of 1-4 carried out in heptane at 40 degrees C, although yields of polymers were quantitative in all cases within 1 h. The polymers obtained in THF consisted mainly of 1,4 (83-91%) and 1,2 (9-17%) linkages, while all the polymers obtained in heptane were structurally pure 1,4-addition products. There were mixtures of 1,4-E (16-32%) and 1,4-Z (68-84%) structures in the polymers of 1-3. The polymer of 4 was found to have a structure of exclusively 1,4-E unit.