Anionic Ring-Opening Polymerization of 1,2,2-Trimethyl-1-phenyl-1,2-disilacyclopentane

Abstract

The anionic ring-opening polymerization of 1,2,2-trimethyl-1-phenyl-1,2-disilacyclopentane took place in THF at 0∼−78°C. The initiators were nBu4NF, PhMe2SiK, and (PhMe2Si)2Cu(CN)Li2. When PhMe2SiK was used, the addition of HMPA was required for the polymerization. The polymerization initiated with (PhMe2Si)2Cu(CN)Li2 showed a living character to some extent. The product polymers contained not only a head-to-tail structure but also head-to-head and tail-to-tail structures, whose amounts were dependent on the initiator: 4% (nBu4NF), 30% (PhMe2SiK), and 12% ((PhMe2Si)2Cu(CN)Li2). These values reflect the efficiency of the phenyl group to stabilize the silyl anion that is the propagating end.