Metathesis copolymerization of norbornene with phenylacetylene and its ring-substituted derivatives catalysed by WCl 6: 1. Product characterization

Abstract

In the copolymerization of phenylacetylene (PA) with norbornene (NBE) catalysed by WCl 6, both monomers reacted simultaneously, the relative reaction rate of PA being several times higher than that of NBE. The product consisted of polymeric (84 wt%, M ̄ n =41 000 ) and oligomeric (16 wt%, M ̄ n = several hundreds ) parts. According to g.p.c., u.v. and n.m.r. analyses, the former part was a PA-NBE copolymer, while the latter was a mixture of PA oligomers. The PA-NBE dyads could be directly observed in the 2-D H-H COSY n.m.r. spectrum of the polymeric part. The p-CF 3 and o-CF 3 derivatives of PA showed reactivities close to that of NBE (relative rates ∼ 1.4:1 and ∼ 1.3:1, respectively). The oligomeric by-products were less in these systems, and the formation of copolymers was similarly confirmed.