Vinyl-type polymerization of norbornene by a nickel-based catalyst with phosphoraneiminato ligands

High molecular weight vinyl-type polynorbornene was obtained in high yields with a highly active nickel-based phosphoraneiminato complex in the presen ce of methylaluminoxane. This polynorbornene is soluble at room temperature in chlorobenzene and shows no indication of crystallinity in the solid sta te. Catalyst activity, polymer yield, and polymer molecular weight can be c ontrolled over a wide range by variation of reaction parameters.