Transition metal complexes of selected monoanionic phosphine ligands,
which also contain a selected Group 15 or 16 (IUPAC) element and which are coordinated
to a Group 3 to 11 (IUPAC) transition metal or a lanthanide metal, are polymerization
catalysts for the (co)polymerization of olefins such as ethylene and -olefins,
and the copolymerization of such olefins with polar group-containing olefins. These
and other nickel complexes of neutral and monoanionic bidentate ligands copolymerize
ethylene and polar comonomers, especially acrylates, at relatively high ethylene
pressures and surprisingly high temperatures, and give good incorporation of the
polar comonomers and good polymer productivity. These copolymers are often unique
structures, which are described.
