Chelating N-heterocyclic carbene group IV complexes for the polymerization of ethylene and styrene

Chelating N-heterocyclic carbene zirconium and titanium complexes, combined with MAO, have been employed in the polymerization of ethylene and styrene. These complexes have been designed to simulate the highly successful phenoxy-imine ligated, non-metallocene complexes developed by scientists at Mitsui. Investigations into the effects of metal center, pressure, temperature, and time on the polymerization of ethylene were carried out. Extremely high molecular weight polyethylene could be produced (approaching 1 million Da), with industrially desirable, broad molecular weight distributions. In the case of styrene polymerizations utilizing the titanium catalyst, highly syndiotactic polystyrene was produced.