Polymerization of Ethylene with Cationic Palladium and Nickel Catalysts Containing Bulky Nonenolizable Imine−Phosphine Ligands

A number of bulky, nonenolizable Pd(II) and Ni(II) imine−phosphine complexes have been
synthesized and tested in the ethylene polymerization. These catalysts show improved
temperature stability with respect to the corresponding diimine complexes. Nickel imine−phosphine precatalysts containing gem-dimethyl substituent α to phosphorus display
moderate activity and produce substantially higher molecular weight polyethylene compared
to the corresponding enolizable complexes.