Synthesis of allylnickel complexes with phosphine sulfonate ligands and their application for olefin polymerization without activators

Phosphine sulfonate nickel complexes [(o-Ar₂- PC ₆SO₃)Ni(allyl)] (Ar = Ph, o-MeOC₆H₄) are prepared and used as catalysts for ethylene polymerization. The products were low molecular weight polyethylenes possessing only methyl branches. The activity for ethylene polymerization with the phenyl-substituted complex was comparable to that of o-methoxyphenyl-substituted complex in the absence of activator. Comparison with the corresponding allylpalladium complex revealed that the nickel catalysts produced polyethylenes with lower molecular weight and more branches than the palladium catalyst.