A Well-Defined Ni(II) α-Diimine Catalyst Supported on Sulfated Zirconia for Polymerization Catalysis

Abstract

The reaction of (α-diimine)NiMe2 (α-diimine = (2,6-iPr2-C6H3)N═CMeMeC═N(2,6-iPr2-C6H3)) with partially dehydroxylated sulfated zirconia (SZO300) in MeCN results in the formation of [(α-diimine)NiMe(NCMe)][SZO300] ([1][SZO300]) and methane. Reactions in Et2O resulted in mixtures of [(α-diimine)NiMe(OEt2)][SZO300] ([2][SZO300]) and [(α-diimine)NiMe(OEt2)][MeSZO300] ([2][MeSZO300]), which were characterized by solid-state NMR spectroscopy. Contacting these solids with ethylene and monitoring the reaction by solid-state NMR showed that Ni–Me sites insert ethylene. [1][SZO300] and [2][SZO300]/[2][MeSZO300] are active ethylene polymerization catalysts and show properties similar to those of closely related homogeneous catalysts. [2][SZO300]/[2][MeSZO300] copolymerizes ethylene and methyl 10-undecenoate to form copolymers with up to 0.4% incorporation of the polar monomer.