Phosphinobenzenamine Nickel Catalyzed Efficient Copolymerization of Methyl Acrylate with Ethylene and Norbornene

Abstract

A series of phosphinobenzenamine-based nickel complexes bearing substituted phenylphosphine ligands were synthesized and characterized. These nickel complexes combined with methylaluminoxane (MAO) exhibited very high activity (∼106 g mol–1 h–1) and good thermal stability for norbornene polymerization. The nickel catalysts were able to conduct copolymerization of norbornene and methyl acrylate (MA) with high activity (3.76 × 105 g mol–1 h–1) to give high-molecular-weight functionalized cyclic olefin copolymer (COC) with reasonable MA incorporation (2.39–6.47 mol %). Moreover, the nickel catalysts also promote the copolymerization of ethylene and MA with moderate activity (∼104 g mol–1 h–1) to produce semicrystalline high-molecular-weight polar functionalized polyethylene (PE). The MA incorporation in the copolymer was controlled in a wide range (up to 15.5 mol %). These complexes without any sterically bulky substituent on the ligand are distinctive examples of earth-abundant nickel complexes toward the direct copolymerization of ethylene or norbornene with the challenging vinyl polar monomer MA.