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

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 (similar to 10(6) 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 x 10(5) 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 (similar to 10(4) 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.

Automated summary

A series of nickel complexes with substituted phenylphosphine ligands were synthesized and characterized. These complexes showed high activity and thermal stability in norbornene polymerization. They could also copolymerize norbornene and methyl acrylate to produce functionalized cyclic olefin copolymer, and copolymerize ethylene and methyl acrylate to produce polar functionalized polyethylene.