Nonalternating Ethylene/Carbon Monoxide Copolymerization by a Bimetallic Phosphine Phenolate Ni(II) Catalyst

Nonalternating Ni(II)-catalyzed copolymerization of ethylene and carbon monoxide enables access to keto-functionalized polyethylenes but is challenged by strong CO binding and chain-growth inhibition by incorporated ketone groups. Here, we report a bimetallic bis(phosphine phenolate) Ni(II) complex based on a BINOL framework with a P-bound 2′,6′-dimethoxy-1,1′-biphenyl substituent, alongside a monometallic analogue. Both complexes are active catalysts, producing high-molecular-weight keto-polyethylenes with predominantly isolated ketone units. Notably, the bimetallic system can afford higher molecular weights under identical conditions, which we attribute tentatively to the increased steric bulk provided by the second metal center.