Zwitterionic Nickel(II) Catalyst for CO–Ethylene Alternating Copolymerization

A zwitterionic nickel­(II) catalyst has been discovered to display an initial catalytic activity comparable to that of cationic palladium catalysts for alternating copolymerization of carbon monoxide and ethylene. This demonstrates the absence of a severe dormant state in the present zwitterionic system, in contrast to the cationic nickel­(II) catalysts. However, the highly active catalyst is short-lived. Stoichiometric decomposition of the catalyst under carbon monoxide suggests that the insufficient stability of the tetraphenylborate motif in the ligand framework with respect to electrophilic attack is likely a culprit for catalyst deactivation.