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.