Nickel Catalyzed Copolymerization of Ethylene and Alkyl Acrylates

Ni­(II) complexes bearing an o-bis­(aryl)­phosphinophenolate
ligand were synthesized as catalysts for copolymerization of ethylene
and alkyl acrylates. When the P-bound aryl group was 2,6-dimethoxyphenyl
group, one of the oxygen atoms in the methoxy groups coordinated to
the nickel center on its apical position. This complex was a highly
active catalyst without any activators to give highly linear and high
molecular weight copolymers. The structures of the copolymers were
determined by 1H and 13C NMR to clarify that
the alkyl acrylate comonomers were incorporated in the main chain
and that the structures of the copolymers were significantly influenced
by the structure of the aryl group in the ligand.