Bis(N-acylated imidazolin-2-imine) nickel catalyzed norbornene copolymerization with methyl acrylate

Abstract

The incorporation of even a small number of polar functional groups in the polyolefin backbone is sufficient to improve the polyolefin properties. Compared with palladium catalyzed direct copolymerization of olefins with polar vinyl monomers, the development of low-cost nickel-based catalysts is more challenging because of their higher oxophilicity. On the basis of the advantage of reducing the electrophilicity of the nickel center by the installation of strongly electron-donating ligands, we herein report the synthesis of novel bis(N-acylated imidazolin-2-imine) nickel complexes for norbornene polymerization and copolymerization with polar monomers. Moreover, the phenyl substituent on the imidazoline ligand is expected to enhance the tolerance of the nickel catalyst toward polar functional groups, thus allowing the copolymerization of norbornene with commercial methyl acrylate to afford high molecular weight functionalized cyclic olefin copolymers (COCs) with moderate activity and reasonable comonomer content.