Single-Component α-Iminocarboxamide Nickel Ethylene Polymerization and Copolymerization Initiators

The reaction of Ni(COD)2, benzyl chloride, potassium N-(2,6-diisopropylphenyl)-2-(2,6-diisopropylphenylimino)propanamidate, and pyridine or 2,6-lutidine yields N,O-bound α-iminocarboxamide complexes that can be used as single-component initiators for the homopolymerization of ethylene or the copolymerization of ethylene with functionalized norbornene monomers. Comparison of the Py versus 2,6-lutidine complexes highlights how the nitrogen ligand lability influences polymerization activity. It is also possible to synthesize η1-CH2COPh complexes via these procedures, which are less stable to the presence of monomer functionalities.