Copolymerization of olefins with polar monomers by transition metal catalysts

The investigation into copolymerizing olefins by Ni(Il) complexes bearing pyridylimine ligands was achieved in this study. The complexes, in the presence of a proper activating agent, were found to generate active catalysts for the ethylene-methyl acrylate copolymerization leading to hyperbranched copolymers with the polar monomer inserted in a variety of modes. The nature of the pyridylimine ligand determines catalyst activity, polymer molecular weight, and content of inserted MA. The ligand nature does not affect the manner of incorporation of MA that is dictated by both the activating agent and the solvent used to dissolve the nickel precatalyst: selective in-chain MA insertion occurs when the activator is AlEt 2 Cl and the precatalyst is dissolved in o-dichlorobenzene, while a variety of insertion modes occur in the presence of dichloromethane or AlMe 3 /BC 6 F 5) 3 /[Ph 3 C][B(C 6 F 5) 4 ] cocatalyst. On the other hand we have tested other types of nickel complexes containing 2-(arylimino)ethyl)pyridine for copolymerizing of ethylene with methyl acrylate. In all cases the complexes obtained solid polymers with different amounts of methyl acrylate incorporation based on substituents containing electron-donating or electron-withdrawing. For those ones with electron-donating, the amount of obtained copolymer is significantly more than those having electron withdrawing substituehts. [edited by Author]