Nickel and cobalt complexes bearing β-ketoamine ligands: syntheses, structures and catalytic behavior for norbornene polymerization

Late transition metal (nickel, cobalt) complexes (1, 2) with β-ketoamine ligand (L) based on the pyrazolone derivative are synthesized by condensing 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone with p-fluoroaniline, and then treating the β-ketoamine (L) produced with the respective metal halide. The bis(β-ketoamine)metal complexes can act as catalyst precursors for norbornene polymerization with activation by methylaluminoxane. The effects of the central metal variation in the complex on catalyst activities and polymer microstructure are described.