Palladium and nickel complexes of (P,N)-ligands based on quinolines: Catalytic activity for polymerization and oligomerization

Four (P,N)-ligands (1–4) with different steric and electronic properties were synthesized. They were used to prepare the monocationic palladium complexes [Pd(P,N)(CH3)(NCCH3)](PF6) (9–12). The structures of the newly prepared ligand 3 and the neutral palladium complex [Pd(P,N)(CH3)Cl] (10) were analysed by X-ray. The catalytic activity of the palladium complexes toward the copolymerization of styrene and ethylene with CO was low or non-existent. The nickel complexes [Ni(P,N)(1-naphthyl)Cl] (13–16), modified with the ligands 1–4, were prepared and their catalytic activity toward ethylene oligomerization was studied. They showed high activity at ambient temperature and low ethylene pressure (1–12 bar) in the presence of MAO.