Aryl Phosphine Nickel(II) and Palladium(II) Complexes with N,O-Amino-carboxylate Chelate Ligands [(Aryl)(R3P)M(N,O-α-aminocarboxylate)](M = Ni, Pd). Catalysts for the Polymerization of Olefins

Abstract

The title complexes [(Aryl)(R3P)M(N,O-α-aminocarboxylate)] (M = Ni, Pd) were synthesized by reaction of [(o-tolyl)(Ph3P)2NiBr] or of [(p-Me3CC6H4)(o-tolyl3P)Pd(μ-Br)]2 with the anions of α-amino acids. The spectroscopic data indicate that the nickel complexes are formed as mixtures of isomers, whereas for the palladium complexes only one isomer is observed. The complex [(o-tolyl)(Ph3P)Ni(glycinate)] is – in the presence of AlEt3 – a highly active catalyst for the polymerization of ethylene [up to 1800 kg PE / (mol Ni·h)] and gives polymers with remarkably high molecular weights (up to 900.000 g/mol) and with few branchings.