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

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.