Dimerization of Propylene by Nickel （II） and Cobalt （II） Catalysts Based on Bidentate Nitrogen-phosphino Chelating Ligands

The catalytic property of propylene dimerization by several nickel (II), cobalt (II) complexes containing N-P bidentate ligands was studied in combination with organoaluminum co-catalysts. The effects of the type of aluminum co-catalysts and its relative amount, the nature of precursors in terms of ligand backbone and metal center were investigated. The results indicated that precursor I (N,-N-dimethyl-2-(diphenylphosphino)aniline nickel (II) dichloride)exhibited high activity in propylene dimerization in the presence of the strong Lewis acid Et3A12Cl3, whereas low productivity by its cobalt analogues was observed under identical reaction conditions.