Zirconium and hafnium complexes with new tetra-azane ligands: Synthesis, characterization and catalytic properties for ethylene polymerization

Zirconium and hafnium complexes bearing new tetra-azane ligands, {1,2-[(2′-(ArN)C6H4HCN)]2C6H4}MCl2, were synthesized in high yields and studied as ethylene polymerization catalysts to form ultra-high molecular weight polyethylene.60