Ethylene polymerization by salicylaldimine Nickel(II) complexes derived from arylnaphthylamine

A series of salicylaldimine ligands 2-tert-butyl-6-((2,4-bis(diphenylmethyl)-8-arylnaphthalen)imine)-phenol ( L1 : Aryl =4- t Bu-phenyl; L2 : Aryl = p-tolyl; L3 : Aryl = phenyl; L4 : 4-CF 3 -phenyl) and the corresponding neutral salicylaldimine nickel complexes ( Ni1 - Ni4 ) were prepared and characterized. In ethylene polymerization at 20 °C, these nickel complexes are highly active, with activities of up to 6.88 × 10 5  g·mol −1 ·h −1 . Moreover, the molecular weight of the polyethylene could reach up to 8.1 × 10 5 . Comparing with the classic salicylaldimine nickel complexes Ni5 at 20 °C, complexes Ni1 with the 4- t Bu-phenyl substituent demonstrated 8 times higher activity and 35 times higher polyethylene molecular weight. Graphical abstract