Synthesis, Characterization and Ethylene Oligomerization Studies of Nickel Complexes Bearing 2-Benzimidazolylpyridine Derivatives

A series of nickel complexes ligated by 2-(2-benzimidazole)-6-methylpyridine, 2-(1-methyl-2-benzimidazole)-6-acetylpyridine, and 2-(1-methyl-2-benzimidazole)-6-(1-aryliminoethyl)pyridine was
synthesized and examined by IR spectroscopic and elemental analysis. Their molecular structures were
determined by single-crystal X-ray diffraction analysis. On activation with diethylaluminum chloride
(Et2AlCl), all the nickel complexes exhibited good catalytic activities for ethylene oligomerization, and
the nickel(II) complexes bearing 2-(1-methyl-2-benzimidazole)-6-(1-aryliminoethyl)pyridines showed good
activities up to 5.87 × 105 g mol-1(Ni) h-1 atm-1. The various reaction parameters were investigated in
detail, and the results revealed that both the steric and electronic effects of ligands strongly affect the
catalytic activities of their nickel complexes as well as different coordination style.