Synthesis of benzoxazolylpyridine nickel complexes and their efficient dimerization of ethylene to alpha-butene.
A series of new nickel complexes bearing benzoxazolylpyridines was synthesized and characterized by FT-IR spectroscopic and elemental analysis. The molecular structures of two representative complexes were determined by single-crystal X-ray diffraction. The complex [NiCl2[2-(2-benzoxazolyl)-6-methylpyridine]] (5) is a centrosymmetric dinuclear compound with two penta-coordinated Ni(II) centers, whereas the complex [NiCl2[2-(5-methyl-2-benzoxazolyl)-6-methylpyridine}] (6) is mononuclear exhibiting a distorted octahedral-coordination geometry around the nickel atom. Upon activation with diethylaluminium chloride (Et2AlCl), all the complexes exhibited moderate to good catalytic activity for ethylene oligomerization (27-415 g mmol(-1)(Ni) h(-1) bar(-1)) with high selectivity for ethylene dimerization to form alpha-butene. The observed variance in the catalytic activities of the complexes is attributed to the different ligand environments and effects of reaction parameters.
Key laboratory of Engineering Plastics and Beijing Natural Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
Rong
R
Gao
Liwei
L
Xiao
Xiang
X
Hao
Wen-Hua
WH
Sun
Fosong
F
Wang