Nickel(II) Complexes Chelated by 2-Arylimino-6-benzoxazolylpyridine: Syntheses, Characterization, and Ethylene Oligomerization

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• 作者：Rong Gao ; Min Zhang ; Tongling Liang ; Fosong Wang ; Wen-Hua Sun
• 刊名：Organometallics
• 出版年：2008
• 出版时间：November 10, 2008
• 年：2008
• 卷：27
• 期：21
• 页码：5641-5648
• 全文大小：210K
• 年卷期：v.27,no.21(November 10, 2008)
• ISSN：1520-6041

文摘

2-(2-Benzoxazolyl)-6-(1-(arylimino)-ethyl)pyridines (L) were designed as ligands, and their nickel complexes LNiX₂ (X = Cl, 1a−7a; X = Br, 1b−7b) were formed. All ligands were fully characterized by NMR, FT-IR spectra, and elemental analyses, while the nickel complexes were examined by FT-IR spectra and elemental analyses. The molecular structures of nickel complexes were established by single-crystal X-ray diffraction. Complex 6a possesses coordination number 6 by coordination of one ligand, two moles of methanol, and one chloride anion, whereas complexes 1b and 5b possess coordination number 5 with distinct distortions, for 1b toward trigonal-bipyramidal geometry and for 5b toward square-pyramidal geometry. The nickel complex 1a was evaluated in the catalytic oligomerization of ethylene with different alkylaluminums as cocatalysts, and diethylaluminum chloride (Et₂AlCl) proved to be the most effective. Upon activation with Et₂AlCl, all nickel complexes showed outstanding thermal stability and good catalytic activity toward ethylene dimerization with high selectivity for α-C₄.