Chromium Complexes with N,N,N-Tridentate Quinolinyl Anilido-Imine Ligand: Synthesis, Characterization, and Catalysis in Ethylene Polymerization

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• 作者：Zhiqiang Hao ; Bin Xu ; Wei Gao ; Yuxi Han ; Guang Zeng ; Jingshun Zhang ; Guanghua Li ; Ying Mu
• 刊名：Organometallics
• 出版年：2015
• 出版时间：June 22, 2015
• 年：2015
• 卷：34
• 期：12
• 页码：2783-2790
• 全文大小：485K
• ISSN：1520-6041

文摘

The treatment of 2-(ArN鈺怌H)C₆H₄-HNC₉H₆N ([N_QN_AN_I^Me]H, Ar = 2,6-Me₂C₆H₃; [N_QN_AN_I^Et]H, Ar = 2,6-Et₂C₆H₃; [N_QN_AN_I^iPr]H, Ar = 2,6-ⁱPr₂C₆H₃) with ⁿBuLi and CrCl₃(THF)₃ achieves the hetero-dinuclear complexes [N_QN_AN_I^R]CrCl(渭-Cl)₂Li(THF)₂ (1a, R = Me; 1b, R = Et; 1c, R = ⁱPr) or bisligated complex 魏⁵-[N_QN_AN_I^iPr]₂CrCl (2c) depending on the reactant ratios used. Reactions of these ligands with ⁿBuLi and CrCl₂(THF)₂ could achieve the square-pyramidal complexes [N_QN_AN_I^R]CrCl(THF) (3b, R = Et; 3c, R = ⁱPr). Complex 3c can be oxidized by alkyl chloride to dimeric complex {[N_QN_AN_I^iPr]CrCl}₂(渭-Cl)₂ (4) through a single-electron-transfer mechanism. Similar reaction of 2-(C₉H₆N)N鈺怌HC₆H₄-HNAr ([N_QN_IN_A^Me]H, Ar = 2,6-Me₂C₆H₃; [N_QN_IN_A^Et]H, Ar = 2,6-Et₂C₆H₃; [N_QN_IN_A^iPr]H, Ar = 2,6-ⁱPr₂C₆H₃) with ⁿBuLi and CrCl₃(THF)₃ furnishes [N_QN_IN_A^R]CrCl(渭-Cl)₂Li(THF)₂ (5a, R = Me; 5b, R = Et; 5c, R = ⁱPr) in high yields. However, a chromium complex with a butyl-substituted ligand, [N_Q^BuN_IN_A^iPr]CrCl₂ (6), is obtained when 2 equiv of ⁿBuLi is used. The molecular structures of 1c, 2c, 3c, 4, 5c, and 6 are confirmed by X-ray crystallography. Upon activation with MAO, the Cr(III) complexes (1a鈥?b>1c, 4, and 5a鈥?b>5c) show moderate catalytic activities (50 to 218 kg of PE路mol(Cr)^鈭?路h^鈥?) in ethylene polymerization, whereas the Cr(II) complexes 2c, 3b, and 3c are inert under the same conditions.