Syntheses of iron, cobalt, chromium, copper and zinc complexes with bulky bis(imino)pyridyl ligands and their catalytic behaviors in ethylene polymerization and vinyl polymerization of norbornene

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• 作者：Jianxin Chen ; Yuanbiao Huang ; Zhongshui Li ; Zhichun Zhang ; Chunxia Wei ; Tingyan Lan and Wenjie Zhang
• 关键词：Ethylene and norbornene polymerization ; Bis(imino)pyridyl ligands ; Iron ; Cobalt ; Chromium ; Copper ; Zinc
• 刊名：Journal of Molecular Catalysis A: Chemical
• 出版年：2006
• 出版时间：15 November 2006
• 年：2006
• 卷：259
• 期：1-2
• 页码：133-141
• 全文大小：669 K

文摘

The syntheses, characterization, and ethylene and norbornene polymerization behaviors of iron, cobalt, chromium, copper and zinc complexes (3–7b) bearing chelating bulky 2,6-bis[1-(2,6-diisopropylphenylimino)ethyl]pyridine ligand (1) or 2,6-bis[1-(2,5-ditertbutylphenylimino)ethyl]pyridine ligand (2) are reported. X-ray diffraction study of the cobalt complex (4) shows the geometry of the cobalt center to be distorted trigonal bipyramid. Treatment of the iron, cobalt 2,6-bis[1-(2,5-ditertbutylphenylimino)ethyl pyridine complexes (3 and 4) with methylaluminoxane (MAO) lead to a highly active ethylene polymerization catalysts converting ethylene to highly linear polyethylene (PE), while the corresponding chromium complex (5) is disclosed as moderate catalytic activity for the polymerization of ethylene. The specific catalytic activities were evaluated at different temperature and Al/M (M = Fe, Co and Cr) ratio. In addition, the complexes 3–5 and corresponding compounds of FeCl₂, CoCl₂(THF)_1.5 and CrCl₃(THF)₃ can also catalyze vinyl polymerization of norbornene activated with MAO and show good activities. However, the copper and zinc complexes (6a–7b) showed no active in ethylene and norbornene polymerization in the presence of MAO.