Regioselective propylene dimerization by tetrahedral (imino)pyridine Co^II dichloride complexes activated by MAO

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• 作者：Claudio Bianchini ; Giuliano Giambastiani ; Itzel Guerrero Rios ; Andrea Meli ; Anna M. Segarra ; Aless ; ro Toti ; Francesco Vizza
• 关键词：Oligomerization ; Propene ; Regioselectivity ; Cobalt ; (Imino)pyridine ligands
• 刊名：Journal of Molecular Catalysis A: Chemical
• 出版年：2007
• 出版时间：16 November 2007
• 年：2007
• 卷：277
• 期：1-2
• 页码：40-46
• 全文大小：183 K

文摘

On activation by MAO, tetrahedral Co^II dichloride complexes supported by 6-organyl-2-(imino)pyridine ligands generate active catalysts for the dimerisation of propylene to hexenes. The nature of the substituent on the 6-position of the pyridine ring influences both the selectivity and activity of the catalysts. The 6-thienyl complexes CoCl₂N₂^2Th and CoCl₂N₂^2BT dimerise propylene prevalently to linear hexenes through a propagation pathway involving 1,2-insertion into Co-H, followed by 2,1-insertion and β-hydride elimination. The 6-phenyl complex CoCl₂N₂^Ph is much less active and selective producing linear hexenes and methyl branched pentenes in comparable yields. The same activity trend and selectivity is observed for the dimerisation of 1-hexene, which however is one order of magnitude slower as compared to the dimerisation of propylene.