CH Bond Activation of Methane by a Transient 畏2-Cyclopropene/Metallabicyclobutane Complex of Niobium

详细信息    查看全文

• 作者：Chen Li ; Chiara Dinoi ; Yannick Coppel ; Michel Etienne
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：October 7, 2015
• 年：2015
• 卷：137
• 期：39
• 页码：12450-12453
• 全文大小：344K
• ISSN：1520-5126

文摘

This study challenges the problem of the activation of a CH bond of methane by soluble transition metal complexes. High pressure solution NMR, isotopic labeling studies, and kinetic analyses of the degenerate exchange of methane in the methyl complex [Tp^Me2NbCH₃(c-C₃H₅)(MeCCMe)] (1) are reported. Stoichiometric methane activation by the mesitylene complex [Tp^Me2Nb(CH₂-3,5-C₆H₃Me₂)(c-C₃H₅) (MeCCMe)] (2) giving 1 is also realized. Evidence is provided that these reactions proceed via an intramolecular abstraction of a 尾-H of the cyclopropyl group to form either methane or mesitylene from 1 or 2, respectively, yielding the transient unsaturated 畏²-cyclopropene/metallabicyclobutane intermediate [Tp^Me2Nb(畏²-c-C₃H₄) (MeCCMe)] A. This is followed by its mechanistic reverse 1,3-CH bond addition of methane yielding the product.