Evidence for Metal鈥揝urface Interactions and Their Role in Stabilizing Well-Defined Immobilized Ru鈥揘HC Alkene Metathesis Catalysts

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• 作者：Manoja K. Samantaray ; Johan Alauzun ; David Gajan ; Santosh Kavitake ; Ahmad Mehdi ; Laurent Veyre ; Moreno Lelli ; Anne Lesage ; Lyndon Emsley ; Christophe Cop茅ret ; Chlo茅 Thieuleux
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：February 27, 2013
• 年：2013
• 卷：135
• 期：8
• 页码：3193-3199
• 全文大小：403K
• 年卷期：v.135,no.8(February 27, 2013)
• ISSN：1520-5126

文摘

Secondary interactions are demonstrated to direct the stability of well-defined Ru鈥揘HC-based heterogeneous alkene metathesis catalysts. By providing key stabilization of the active sites, higher catalytic performance is achieved. Specifically, they can be described as interactions between the metal center (active site) and the surface functionality of the support, and they have been detected by surface-enhanced ¹H鈥?sup>29Si NMR spectroscopy of the ligand and ³¹P solid-state NMR of the catalyst precursor. They are present only when the metal center is attached to the surface via a flexible linker (a propyl group), which allows the active site to either react with the substrate or relax, reversibly, to the surface, thus providing stability. In contrast, the use of a rigid linker (here mesitylphenyl) leads to a well-defined active site far away from the surface, stabilized only by a phosphine ligand which under reaction conditions leaves probably irreversibly, leading to faster decomposition and deactivation of the catalysts.