An Electronic Rationale for Observed Initiation Rates in Ruthenium-Mediated Olefin Metathesis: Charge Donation in Phosphine and N-Heterocyclic Carbene Ligands

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• 作者：Kendra Getty ; Mario Ulises Delgado-Jaime ; Pierre Kennepohl
• 刊名：Journal of the American Chemical Society
• 出版年：2007
• 出版时间：December 26, 2007
• 年：2007
• 卷：129
• 期：51
• 页码：15774 - 15776
• 全文大小：365K
• 年卷期：v.129,no.51(December 26, 2007)
• ISSN：1520-5126

文摘

Ru K-edge XAS data indicate that second generation ruthenium-based olefin metathesis precatalysts (L = N-heterocyclic carbene) possess a more electron-deficient metal center than in the corresponding first generation species (L = tricyclohexylphosphine). This surprising effect is also observed from DFT calculations and provides a simple rationale for the slow phosphine dissociation kinetics previously noted for second-generation metathesis precatalysts.