Reusable Oxidation Catalysis Using Metal-Monocatecholato Species in a Robust Metal鈥揙rganic Framework

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• 作者：Honghan Fei ; JaeWook Shin ; Ying Shirley Meng ; Mario Adelhardt ; J枚rg Sutter ; Karsten Meyer ; Seth M. Cohen
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：April 2, 2014
• 年：2014
• 卷：136
• 期：13
• 页码：4965-4973
• 全文大小：483K
• 年卷期：v.136,no.13(April 2, 2014)
• ISSN：1520-5126

文摘

An isolated metal-monocatecholato moiety has been achieved in a highly robust metal鈥搊rganic framework (MOF) by two fundamentally different postsynthetic strategies: postsynthetic deprotection (PSD) and postsynthetic exchange (PSE). Compared with PSD, PSE proved to be a more facile and efficient functionalization approach to access MOFs that could not be directly synthesized under solvothermal conditions. Metalation of the catechol functionality residing in the MOFs resulted in unprecedented Fe-monocatecholato and Cr-monocatecholato species, which were characterized by X-ray absorption spectroscopy, X-band electron paramagnetic resonance spectroscopy, and ⁵⁷Fe M枚ssbauer spectroscopy. The resulting materials are among the first examples of Zr(IV)-based UiO MOFs (UiO = University of Oslo) with coordinatively unsaturated active metal centers. Importantly, the Cr-metalated MOFs are active and efficient catalysts for the oxidation of alcohols to ketones using a wide range of substrates. Catalysis could be achieved with very low metal loadings (0.5鈥? mol %). Unlike zeolite-supported, Cr-exchange oxidation catalysts, the MOF-based catalysts reported here are completely recyclable and reusable, which may make them attractive catalysts for 鈥榞reen鈥?chemistry processes.