Enhanced Photochemical Hydrogen Production by a Molecular Diiron Catalyst Incorporated into a Metal鈥揙rganic Framework

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• 作者：Sonja Pullen ; Honghan Fei ; Andreas Orthaber ; Seth M. Cohen ; Sascha Ott
• 刊名：Journal of the American Chemical Society
• 出版年：2013
• 出版时间：November 13, 2013
• 年：2013
• 卷：135
• 期：45
• 页码：16997-17003
• 全文大小：391K
• 年卷期：v.135,no.45(November 13, 2013)
• ISSN：1520-5126

文摘

A molecular proton reduction catalyst [FeFe](dcbdt)(CO)₆ (1, dcbdt = 1,4-dicarboxylbenzene-2,3-dithiolate) with structural similarities to [FeFe]-hydrogenase active sites has been incorporated into a highly robust Zr(IV)-based metal鈥搊rganic framework (MOF) by postsynthetic exchange (PSE). The PSE protocol is crucial as direct solvothermal synthesis fails to produce the functionalized MOF. The molecular integrity of the organometallic site within the MOF is demonstrated by a variety of techniques, including X-ray absorption spectroscopy. In conjunction with [Ru(bpy)₃]²⁺ as a photosensitizer and ascorbate as an electron donor, MOF-[FeFe](dcbdt)(CO)₆ catalyzes photochemical hydrogen evolution in water at pH 5. The immobilized catalyst shows substantially improved initial rates and overall hydrogen production when compared to a reference system of complex 1 in solution. Improved catalytic performance is ascribed to structural stabilization of the complex when incorporated in the MOF as well as the protection of reduced catalysts 1^{鈥?/sup> and 12鈥?/sup> from undesirable charge recombination with oxidized ascorbate.}