New Reactions of Terminal Hydrides on a Diiron Dithiolate

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• 作者：Wenguang Wang ; Thomas B. Rauchfuss ; Lingyang Zhu ; Giuseppe Zampella
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：April 16, 2014
• 年：2014
• 卷：136
• 期：15
• 页码：5773-5782
• 全文大小：600K
• 年卷期：v.136,no.15(April 16, 2014)
• ISSN：1520-5126

文摘

Mechanisms for biological and bioinspired dihydrogen activation and production often invoke the intermediacy of diiron dithiolato dihydrides. The first example of such a Fe₂(SR)₂H₂ species is provided by the complex [(term-H)(渭-H)Fe₂(pdt)(CO)(dppv)₂] ([H1H]⁰). Spectroscopic and computational studies indicate that [H1H]⁰ contains both a bridging hydride and a terminal hydride, which, notably, occupies a basal site. The synthesis begins with [(渭-H)Fe₂(pdt)(CO)₂(dppv)₂]⁺ ([H1(CO)]⁺), which undergoes substitution to afford [(渭-H)Fe₂(pdt)(CO)(NCMe)(dppv)₂]⁺ ([H1(NCMe)]⁺). Upon treatment of [H1(NCMe)]⁺ with borohydride salts, the MeCN ligand is displaced to afford [H1H]⁰. DNMR (EXSY, SST) experiments on this complex show that the terminal and bridging hydride ligands interchange intramolecularly at a rate of 1 s^鈥? at 鈭?0 掳C. The compound reacts with D₂ to afford [D1D]⁰, but not mixed isotopomers such as [H1D]⁰. The dihydride undergoes oxidation with Fc⁺ under CO to give [1(CO)]⁺ and H₂. Protonation in MeCN solution gives [H1(NCMe)]⁺ and H₂. Carbonylation converts [H1H]⁰ into [1(CO)]⁰.