Tris(N-pyrrolidinyl)phosphine substituted diiron dithiolate related to iron-only hydrogenase active site: Synthesis, characterization and electrochemical properties

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• 作者：Jun Hou ; Xiaojun Peng ; Zhiyou Zhou ; Shigang Sun ; Xing Zhao and Shang Gao
• 关键词：Bioinorganic chemistry ; Fe-only hydrogenase ; Spectroelectrochemistry ; Phosphine ligand
• 刊名：Journal of Organometallic Chemistry
• 出版年：2006
• 出版时间：1 November 2006
• 年：2006
• 卷：691
• 期：22
• 页码：4633-4640
• 全文大小：395 K

文摘

A tris(N-pyrrolidinyl)phosphine (P(NC₄H₈)₃) monosubstituted complex, [(μ-pdt)Fe₂(CO)₅P(NC₄H₈)₃] (2) was synthesized as a functional model of the hydrogen-producing capability of the iron hydrogenase active site. The structure was fully characterized by X-ray crystallography. IR and electrochemical studies have indicated that the P(NC₄H₈)₃ ligand has better electron-donating ability than that of those phosphine ligands, such as PMe₃, PTA (1,3,5-triaza-7-phosphaadamantane), PMe₂Ph PPh₃, and P(OEt)₃. The electrocatalytic activity of 2 was recorded in CH₃CN in the absence and presence of weak acid, HOAc. The cathodic shift of potential at −1.98 V and the dependence of current on acid concentration have indicated that complex 2 can catalyze the reduction of protons to hydrogen at its Fe⁰Fe^I level in the presence of HOAc. IR spectroelectrochemical experiments are conducted during the reduction of 2 under nitrogen and carbon monoxide, respectively. The formation of a bridging CO group during the reduction of 2 at −1.98 V has been identified using IR spectroelectrochemical techniques, and an electrocatalytic mechanism of 2 consistent with the spectroscopic and electrochemical results is proposed.