Electrochemical study of the role of a H-bridged, unsymmetrically disubstituted diiron complex in proton reduction catalysis

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• 作者：Salah Ezzaher ; Jean-Franç ; ois Capon ; Nicolas Dumontet ; Fré ; dé ; ric Gloaguen ; Franç ; ois Y. Pé ; tillon ; Philippe Schollhammer ; Jean Talarmin ; ^{jean.talarmin@univ-brest.fr}
• 关键词：Electrochemistry ; Di-iron complexes ; Bridging hydride ; Proton reduction ; Bioinorganic chemistry ; [FeFe]hydrogenases
• 刊名：Journal of Electroanalytical Chemistry
• 出版年：2009
• 出版时间：15 February 2009
• 年：2009
• 卷：626
• 期：1-2
• 页码：161-170
• 全文大小：1231 K

文摘

The electrochemical behaviour of the unsymmetrically disubstituted [Fe₂(CO)₄(¦Ê²-dppe)(¦Ì-pdt)(¦Ì-H)]⁺ (1¦ÌH⁺) complex was studied by cyclic voltammetry (CV) in MeCN?and CH₂Cl₂¨C[NBu₄][PF₆] both in the absence and in the presence of acid (HBF₄ ¡¤ Et₂O or HOTs). In the absence of acid, 1¦ÌH⁺ undergoes a reversible one-electron oxidation and two-successive one-electron reductions, the first of which is partially reversible. In contrast to symmetrical analogues, 1¦ÌH⁺ does not regenerate its neutral precursor 1 upon reduction on the CV timescale. When acid is present, the reduction leads to catalytic proton reduction at a mild potential (ca. ?.3 V vs. Fc⁺/Fc) according to an original mechanism where 1¦ÌH⁺ is the catalyst. A second proton reduction process at ?.5 V is also observed for both HBF₄ ¡¤ Et₂O and HOTs. The latter is proposed to be catalysed by the one-electron reduced form of the H-bridged complex, 1¦ÌH.