Three diiron complexes bearing an aromatic ring as mimics of the diiron subunit of [FeFe]-hydrogenase: synthesis, electron transfer and coupled chemical reactions.
Three diiron complexes bearing an aromatic ring as mimics of the diiron subunit of [FeFe]-hydrogenase: synthesis, electron transfer and coupled chemical reactions.
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DOI：
10.1039/c2dt31083j
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发表时间：
2012-08
影响因子：
4
通讯作者：
Jia Zhao;Zhenhong Wei;Xianghua Zeng;Xiaoming Liu
中科院分区：
文献类型：
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作者：
Jia Zhao;Zhenhong Wei;Xianghua Zeng;Xiaoming Liu
在0.1mol L ~（-1）[NBut（4）]BF（4）-乙腈（MeCN）溶液中，在CO和Ar气氛下，研究了三种二铁配合物（1-Ph，2-OH和3-OCOFc）作为[FeFe]-氢化酶二铁亚基模拟物的电化学性质.配合物3-OCOFc由配合物2-OH与二茂铁酰氯（FcOCCl）反应制得。使用各种光谱技术充分表征了该复合物。用X-射线单晶衍射分析确定了其结构。除了已确立的ECE（E为电化学，C为化学）机理外，还揭示了在更负的电位下进一步可逆还原约。在CO气氛下观察到600 mV。电化学和红外光谱数据的分析表明，第二次氧化还原反应是由四铁团簇的双电子过程引起的。该产物由ECE过程产生的二价阴离子与其母体络合物（1-Ph、2-OH和3-OCOFc）之间的反应原位形成，并且被认为是核心“Fe（4）（II）"。该反应仅在CO存在时发生。在Ar气氛下，本体电解导致完全还原产物，即铁处于零氧化态，但络合物是例外。提出了一个描述CO气氛下电子转移和耦合化学反应的整体机理。
Three diiron complexes (1-Ph, 2-OH, and 3-OCOFc) as mimics of the diiron subunit of [FeFe]-hydrogenase were electrochemically investigated in 0.1 mol L(-1) [NBut(4)]BF(4)-acetonitrile (MeCN) under CO and Ar atmosphere. Complex 3-OCOFc was prepared from the reaction of complex 2-OH with ferrocenylacyl chloride (FcOCCl). The complex was fully characterised using a variety of spectroscopic techniques. Its structure was established using X-ray single crystal diffraction analysis. In addition to the well-established ECE (E for electrochemical and C for chemical) mechanism, it was revealed that a further reversible reduction at a potential more negative by ca. 600 mV was observed under CO atmosphere. It was further proposed based on the analysis of electrochemical and infrared spectroscopic data that the second redox was due to a two-electron process of supposedly a tetrairon cluster. This product was formed in situ from the reaction between the dianion generated from the ECE process and its parent complex (1-Ph, 2-OH, and 3-OCOFc) and is supposedly of a core "Fe(4)(II)". This reaction occurred only when CO was presented. Under Ar atmosphere, bulk electrolysis led to fully-reduced products, that is, with the iron at the oxidation state of zero, but complex was an exception. An overall mechanism to describe the electron transfer and coupled chemical reactions under CO atmosphere was proposed.