Models for the Active Site in [FeFe] Hydrogenase with Iron-Bound Ligands Derived from Bis-, Tris-, and Tetrakis(mercaptomethyl)silanes
Models for the Active Site in [FeFe] Hydrogenase with Iron-Bound Ligands Derived from Bis-, Tris-, and Tetrakis(mercaptomethyl)silanes
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DOI：
10.1021/ic101399k
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发表时间：
2010-11-01
影响因子：
4.6
通讯作者：
Weigand, Wolfgang
中科院分区：
文献类型：
--
作者：
Apfel, Ulf-Peter;Troegel, Dennis;Weigand, Wolfgang
以相应的(氯甲基)硅烷为原料，合成了一系列通式为RnSi(CH2SH)(4-n)(n=0-2；R=有机基)的多官能团(硫甲基)硅烷。它们被用作多齿配体，用于将十二碳酰基三铁，Fe-3(CO)(12)转化为铁的羰基络合物，其中去质子化的(硫代甲基)硅烷作为p-桥联配体。这些络合物可作为[FeFe]氢酶的模型。其结构经元素分析(C，H，S)、核磁共振波谱(H-1，C-13，Si-29)和单晶X-射线衍射法进行了表征。用循环伏安法研究了它们的电化学性质，揭示了这些化合物催化生成二氢的新机理，即在催化循环中一个硫原子被质子化。三齿配体MESI(CH2SH)(3)与Fe-3(CO)(12)反应生成四核簇合物。X-射线衍射、电化学、拉曼、穆斯堡尔谱和磁化率研究表明，该化合物初步形成了[Fe2{Mu-Mesi(CH2S)(2)CH2SH}(CO)(6)]。然而，这种双核配合物慢慢地转变为四核物种[Fe-4{Mu-Mesi(CH2S)(3)}(2)(CO)(8)]。
A series of multifunctional (mercaptomethyl)silanes of the general formula type RnSi(CH2SH)(4-n)(n = 0-2; R = organyl) was synthesized, starting from the corresponding (chloromethyl)silanes. They were used as multidentate ligands for the conversion of dodecacarbonyltriiron, Fe-3(CO)(12), into iron carbonyl complexes in which the deprotonated (mercaptomethyl)silanes act as p-bridging ligands. These complexes can be regarded as models for the [FeFe] hydrogenase. They were characterized by elemental analyses (C, H, S), NMR spectroscopic studies (H-1, C-13, Si-29), and single-crystal X-ray diffraction. Their electrochemical properties were investigated by cyclic voltammetry to disclose a new mechanism for the formation of dihydrogen catalyzed by these compounds, whereby one sulfur atom was protonated in the catalytic cycle. The reaction of the tridentate ligand MeSi(CH2SH)(3)with Fe-3(CO)(12) yielded a tetranuclear cluster compound. A detailed investigation by X-ray diffraction, electrochemical, Raman, Mossbauer, and susceptibility techniques indicates that for this compound initially [Fe2{mu-MeSi(CH2S)(2)CH2SH} (CO)(6)] is formed. This dinuclear complex, however, is slowly transformed into the tetranuclear species [Fe-4{mu-MeSi(CH2S)(3)}(2)(CO)(8)].