Synthesis, structural characterization and conversion of dinuclear iron–sulfur clusters containing the disulfide ligand: [Cp*Fe(μ–η2:η2-bdt)(cis-μ–η1:η1-S2)FeCp*], [Cp*Fe(μ-S(C6H4S2))(cis-μ–η1:η1-S2)FeCp*], and [{Cp*Fe(bdt)}2(trans-μ–η1:η1-S2)]
尽管固氮酶通常在环境温度和压力下将分子氮转化为氨,但该反应目前在工业上使用 Haber-Bosch 工艺进行,该工艺需要极端温度和压力来激活二氮。生物固定通过二氮和还原的 N x H y 发生含硫配体化合物的多铁中心的物种,但难以阐明机理细节并获得稳定的模型中间体配合物以供进一步研究。尽管大多数模型都涉及单核系统,但已应用基于金属的合成模型来揭示部分细节。在这里,我们报告了由二齿硫醇盐配体桥接的二铁络合物,可以容纳 HN = NH。在还原和质子化之后,HN=NH通过由 N 2 H 3 –和 NH 2 –桥接的关键中间复合物转化为 NH 3物种。值得注意的是,最终的氨释放受水作为质子源的影响。进行了密度泛函理论计算,提出了生物固氮途径。
[Cp*Fe(μ-bdt)(t-H)FeCp*][BF4] (2) and subsequent intramolecular isomerization to bridging hydride 3[BF4]. A one-electron reduction of 3[BF4] by CoCp2 affords a paramagnetic mixed-valent FeIIFeIII hydride complex, [Cp*Fe(μ-η2:η2-bdt)(μ-H)FeCp*] (4). Further, studies on protonation processes of diruthenium and iron–ruthenium analogues of 1, [Cp*M1(μ-bdt)M2Cp*] (M1 = M2 = Ru, 5; M1 = Fe, M2 = Ru, 8), provide experimental
Electronic Structure of Thiolate-bridged Diiron Complexes and a Single-electron Oxidation Reaction: A Combination of Experimental and Computational Studies
作者:Si Chen、Lun Luo、Yang Li、Dawei Yang、Jingping Qu、Yi Luo
DOI:10.1002/cjoc.201600262
日期:2016.9
lengths. The ground state of 1 is predicted to be two low‐spin ferrousions (SFe=0) and 2 has a medium‐spin ferricion (SFe=1/2) and a low‐spin ferrous center (SFe=0), and the oxidation of 1 to 2 is calculated to be a single‐metal‐based process. Both complexes have no significant antiferromagnetic coupling character.
presence of 1 equiv of tBuNC, the homolytic cleavage of the FeIII–H bond in the diiron terminal hydride complex [Cp*Fe(t-H)(μ-η2:η4-bdt)FeCp*][BF4] (1[BF4]) smoothly took place to release 1/2 H2, followed by binding of a tBuNC group to the unsaturated FeII center. Interestingly, upon exposure of 1[BF4] to 1 atm of acetylene, the isomerization process of the hydride ligand from the terminal to bridging coordination
在1个当量的存在吨BuNC,所述Fe的均裂III在二铁终端氢化物络合物-H键的[Cp *的Fe(吨-H)(μ-η 2:η 4 -bdt)FeCp *] [顺利发生BF 4 ](1 [BF 4 ])释放1/2 H 2,然后将t BuNC基团键合到不饱和Fe II中心。有趣的是,当1 [BF 4 ]暴露于1atm的乙炔时,氢化物配体从末端到桥联配位点的异构化过程不受影响。经过氢化二铁桥联配合物的处理2 [BF 4 ]与在30℃下乙炔,二铁III -H键被打破,然后乙炔分子被配位到中心二铁中一种新颖的μ-η 2:η 2侧上的方式。在上述反应体系中,无论是末端的还是桥连的氢化物配体均起着电子供体的作用,将二铁中心从Fe III Fe III还原为Fe III Fe II。这些反应模式让人想起负责N 2结合和H 2的重要E 4状态。在包含两个Fe–H–Fe}图案的固氮酶催化循环中解放,作为还原铁中心的电子库。不同地,当用TMSN
Spectroscopic and Quantum Chemical Investigation of Benzene-1,2-dithiolate-Coordinated Diiron Complexes with Relevance to Dinitrogen Activation
作者:Sabrina I. Kalläne、Anselm W. Hahn、Thomas Weyhermüller、Eckhard Bill、Frank Neese、Serena DeBeer、Maurice van Gastel
DOI:10.1021/acs.inorgchem.9b00177
日期:2019.4.15
iron atoms were found to be in a local low-spin configuration. When no additional X ligand is bound, the bdt ligand is tilted and features a stabilizing π-interaction with one of the iron atoms. The number of lone-pair orbitals provided by the nitrogen-containing species is crucial to the overall electronic structure. When only one lone-pair is present and the iron atoms are bridged by oneatom, a three-center
在这项工作中,苯-1,2-二硫醇(BDT)五甲基环戊二烯二-铁复合物的[Cp *的Fe(μ-η 2:η 4 -bdt)FeCp *]和其的[Cp *的Fe(BDT)(X) FeCp *]类似物(其中X = N 2 H 2,N 2 H 3 –,H –,NH 2 –,NHCH 3 –或NO +)通过光谱和计算研究进行了研究。这些络合物作为在固氮酶中激活二氮的模型系统具有相关性,并与它的活性位点共享铁,硫配体和非常灵活的电子结构的存在。基于X射线发射光谱(XES),X射线晶体学,穆斯堡尔(Mössbauer),NMR和EPR光谱的组合,已通过实验阐明了该系列的几何结构和电子结构。发现所有铁原子均处于局部低旋转构型。当没有另外的X配体结合时,bdt配体倾斜并且具有与铁原子之一的稳定的π-相互作用。含氮物质提供的孤对轨道的数量对于整个电子结构至关重要。当仅存在一个孤对且铁原子被一个原子桥接时,会出现
Ammonia formation by a thiolate-bridged diiron amide complex as a nitrogenase mimic
Haber–Bosch process, which requires extreme temperatures and pressures to activatedinitrogen. Biological fixation occurs through dinitrogen and reduced NxHy species at multi-iron centres of compounds bearing sulfur ligands, but it is difficult to elucidate the mechanistic details and to obtain stable model intermediate complexes for further investigation. Metal-based synthetic models have been applied
尽管固氮酶通常在环境温度和压力下将分子氮转化为氨,但该反应目前在工业上使用 Haber-Bosch 工艺进行,该工艺需要极端温度和压力来激活二氮。生物固定通过二氮和还原的 N x H y 发生含硫配体化合物的多铁中心的物种,但难以阐明机理细节并获得稳定的模型中间体配合物以供进一步研究。尽管大多数模型都涉及单核系统,但已应用基于金属的合成模型来揭示部分细节。在这里,我们报告了由二齿硫醇盐配体桥接的二铁络合物,可以容纳 HN = NH。在还原和质子化之后,HN=NH通过由 N 2 H 3 –和 NH 2 –桥接的关键中间复合物转化为 NH 3物种。值得注意的是,最终的氨释放受水作为质子源的影响。进行了密度泛函理论计算,提出了生物固氮途径。