Role of the azadithiolate cofactor in models for [FeFe]-hydrogenase: novel structures and catalytic implications.
Role of the azadithiolate cofactor in models for [FeFe]-hydrogenase: novel structures and catalytic implications.
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DOI：
10.1021/ja103998v
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发表时间：
2010-12-22
影响因子：
15
通讯作者：
Wilson, Scott R.
中科院分区：
文献类型：
--
作者：
Olsen, Matthew T.;Rauchfuss, Thomas B.;Wilson, Scott R.
该报告总结了[FeFe]-氢化酶的合成模型的氧化还原行为的研究，包括二铁二硫羟羰基配合物轴承胺辅因子及其N-苄基衍生物。特别感兴趣的是氧化模型对H2的低反应性的原因，这与这些酶对H2氧化的高活性形成对比。研究了模型配合物[Fe_2 [（SCH_2）_2NR]（CO）_3（dppv）（PMe_3）]~+的氧化还原和酸碱性质（[2]+对于R = H和[2′]+对于R = CH 2C 6 H5，dppv =顺式-1，2-双（二苯基膦基）乙烯））表明，加入H2和随后的去质子化是（i）吸热的混合价态（FeIIFeI）和（ii）放热的二亚铁（FeIIFeII）州。的二价铁状态被证明是不稳定的，相对于协调的胺铁，其衍生物的特征在于晶体。氧化还原和酸碱性质的混合价模型不同强烈的胺辅因子与那些来自propanedithiolate。[2′]+的质子化导致铵-FeIFeI和阳离子[2′]2+（FeIIFeII）的1：1混合物的质子化。这种效果与FeIFeI状态与FeIIFeI状态下胺的碱性的实质性增强一致。FeIFeI铵化合物是氮氧化合物克里思的快速有效的H原子供体。提出了通过氢化物进行原子转移，如[HFe 2 [（SCH 2）2NH]（CO）2（dppv）2]+与克里思的反应所示。总的来说，结果表明，质子耦合的电子转移途径应考虑H2活化的[FeFe]-氢化酶。
The report summarizes studies on the redox behavior of synthetic models for the [FeFe]-hydrogenases, consisting of diiron dithiolato carbonyl complexes bearing the amine cofactor and its N-benzyl derivative. Of specific interest are the causes of the low reactivity of oxidized models toward H2, which contrasts with the high activity of these enzymes for H2 oxidation. The redox and acid-base properties of the model complexes [Fe2[(SCH2)2NR](CO)3(dppv)(PMe3)]+ ([2]+ for R = H and [2′]+ for R = CH2C6H5, dppv = cis-1,2-bis(diphenylphosphino)ethylene)) indicate that addition of H2 and followed by deprotonation are (i) endothermic for the mixed valence (FeIIFeI) state and (ii) exothermic for the diferrous (FeIIFeII) state. The diferrous state is shown to be unstable with respect to coordination of the amine to Fe, a derivative of which was characterized crystallographically. The redox and acid-base properties for the mixed valence models differ strongly for those containing the amine cofactor versus those derived from propanedithiolate. Protonation of [2′]+ induces disproportionation to a 1:1 mixture of the ammonium-FeIFeI and the dication [2′]2+ (FeIIFeII). This effect is consistent with substantial enhancement of the basicity of the amine in the FeIFeI state vs the FeIIFeI state. The FeIFeI ammonium compounds are rapid and efficient H-atom donors toward the nitroxyl compound TEMPO. The atom transfer is proposed to proceed via the hydride, as indicated by the reaction of [HFe2[(SCH2)2NH](CO)2(dppv)2]+ with TEMPO. Collectively, the results suggest that proton-coupled electron-transfer pathways should be considered for H2 activation by the [FeFe]-hydrogenases.
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DOI：
10.1039/b910147k
发表时间：
2010-03-28
期刊：
Dalton transactions (Cambridge, England : 2003)
影响因子：
--
作者：
Barton BE;Zampella G;Justice AK;De Gioia L;Rauchfuss TB;Wilson SR
通讯作者：
Wilson SR
影响因子：
15
作者：
Boyke, CA;Rauchfuss, TB;Bénard, M
通讯作者：
Bénard, M
影响因子：
15
作者：
Cheah, Mun Hon;Tard, Cedric;Best, Stephen P.
通讯作者：
Best, Stephen P.
影响因子：
16.6
作者：
Justice, Aaron K.;Rauchfuss, Thomas B.;Wilson, Scott R.
通讯作者：
Wilson, Scott R.
影响因子：
4.9
作者：
Dong, WB;Wang, M;Sun, LC
通讯作者：
Sun, LC