Synthetic models for the active site of the [FeFe]-hydrogenase: catalytic proton reduction and the structure of the doubly protonated intermediate.
Synthetic models for the active site of the [FeFe]-hydrogenase: catalytic proton reduction and the structure of the doubly protonated intermediate.
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DOI：
10.1021/ja309216v
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发表时间：
2012-11-14
影响因子：
15
通讯作者：
Carroll, Patrick J.
中科院分区：
文献类型：
--
作者：
Carroll, Maria E.;Barton, Bryan E.;Rauchfuss, Thomas B.;Carroll, Patrick J.
本报告比较了含有和不含胺辅因子 (adtNH) 的仿生 HER 催化剂：Fe2(adtNH)(CO)2(dppv)2 (1NH) 和 Fe2(pdt)(CO)2(dppv)2 (2; (adtNH)2− = (HN(CH2S)22−, pdt2− = 1,3-(CH2)3S22−)。这些化合物是1NH 和 2 的质子化在光谱、结构和立体动力学上非常相似，但表现出非常不同的催化性质，从动力学上有利的末端氢化物开始，依次转化为桥接氢化物的对称和非对称异构体。铵/胺氢化物平衡对抗衡阴离子和溶剂敏感。[t-H1NH2](BF4)2 代表了通过质子化产生的晶体学特征的末端氢化物的第一个例子。NH--HFe 距离为 1.88(7) Å，表明桥接氢化物 [μ-H1NH]+ 和 [μ-H2]+ 在接近 -1.8 V 时还原，大约高出 150 mV。比末端氢化物 [t-H1NH]+ 和 [t-H2]+ 在 -1.65 V 时的还原为负。胺氢化物 [t-H1NH]+ 和 [t-H1NH2]2+ 的还原是不可逆的。对于 pdt 类似物，[t-H2]+/0 对不受弱酸 (pKaMeCN 15.3) 的影响，但表现出催化作用。 HBF4·Et2O，尽管 TOF 约为 4 s−1 且过电位大于 1 V。[t-H1NH]+ 的伏安法受相对弱酸的强烈影响，并在 5000 s−1 下进行，过电位为 0.7 V。氢化铵 [t-H1NH2]2+ 是一种更快的催化剂，估计 TOF 为 58,000 s−1，并且0.5V的过电位。
This report compares biomimetic HER catalysts with and without the amine cofactor (adtNH): Fe2(adtNH)(CO)2(dppv)2 (1NH) and Fe2(pdt)(CO)2(dppv)2 (2; (adtNH)2− = (HN(CH2S)22−, pdt2− = 1,3-(CH2)3S22−). These compounds are spectroscopically, structurally, and stereodynamically very similar but exhibit very different catalytic properties. Protonation of 1NH and 2 each give three isomeric hydrides beginning with the kinetically favored terminal hydride, which converts sequentially to sym and unsym isomers of the bridging hydrides. In the case of the amine, the corresponding ammonium-hydrides are also observed. In the case of the terminal amine hydride [t-H1NH]BF4, the ammonium/amine-hydride equilibrium is sensitive to counteranions and solvent. The species [t-H1NH2](BF4)2 represents the first example of a crystallographically characterized terminal hydride produced by protonation. The NH--HFe distance of 1.88(7) Å indicates dihydrogen bonding. The bridging hydrides [µ-H1NH]+ and [µ-H2]+ reduce near −1.8 V, about 150 mV more negative than the reductions of the terminal hydride [t-H1NH]+ and [t-H2]+ at −1.65 V. Reductions of the amine hydrides [t-H1NH]+ and [t-H1NH2]2+ are irreversible. For the pdt analog, the [t-H2]+/0 couple is unaffected by weak acids (pKaMeCN 15.3) but exhibits catalysis with HBF4•Et2O, albeit with a TOF around 4 s−1 and an overpotential greater than 1 V. The voltammetry of [t-H1NH]+ is strongly affected by relatively weak acids and proceeds at 5000 s−1 with an overpotential of 0.7 V. The ammonium-hydride [t-H1NH2]2+ is a faster catalyst with an estimated TOF of 58,000 s−1 and an overpotential of 0.5 V.
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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：
Cheah, Mun Hon;Tard, Cedric;Best, Stephen P.
通讯作者：
Best, Stephen P.
[FEFE] - 氢化酶的活性位点的混合价模型的氧化还原和结构特性：进步和挑战。
影响因子：
4.6
作者：
Justice AK;De Gioia L;Nilges MJ;Rauchfuss TB;Wilson SR;Zampella G
通讯作者：
Zampella G
影响因子：
4.6
作者：
Fourmond, Vincent;Jacques, Pierre-Andre;Artero, Vincent
通讯作者：
Artero, Vincent
影响因子：
16.6
作者：
Bruschi, Maurizio;Greco, Claudio;De Gioia, Luca
通讯作者：
De Gioia, Luca