Ammonia formation by a thiolate-bridged diiron amide complex as a nitrogenase mimic
Ammonia formation by a thiolate-bridged diiron amide complex as a nitrogenase mimic
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硫醇桥联二铁酰胺复合物作为固氮酶模拟物形成氨
DOI：
10.1038/nchem.1594
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发表时间：
2013-04-01
期刊：
影响因子：
21.8
通讯作者：
Qu, Jingping
中科院分区：
文献类型：
--
作者：
Li, Yang;Li, Ying;Qu, Jingping
虽然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方法进行，该方法需要极端的温度和压力来活化双氮。生物固定发生通过双氮和还原NxHy物种在多铁中心的含硫配体的化合物，但它是很难阐明的机制细节，并获得稳定的模型中间体配合物进行进一步研究。基于金属的合成模型已被应用于揭示部分细节，尽管大多数模型涉及单核系统。在这里，我们报告了一个二铁配合物桥接的双齿硫醇配体，可以容纳HN=NH。在还原和质子化之后，HN=NH通过由N2 H3-和NH 2-物种桥接的关键中间体络合物转化为NH3。值得注意的是，最终的氨释放是用水作为质子源实现的。通过密度泛函理论计算，提出了生物固氮的途径。
Although nitrogenase enzymes routinely convert molecular nitrogen into ammonia under ambient temperature and pressure, this reaction is currently carried out industrially using the Haber-Bosch process, which requires extreme temperatures and pressures to activate dinitrogen. 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 to reveal partial details, although most models involve a mononuclear system. Here, we report a diiron complex bridged by a bidentate thiolate ligand that can accommodate HN=NH. Following reductions and protonations, HN=NH is converted to NH3 through pivotal intermediate complexes bridged by N2H3- and NH2- species. Notably, the final ammonia release was effected with water as the proton source. Density functional theory calculations were carried out, and a pathway of biological nitrogen fixation is proposed.