Stepwise N-H bond formation from N2-derived iron nitride, imide and amide intermediates to ammonia
Stepwise N-H bond formation from N2-derived iron nitride, imide and amide intermediates to ammonia
复制标题
DOI：
10.1039/c6sc00423g
复制
发表时间：
2016-01-01
期刊：
影响因子：
8.4
通讯作者：
Holland, Patrick L.
中科院分区：
文献类型：
--
作者：
MacLeod, K. Cory;McWilliams, Sean F.;Holland, Patrick L.
在自然界和电催化中，N-2还原成氨是通过1-质子/1-电子步骤进行的，这促使人们努力实验研究质子/电子转移到具有桥接氮化物的良好特征的N-2衍生物种期间的步骤。我们在此报道了N-2衍生的铁双（氮化物）络合物的质子化和还原反应（Rodriguez等人，Science，2011，334，780）。我们隔离和明确的特点三铁亚氨基和酰胺中间体，位于沿着的路径形成氨，穆斯堡尔谱显示在这些混合价簇的铁原子的氧化水平。前两个H原子添加到双（氮化物）络合物的两个氮化物中的一个，并且第二步骤中的质子耦合电子转移可以是协同的或逐步的，这取决于质子和电子的来源。部分质子化氮化物的表征及其形成机制有望指导用弱酸将N-2转化为氨的努力。
Reduction of N-2 to ammonia in nature and in electrocatalysis takes place through 1-proton/1-electron steps, motivating efforts to experimentally study the steps during proton/electron transfer to well-characterized N-2-derived species with bridging nitrides. We report here the protonation and reduction reactions of an N-2-derived iron bis(nitride) complex (Rodriguez et al., Science, 2011, 334, 780). We isolate and definitively characterize triiron imido and amido intermediates that lie along the path to ammonia formation, and Mossbauer spectroscopy shows the oxidation level of iron atoms in these mixed-valence clusters. The first two H atoms add to one of the two nitrides of the bis(nitride) complex, and the proton-coupled electron transfer in the second step can be concerted or stepwise depending on the sources of protons and electrons. The characterization of partially protonated nitrides and their mechanisms of formation are expected to guide efforts to convert N-2 to ammonia with mild acids.