Activation of a water molecule using a mononuclear Mn complex: from Mn-aquo, to Mn-hydroxo, to Mn-oxyl via charge compensation.
Activation of a water molecule using a mononuclear Mn complex: from Mn-aquo, to Mn-hydroxo, to Mn-oxyl via charge compensation.
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DOI：
10.1039/b926990h
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发表时间：
2010-07-01
影响因子：
32.5
通讯作者：
Anxolabéhère-Mallart E
中科院分区：
文献类型：
--
作者：
Lassalle-Kaiser B;Hureau C;Pantazis DA;Pushkar Y;Guillot R;Yachandra VK;Yano J;Neese F;Anxolabéhère-Mallart E
报道了锰-水络合物的电化学氧化伴随着质子的损失而活化水分子。本文报道了非卟啉型六配位Mn（II）OH_2配合物的顺序（2 × 1电子/1质子）和直接（2电子/2质子）质子偶联电化学氧化为单核Mn（O）配合物。电化学制备和分析中间体Mn（III）OH 2和Mn（III）OH络合物。通过电化学数据证实了Mn（O）络合物中配位水分子的完全去质子化，而EXAFS数据的分析揭示了在从Mn（II）OH 2氧化为Mn（III）OH和Mn（O）时Mn-O键的逐渐缩短。反应性实验，DFT计算和XANES前边缘功能提供了强有力的证据表明，在Mn（O）的键合是最好的特点是由Mn（III）-oxyl描述。这种氧自由基物种在天然和人工水裂解反应中起着至关重要的作用。我们在这里提供了一个合成的例子，这样的物种，通过电化学活化的水配体。
Activation of a water molecule by the electrochemical oxidation of a Mn-aquo complex accompanied by the loss of protons is reported. The sequential (2 × 1 electron/1 proton) and direct (2 electron/2 proton) proton-coupled electrochemical oxidation of a non-porphyrinic six-coordinated Mn(II)OH2 complex into a mononuclear Mn(O) complex is described. The intermediate Mn(III)OH2 and Mn(III)OH complexes are electrochemically prepared and analysed. Complete deprotonation of the coordinated water molecule in the Mn(O) complex is confirmed by electrochemical data while the analysis of EXAFS data reveals a gradual shortening of an Mn–O bond upon oxidation from Mn(II)OH2 to Mn(III)OH and Mn(O). Reactivity experiments, DFT calculations and XANES pre-edge features provide strong evidence that the bonding in Mn(O) is best characterized by a Mn(III)-oxyl description. Such oxyl species could play a crucial role in natural and artificial water splitting reactions. We provide here a synthetic example for such species, obtained by electrochemical activation of a water ligand.