A diiron(IV) complex that cleaves strong C-H and O-H bonds.
A diiron(IV) complex that cleaves strong C-H and O-H bonds.
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对化学家来说，控制强碳氢键（如甲烷的碳氢键）的裂解是一个重大挑战。在自然界中，甲烷被可溶性甲烷单加氧酶通过二铁（IV）中间体q氧化为甲醇。为了模拟MMO-Q的化学反应，我们通过电化学氧化生成了一个氧桥式二铁（IV）配合物，并用几种光谱方法对其进行了表征。这种新物质对二茂铁的FeIV/III氧化还原电位为+1.50 V（对NHE的FeIV/III氧化还原电位为bbb20 V），这是迄今为止铁配合物电化学测定的最高值。这种植物是一种相当有效的氧化剂。它可以攻击强度高达100 kcal mol - 1的碳氢键，与环己烷反应的速度比密切相关配体的单核FeIV=O配合物快100到1000倍。引人注目的是，该物种还可以切割甲醇和叔丁醇的强O-H键，而不是它们较弱的C-H键，这是铁配合物O-H键激活的第一个例子。
The controlled cleavage of strong C-H bonds like those of methane poses a significant challenge for chemists. In nature methane is oxidized to methanol by soluble methane monooxygenase via a diiron(IV) intermediate called Q. To model the chemistry of MMO-Q, an oxo-bridged diiron(IV) complex has been generated by electrochemical oxidation and characterized by several spectroscopic methods. This novel species has an FeIV/III redox potential of +1.50 V vs. ferrocene (>2 V vs. NHE), the highest value thus far determined electrochemically for an iron complex. This species is quite an effective oxidant. It can attack C-H bonds as strong as 100 kcal mol−1 and reacts with cyclohexane a hundred- to a thousand-fold faster than mononuclear FeIV=O complexes of closely related ligands. Strikingly, this species can also cleave the strong O-H bonds of methanol and tert-butanol instead of their weaker C-H bonds, representing the first example of O-H bond activation for iron complexes.