Reactive pendant Mn=O in a synthetic structural model of a proposed S4 state in the photosynthetic oxygen evolving complex
Reactive pendant Mn=O in a synthetic structural model of a proposed S4 state in the photosynthetic oxygen evolving complex
复制标题
光合放氧复合物中拟议的 S4 态的合成结构模型中的反应性侧链 Mn=O
DOI：
10.1021/scimeetings.0c02541
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Shivaiah Vaddypally, Michael J.
中科院分区：
文献类型：
--
作者：
Shivaiah Vaddypally, Michael J.
光系统II的放氧中心的分子机制已经争论了几十年。一个经常被引用的建议是水的氢氧化物的亲核攻击上的一个悬挂的锰氧化物部分，虽然没有化学例子，这种反应性在锰立方烷簇已被报道。我们在这里描述的制备，表征和反应性研究的合成锰立方烷簇与悬垂锰氧代部分。该簇与烯烃的反应导致氧和氢原子转移反应以形成基于醇和酮的含氧产物。从核心酰亚胺转移的氮烯可以忽略不计。无机产物是一个簇相同的前体，但与悬垂Mn的MnO2 O部分取代的氢提取的有机基板，并在定量产量分离。18O和2H同位素标记的研究证实了原子之间的转移簇和有机基板。结果表明，该模型化合物的核心立方烷结构保持完整，并且侧基Mn：O部分优先反应。
The molecular mechanism of the Oxygen Evolving Center of photosystem II has been under debate for decades. One frequently cited proposal is the nucleophilic attack by water hydroxide on a pendant MnO moiety, though no chemical example of this reactivity at a manganese cubane cluster has been reported. We describe here the preparation, characterization, and a reactivity study of a synthetic manganese cubane cluster with a pendant manganese-oxo moiety. Reaction of this cluster with alkenes results in oxygen and hydrogen atom transfer reactions to form alcohol- and ketone-based oxygen-containing products. Nitrene transfer from core imides is negligible. The inorganic product is a cluster identical to the precursor, but with the pendant MnO moiety replaced by a hydrogen abstracted from the organic substrate, and is isolated in quantitative yield.18O and2H isotopic labeling studies confirm the transfer of atoms between the cluster and the organic substrate. The results suggest that the core cubane structure of this model compound remains intact, and that the pendant MnO moiety is preferentially reactive.