文章基本信息

标题：Dioxygen Activation by Internally Aromatic Metallacycle: Crystallographic Structure and Mechanistic Investigations
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作者：Zhihong Deng ; Peng Wu ; Yapeng Cai 等
期刊名称：iScience
印刷版ISSN：2589-0042
出版年度：2020
卷号：23
期号：8
页码：1-38
DOI：10.1016/j.isci.2020.101379
语种：English
出版社：Elsevier
摘要：SummaryMononuclear metal-peroxo species are invoked as the key intermediates in metalloenzymatic or synthetic catalysis. However, either transience or sluggishness reactivity of synthetic analogs of metal-peroxo species impedes our understanding of oxygen activation mechanism. Herein, we designed and characterized a dioxygen-derived mononuclear osmium-peroxo complex, in which the peroxo ligand is stabilized by internally aromatic metallacycle. We demonstrate that the osmium-peroxo species shows catalytic activity toward promoterless alcohol dehydrogenations. Furthermore, computational studies provide a new mechanism for the osmium-peroxo-mediated alcohol oxidation, starting with the concerted double-hydrogen transfer and followed by the generation of osmium-oxo species. Interestingly, the internally aromatic metallacycle also plays a vital role in catalysis, which mediates the hydrogen transfer from osmium center to the distal oxygen atom of Os–OOH moiety, thus facilitating the Os–OOH→Os=O conversion. We expect that these insights will advance the development of aromatic metallacycle toward aerobic oxidation catalysis.Graphical AbstractDisplay OmittedHighlights•A dioxygen-derived mononuclear osmium-peroxo complex was characterized•The peroxo ligand is stabilized by internally aromatic metallacycle•O2activation involves the reversible aromatization-dearomatization•A concerted double-hydrogen transfer mechanism for alcohol dehydrogenationChemistry; Inorganic Chemistry; Organometallic Chemistry; Catalysis