A Ruthenium(III)-Oxyl Complex Bearing Strong Radical Character

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• 作者：Yoshihiro Shimoyama ; Dr. Tomoya Ishizuka ; Dr. Hiroaki Kotani ; Prof. Dr. Yoshihito Shiota ; Prof. Dr. Kazunari Yoshizawa ; Dr. Kaoru Mieda ; Prof. Dr. Takashi Ogura ; Dr. Toshihiro Okajima ; Prof. Dr. Shunsuke Nozawa and Prof. Dr. Takahiko Kojima
• 刊名：Angewandte Chemie International Edition
• 出版年：2016
• 出版时间：November 2, 2016
• 年：2016
• 卷：55
• 期：45
• 页码：14041-14045
• 全文大小：966K
• ISSN：1521-3773

文摘

Proton-coupled electron-transfer oxidation of a Ru^II−OH₂ complex, having an N-heterocyclic carbene ligand, gives a Ru^III−O^. species, which has an electronically equivalent structure of the Ru^IV=O species, in an acidic aqueous solution. The Ru^III−O^. complex was characterized by spectroscopic methods and DFT calculations. The oxidation state of the Ru center was shown to be close to +3; the Ru−O bond showed a lower-energy Raman scattering at 732 cm⁻¹ and the Ru−O bond length was estimated to be 1.77(1) Å. The Ru^III−O^. complex exhibits high reactivity in substrate oxidation under catalytic conditions; particularly, benzaldehyde and the derivatives are oxidized to the corresponding benzoic acid through C−H abstraction from the formyl group by the Ru^III−O^. complex bearing a strong radical character as the active species.