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Updated: Mar 22, 2026

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes
Published on: April 10, 2015
Four-Electron Oxidation of Phenols to p-Benzoquinone Imines by a (Salen)ruthenium(VI) Nitrido Complex
Jianhui Xie1, Wai-Lun Man1, Chun-Yuen Wong1
1Department of Biology and Chemistry and Institute of Molecular Functional Materials, City University of Hong Kong , Tat Chee Avenue, Hong Kong, China.
Abstract:
Proton-coupled electron-transfer reactions of phenols have received considerable attention because of their fundamental interest and their relevance to many biological processes. Here we describe a remarkable four-electron oxidation of phenols by a (salen)ruthenium(VI) complex in the presence of pyridine in CH3OH to afford (salen)ruthenium(II) p-benzoquinone imine complexes. Mechanistic studies indicate that this reaction occurs in two phases. The first phase is proposed to be a two-electron transfer process that involves electrophilic attack by Ru≡N at the phenol aromatic ring, followed by proton shift to generate a Ru(IV) p-hydroxyanilido intermediate. In the second phase the intermediate undergoes intramolecular two-electron transfer, followed by rapid deprotonation to give the Ru(II) p-benzoquinone imine product.
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