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Noble-metal-based bimetallic oxide clusters are promising novel catalysts. In this study, we developed carbon-supported RhRu bimetallic oxide clusters (RhRuOx/C) with a mean diameter of 1.2 nm, which showed remarkable catalytic activity for the cross-dehydrogenative coupling (CDC) of arenes and carboxylic acids with O2 as the sole oxi-dant. RhRu bimetallic oxide cluster formation was confirmed by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy and synchrotron X-ray absorp-tion spectroscopy. Kinetic isotope and substituent effects indicated that arene C–H bond cleavage was the rate-determining step and proceeded via electrophilic concerted metalation–deprotonation mechanism, with a carbox-ylate as an internal base. Density functional theory calculations supported the proposed mechanism and indicated that the active center for C–H bond activation was Rh(V) rather than Rh(III), while Ru enhanced the electrophilicity of the Rh(V) site by decreasing the negative charge of the surrounding oxygen atoms. Electron-rich arenes showed rela-tively high reactivity for RhRuOx/C-catalyzed CDC reaction, and both aliphatic and aromatic carboxylic acids were applicable to the reaction. The RhRuOx/C catalyst is promising for the CDC reaction of arenes and carboxylic acids to produce aryl esters. This work will promote the development of noble-metal-based bimetallic oxide clusters for C–H bond activation reactions.

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• In Copyright
  This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society, copyright © 2024 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/jacs.4c03467

Keyword: catalyst, bimetallic nanoparticles, scanning transmission electron microscopy, cross-dehydrogenative coupling

Date published: 2024-07-17

Publisher: American Chemical Society (ACS)

Journal:

• Journal of the American Chemical Society (ISSN: 15205126) vol. 146 issue. 28 p. 19059-19069

Funding:

• Japan Society for the Promotion of Science JP22K20554
• Japan Society for the Promotion of Science JP23H04874
• Japan Society for the Promotion of Science JP23K13602
• Japan Society for the Promotion of Science JP23K23131
• Tokyo Ohka Foundation for The Promotion of Science and Technology

Manuscript type: Author's version (Accepted manuscript)

MDR DOI:

First published URL: https://doi.org/10.1021/jacs.4c03467

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Updated at: 2024-08-26 16:31:01 +0900

Published on MDR: 2025-06-06 08:20:15 +0900