Visible Light-Induced Oxidation of Alcohols by a Luminescent Osmium(VI) Nitrido Complex: Evidence for the Generation of PhIO+ as a Highly Active Oxidant in the Presence of PhIO

13 Apr 2023

Published on Journal of The American Chemical Society (13 April 2023)

Author(s): Jing Xiang*, Yi Pan, Lu-Lu Liu, Li-Xin Wang, Huan Yang, Shun-Cheung Cheng , Shek-Man Yiu, Chi-Fai Leung, Chi-Chiu Ko*, Kai-Chung Lau*, and Tai-Chu Lau*

Abstract

Although alcohols are readily oxidized by a variety of oxidants, their oxidation by metal nitrido complexes is yet to be studied. We report herein visible-light-induced oxidation of primary and secondary alcohols to carbonyl compounds by a strongly luminescent osmium(VI) nitrido complex (OsN). The proposed mechanism involves initial rate-limiting hydrogen-atom transfer (HAT) from the α-carbon of the alcohol to OsN*. Attempts to develop catalytic oxidation of alcohols by OsN* using PhIO as the terminal oxidant resulted in the formation of novel osmium(IV) iminato complexes in which the nitrido ligand is bonded to a δ-carbon of the alcohol. Experimental and theoretical studies suggest that OsN* is reductively quenched by PhIO to generate PhIO+, which is a highly active oxidant that readily undergoes α- and δ-C–H activation of alcohols.

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