Light-driven activation of carbon-halogen bonds by readily available amines for photocatalytic hydrodehalogenation

A straightforward protocol using readily available aromatic amines, N,N,N',N'-tetramethylp-phenylenediamine or N,N,N',N'-tetramethylbenzidine, as photocatalysts was developed for the efficient hydrodehalogenation of organic halides, such as 4'-bromoacetophenone, polyfluoroarenes, cholorobenzene, and 2,2',4,4'-tetrabromodiphenyl ether(a resistant and persistent organic pollutant). The strongly reducing singlet excited states of the amines enabled diffusion-controlled dissociative electron transfer to effectively cleave carbon-halogen bonds, followed by radical hydrogenation. Diisopropylethylamine served as the terminal electron/proton donor and regenerated the amine sensitizers. (c) 2020, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.