Photoreduction of Chloranil by Benzhydrol and Related Compounds. Hydrogen Atom Abstraction vs Sequential Electron-Proton Transfer via Quinone Triplet Radical Ion-Pairs

摘要

The photoreduction of chloranil (Q) to the hydroquinone (QH_2) in benzhydrols and by related arylmethanols has been investigated. The products of photooxidation of the benzhydrols are benzophenones, in lieu of formation of benzpinacols. Three distinct mechanisms of oxidation-reduction have been identified from quantum yield determinations and laser flash photolysis experiments, including quinone triplet quenching via H-atom and electron transfer paths.