Use of Organic Molecules as Mechanistic Probes for Semiconductor-Mediated Photoelectrochemical Oxidations: Bromide Oxidation

Article abstract of DOI:10.1021/jo00225a001

Cyclohexene has been used as an organic probe for mechanism in the semiconductor-photocatalyzed oxidation of bromide in acetonitrile.Products derived from bromine addition and from cyclohexenyl radical mediated autoxidation were isolated.These results implicate a mechanism in which the photoexcited semiconductor effects a one electron oxidation of adsorbed bromide, producing surface-bound bromine atoms.These potentially could abstract hydrogen from cyclohexene to initiate autoxidation or could migrate along the semiconductor surface, producing bromine (Br2), which migrates into solution where it is rapidly trapped in conventional electrophilic addition.