Photoelectrochemical study of the radical anion cleavage rates in aromatic molecules: Halobenzoic acids

The cleavage rates of transient aromatic radical anions of halobenzoic acids ( k c =10 3 –10 9 s −1 ) have been measured in water using a photoelectrochemical method based on photoelectron injection from a metal into an electrolyte solution. Values of k c have been determined from the dependence of the photoinduced cathode charge on the concentration of substances studied. Results indicate that k c depends on the nature of the halogen and its position in the ring relative to the carboxylate group, increasing in the series F