Homogenous redox catalysis competition between electron exchange and proton exchange

Whether proton exchange and nucleophilic substitution reactions can become competitive with electron exchange reactions in homogeneous redox catalysis processes due to the reduction of bromoesters has been evaluated.Electrochemical data have been correlated with the results of the analyses carried out in solution during, and at the end of, the catalytic reduction processes. Thus, it has been possible to obtain the values of γ (γ = c_RX/c_O, where c_RX is the substrate concentration and c_O that of the catalyst corresponding to pure catalysis conditions whereby only the electron-exchange reaction is observed.The hypothesis that the catalyst (9,10-diphenylanthracene) is dihydrogenated by the substrate according to DISP₂ mechanism is in agreement with the experiments.