ELECTRON-TRANSFER FROM NUCLEOPHILIC SPECIES TO N,N,N',N'-TETRAMETHYLBENZIDINE CATION IN MICELLAR MEDIA - EFFECT OF INTERFACIAL ELECTRICAL POTENTIAL ON CATION DECAY

Electron-transfer reaction between N,N,N′,N′-tetramethylbenzidine cation (TMB+) and neutral nucleophiles, pyridine (Py) and triethylamine (Et3N), is studied in NaLS micellar media. A biphasic decay of TMB+ follows the laser-induced TMB photoionization. The very fast decay is attributed to an electron transfer between reactants located in the core of the micelle. The slow decay would correspond to an electron transfer from the nucleophile solubilized in the aqueous phase to TMB+ embedded in the lipidic phase. The role of the electrical interfacial potential Δψ is evidenced. The rate constant of the TMB+ slow decay displays an exponential function of Δψ. The effect of the localization and distance of the reactants is emphasized. © 1990 American Chemical Society.