The mechanism of the electrode oxidation of 5,10-dimethyl-5,10-dihydrophenazine in cationic micellar solution

Abstract

The electrode oxidation mechanism of a neutral substance, 5,10-dimethyl-5,10-dihydrophenazine (DMPZ), in cationic micellar solutions of alkyltrimethylammonium bromide was studied. Cyclic voltammetry and the spectrophotometric determination of the solubility of DMPZ in micellar solution led to the conclusion that the micelle solubilization equilibrium of DMPZ obeyed the Poisson distribution. A formal oxidation potential which water-insoluble DMPZ would have in water, (−0.041±0.010) V vs. SCE, was determined on this basis. The result of potential-step chronoamperometry could be interpreted on the basis of the proposed reaction scheme, in which the charge-transfer process was preceded by the exit process of DMPZ from the micelle into the water. The exit rate constants ranged from 10 3 to 10 4 s −1, depending on the surfactants' alkyl chain lengths which ranged from C 16 to C 12.