CATION RADICALS OF PHENOTHIAZINES - ELECTRON-TRANSFER WITH AQUOIRON(II) AND AQUOIRON(III) AND HEXACYANOFERRATE(II) AND HEXACYANOFERRATE(III)

The rates of electron transfer of three different groups of reactions involving N-alkylphenothiazines (PTZ) have been obtained in aqueous perchloric acid medium by means of stopped-flow and T-jump spectrophotometric techniques: (1) the electron transfer between the cation radical and different PTZ derivatives; (2) the oxidation of PTZ by Fe(H2O)63+; (3) the oxidation of PTZ by Fe(CN)63-. Electron transfers involving Fe(CN)63- are in agreement with the Marcus theory, while oxidation by Fe(III) shows an expected dependence of activation free energy on overall free energy change, although the calculated values are 300-500 times higher than the experimental ones. © 1979, American Chemical Society. All rights reserved.