Kinetic and redox characteristics of semireduced species derived from phenosafranine in homogeneous aqueous and sodium dodecyl sulfate micellar media

Abstract

One-electron reduction of phenosafranine (PS⁺ 3,7-diamino-5-phenylphenazinium chloride), a phenazinium dye, has been studied in homogeneous aqueous and sodium dodecyl sulfate (SDS) micellar media, using the pulse radiolysis technique. The various reducing radicals employed for the study in homogeneous aqueous medium were e_aq^-, H^•, CO₂^•-, and isopropyl ketyl radicals (CH₃)₂^•COH. Semireduced species generated by these reactions have been characterized by their absorption spectra, decay kinetics, and pK_a. The one-electron reduction potential of PS⁺ was determined at pH 7 in homogeneous aqueous solution employing nitrobenzene (NB/NB^•-) as the standard couple. One-electron reduction in SDS micellar medium and a detailed spectrophotometric investigation of the parent dye in this surfactant system was carried out in order to understand the dye-surfactant interactions in the micellar and premicellar media.