PHOTOREDUCTION OF THIONINE AND SURFACTANT THIONINE BY IRON(II) IN ANIONIC MICELLES AND MICROEMULSIONS.

Article abstract of DOI:10.1002/bbpc.19850890513

The rate constants for the iron(II)-thionine and surfactant thionine system have been determined in aqueous solution, sodium dodecyl sulfate (SDS) micelles, and in a mineral oil-in-water microemulsion stabilized by sodium cetyl sulfate (SCS) and 1-pentanol. The triplet lifetimes are all in the range 7-9 mu s. The rate constant for electron transfer quenching of triplet thionine by iron(II) is higher in the anionic media due to a higher local Fe**2** plus concentration. However, the back reaction between semithionine and iron(III) is not similarly enhanced in the presence of micelles or microemulsion. The dismutation of semithionine is a little slower in microemulsion than in water, but over two orders of magnitude slower in SDS micelles. The quantum yield of thionine triplet formation, determined for surfactant thionine in SCS microemulsion, approaches unity.