TIME-RESOLVED EPR STUDIES OF PHOTO-INITIATED ELECTRON-TRANSFER AND SPIN DYNAMICS OF PORPHYRIN QUINONE MIXTURES IN MICELLAR SYSTEMS

We report on time-resolved EPR experiments of the photo-induced electr on transfer from zinc-tetraphenylporphyrin (ZnTPP) to duroquinone (DQ) in cationic CTAC and neutral Triton X-100 micelles. The spin-polarize d EPR spectra and their time-dependence indicate pronounced difference s between the two micellar systems: In the neutral micelles, the lifet ime of the spin-correlated radical pair is longer than in the charged micelles. In the CTAC system an unusual temperature dependence of the polarization pattern is observed. This can be attributed to the effect s of both the microviscosity of the micellar interior and the macrovis cosity of the bulk solution on the spin dynamics of the reactants loca ted inside the micelles.