CHARGE-TRANSFER COMPLEXES BETWEEN INDOLE-DERIVATIVES AND METHYL VIOLOGEN IN NORMAL AND REVERSE MICELLAR SYSTEMS

The charge transfer interaction between methyl viologen (MV+2) and try ptophan (Trp), indole acetic acid (IAA) and indole butyric acid (IBA) was studied in water, in aqueous solutions of sodium dodecyl sulfate ( SDS), cetyltrimethylammonium chloride (CTAC) and in reverse micelles o f sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in heptane. The apparen t association constants were determined. In the presence of SDS or CTA C the values are of the same order of magnitude as in water, but they depend upon the surfactant concentration. In AOT the values of the equ ilibrium constant for IAA and Trp are very much higher than in water a nd they show a strong dependence upon the water/surfactant ratio (R). For IBA the values are much lower, similar to those in water and show practically no variation with R. These effects may be explained by con sidering the partitioning of the components between the different micr ophases. Laser flash photolysis of the complex produces the radical ca tion of methyl viologen in low yield only in the case of CTAC solution s where the process of charge separation is favoured.