ELECTRON-TRANSFER IN REVERSE MICELLAR SOLUTIONS - INFLUENCE OF THE INTERFACIAL BOUND WATER

The thermal decay of the cation radical of tetramethylbenzidine (TMB) with aqueous nucleophiles was examined in positive (benzyldimethylhexa decylammonium chloride, BHDC) and negative (sodium bis(2-ethylhexyl) s ulfosuccinate, AOT) reverse micelles. It was shown that the rate const ants are slightly affected by the sign of the interfacial charges, con trary to the situation that prevails in direct micelles. A correlation between the dependence of the decay rate constant and the density of the surfactant molecules on the water pool size has been established i n the range 5 less than or equal to omega degrees less than or equal t o 25 for all the micellar solutions. This result points out the decisi ve role of the bound water of the interfacial region, when the electro n transfer occurs from the aqueous to the lipidic phase.