Organized media effect on the photochemical deoxygenation of resazurin in the presence of triethanolamine

Abstract

The photodeoxygenation of the synthetic dye resazurin in the presence of triethanolamine was investigated in water, CTAC and SDS direct micelles, AOT and BHDC reverse micelles, and soybean lecithin microemulsions (LEC). In all cases the only product observed was the deoxygenated dye resorufin. Triplet and reaction quantum yields were determined in all media. The photoreaction proceeds more efficiently in the microheterogenous systems with positive interface, CTAC and BHDC, while the lower yield is observed in AOT, SDS and LEC. The initial step in the mechanism is the interaction of the triplet state of the dye with the amine, and the effect of the interface is interpreted by a decrease of the recombination rate of the radicals formed in the initial electron transfer step. Negative and zwitterionic interfaces have no effect on the quantum yield.