Electron Transfer Reaction in the Triplet State. Role of Ferrocene as an Electron Donor

Abstract
Quenching of the triplet state of methylene blue by ferrocene and p-phenylenediamine in ethanol has been investigated by an emission-absorption flash technique. The triplet dye is quenched by ferrocene and p-phenylenediamine at a diffusion-controlled rate, yielding the semi-reduced dye. Efficiency of the semi-reduced dye formation is 0.09 and 1.0 for ferrocene and p-phenylenediamine, respectively. Since the triplet level of the dye is lower than that of ferrocene, quenching of the triplet dye by ferrocene seems to occur through the charge (electron) transfer interaction.