Triplet state interaction of Safranine T with inorganic cations in different solvents

The triplet-triplet absorbance of Safranine T (3,7-Diamino-2,8-dimethyl-5-phenylphenaznium chloride) has been studied in a series of polar and non-polar solvents. When non-aqueous solvents are gradually added to the aqueous solution of Safranine T (ST) the lifetime of the triplet state decreases. It has been established that the dye forms weak complex with the solvent molecules. The quenching of triplet state of ST by Fe2+, Co2+ and Mn2+ has been studied in different solvents. The double protonated long-lived triplet species of ST; DH2+23 absorbs at 580 nm. The decay of the triplets follows first order kinetics. The quencher generates reduced semidye from 3ST by electron transfer mechanism. The reduction of 3ST by Mn2+ and Fe2+ is thermodynamically allowed but electron transfer from Co2+ to ST is endoergic. The mechanism of quenching by Co2+ can be explained as compensation by charge transfer mechanism between 3ST and Co2+.