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 Fe 2+ , Co 2+ and Mn 2+ has been studied in different solvents. The double protonated long-lived triplet species of ST; DH 2 + 2 3 absorbs at 580 nm. The decay of the triplets follows first order kinetics. The quencher generates reduced semidye from 3 ST by electron transfer mechanism. The reduction of 3 ST by Mn 2+ and Fe 2+ is thermodynamically allowed but electron transfer from Co 2+ to ST is endoergic. The mechanism of quenching by Co 2+ can be explained as compensation by charge transfer mechanism between 3 ST and Co 2+ .