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 Fe2C, Co2C and Mn2C has been studied in different solvents. The double protonated long-lived triplet species of ST; 3DH22 C 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 Mn2C and Fe2C is thermodynamically allowed but electron transfer from Co2C to ST is endoergic. The mechanism of quenching by Co2C can be explained as compensation by charge transfer mechanism between 3ST and Co2C. q 2005 Elsevier B.V. All rights reserved.