Analysis of fluorescence quenching of new indole derivative by aniline using Stern-Volmer plots

The fluorescence quenching of 5-methyl-3-phenyl-2-[4'-amino-s-triazolo-3'-yl] indole-5'-hydrazide (MPIH) by aniline quencher in cyclohexane, benzene, toluene and dioxane solvents has been carried out at room temperature with a view to understand the quenching mechanisms. The quenching is found to be appreciable and shows positive deviation in the Stern-Volmer plots. The various quenching parameters have been determined using modified Stern-Volmer equation, which suggests that the sphere of action static quenching model agrees very well with the experimental results and this positive deviation is attributed to the static and dynamic quenching. Further, with the use of the finite sink approximation model, it is concluded that these bimolecular quenching reactions are diffusion limited and the distance parameter R' and mutual diffusion co-efficient D are estimated independently. (c) 2005 Elsevier B.V. All rights reserved.