Herein, we have studied the analysis of fluorescence quenching for newly synthesized biologically active 3(2H)-pyridazinone derivative 5-(5-bromo-2-hydroxy-phenyl)-2-phenyl-2H-pyridazin-3-one [BHP] by various concentrations of aniline using UV-Visible spectroscopy, fluorescence spectroscopy and time-correlated single photon counting technique in five different solvents namely, methanol, ethanol, propan-2-ol, dimethylsulfoxide and ethyl acetate at room temperature. The fluorescence intensity of BHP molecule decrease with increasing in the aniline concentration and it is studied using the Stern-Volmer relation. The obtained Stern-Volmer plots were found to be linear in all the five solvents. The various parameters responsible for the fluorescence quenching such as quenching rate parameters (k q ), diffusion rate parameter (k d ) and the probability of quenching per encounter (p) were experimentally calculated in all five solvents. An activation energy of quenching (E a ) was calculated using the values of activation energy of diffusion (E d ) and p. It was found that the values of E a are greater than E d in all five solvents studied. Further, it is inferred that the fluorescence quenching reactions in BHP molecule are more significantly affected by activation energy processes.
Keywords: 3(2H)-pyridazinone; Activation energy; Fluorescence quenching; Material diffusion; Stern-Volmer relation.