Fluorescence quenching of coumarin derivative by amino anilines

The effect of stereo electronic factors of ortho-phenylenediamine OPD and para-phenylenediamine during PPD their interaction with 5, 6 benzo-4-azidomethyl coumarin 5BAMC in a binary solvent mixture of THF and water has been studied. From fluorescence quenching study, interaction between and is due to collisional quenching and between 5BAMC and is due to both static and dynamic quenching, Quenching efficiency of PPD is more than OPD. Based on the magnitudes of change in enthalpy, change in entropy and free energy changer interaction between 5BAMC-PPD is hydrophobic and spontaneous. There is a Forster resonance energy transfer from 5BAMC to PPD. (author)