ESIPT inspired dual fluorescent probe (Z)-3-((4-(4-aminobenzyl) phenyl) amino)-1,3-diphenylprop-2-en-1-one: experimental and DFT based approach to photophysical properties.

A fluorescent probe (Z)-3-((4-(4-aminobenzyl) phenyl) amino)-1,3-diphenylprop-2-en-1-one (L) was synthesized and characterized by IR, (1)H NMR, ESI mass, UV-visible and fluorescence spectroscopy and by single crystal X-ray diffraction. The molecule has a stable helical structure due to intermolecular CH π interaction. The thermal stability of L was studied by TG analysis. The electronic structure calculations of L have been carried out using DFT at B3LYP/6-31G (d,p) level. The vibrational frequencies and (1)H NMR spectra were computed at this level and compared with experimental values. Major orbital contributions for the electronic transitions were assigned with the help of time-dependent density functional theory (TD-DFT). The observed electronic absorption spectra of L in different solvents coincide with the computed spectra in keto form. The dual emission and high Stokes shift values support the excited state intramolecular proton transfer (ESIPT) process. The molecular docking has been employed to get information about the interaction of L with DNA [6BNA].