A combined experimental and DFT-TDDFT study of the excited-state intramolecular proton transfer (ESIPT) of 2-(2'-hydroxyphenyl) imidazole derivatives.

We report a combined experimental and computational study of the effect of electron donor and acceptor groups on the excited state intramolecular proton transfer of 2-(2'-hydroxyphenyl) imidazole derivatives in solvents of different polarities. The changes in fluorescence properties, electronic transitions and energy levels are analyzed and discussed. The study was complemented using the Density Functional Theory (DFT)-Time Dependent DFT [B3LYP/6-31G(d)] computations. The calculated absorption and emission spectra of the imidazole derivatives are in good agreement with the experiments, thus allowing an assignment of the UV-vis spectra.