Phototautomerization in 9-hydroxy-5H-indeno[1,2-b]pyridin-5-one a Quantum Chemical Approach

The organic dyes undergoing excited-state intramolecular proton transfer (ESIPT) have receivedconsiderable attention during the past several decades, due to its practical and potential applications inmany fields [12]. In ESIPT systems, a proton (or hydrogen atom) transfer from one the hydrogen donorgroup (usually a phenolic OH group or amino-type) to the acceptor of the proton (usually a heterocyclicnitrogen atom or a carbonyl group) in the electronically excited state of a molecule, through the formationof a five-, six- or seven-membered ring with a strong intramolecular hydrogen bond (H-bond) between theproton donor and acceptor group 3,4. The purpose of the present work is to explore thephototautomerization in 9-hydroxy-5H-indeno[1,2-b]pyridin-5-one (HIPO) (Scheme 1) at PBE1PBE-D/6-311++G(d,p) level of theory. The stationary points on the S0 and S1 potential energy surfaces of HIPOwere optimized using DFT method PBE1PBE–D in conjunction with the 6-311++G (d,p) basis set.Vibrational frequency calculations were performed at the same level to obtain vibrational zero point andthermal energies and to validate the optimized structures as the energy-minima or transition states.

Keywords:

GSIPT , ESIPT , PBE1PBE