Comments on the paper “Excited state intramolecular proton transfer reaction revisited: S1 state or general reversibility?” by A.O. Doroshenko, A.Yu. Matsakov, O.V. Nevskii, O.V. Grygorovych [J. Photochem. Photobiol. A: Chem. 250 (2012) 40–49]

We cannot agree with the point of view [1] that in characteristics of dual fluorescence of flavones ESIPT reverse reaction is not actual and “simple test (suggested in our paper [2]) for the mechanism of excited-state reaction” does not confirm the ESIPT reaction reversibility. We present here our arguments and experimental results in favor of our position.

► In characteristics of dual fluorescence of flavones, ESIPT reverse reaction is actual. ► The contributions of the individual bands for the probes with overlapped spectra can be analyzed with sufficient accuracy. ► The ratio of band intensities does not exhibit a growth with the temperature quenching of fluorescence in reversible ESIPT.