caa a22 4500 606181091 CHVBK 20210128100809.0 cr unu---uuuuu 210128e20151101xx s 000 0 eng 10.1007/s10876-015-0893-7 doi (NATIONALLICENCE)springer-10.1007/s10876-015-0893-7 Excited-State Intramolecular Proton Transfer Reaction of 3-Hydroxyflavone [Elektronische Daten] [Yanxue Jiang, Yajing Peng] The excited-state intramolecular proton transfer (ESIPT) reaction of 3-hydroxyflavone (3-HF) in methylcyclohexane solvent has been investigated by using the DFT and TD-DFT methods. The geometric structure, IR vibrational spectra, frontier molecular orbitals, natural bond orbital, and potential energy curves in the ground state (S0) and first excited state (S1) are analyzed to reveal the mechanism of proton transfer. The results demonstrate that there are enol- and keto- two isomers for 3-HF in the S1, which is accorded with the experimental double fluorescence bands. The 3-HF-enol can be isomerized into 3-HF-keto via ESIPT. The mechanism of proton transfer is attributed to the strengthening of hydrogen bond originated from intramolecular charge transfer. The potential energy curves in the S0 and S1 states also illuminate the tautomerism mechanism between 3-HF-enol and 3-HF-keto, and the ground-state 3-HF-keto might not exist long and is isomerized mostly into the 3-HF-enol due to its high energy or instability. This is the reason that only one absorption peak is observed for 3-HF in experiment. Springer Science+Business Media New York, 2015 TD-DFT nationallicence Infrared spectra nationallicence Frontier molecular orbitals nationallicence Excited-state intramolecular proton transfer nationallicence Potential energy curves nationallicence Jiang Yanxue Academy of Mathematics and Physics, Department of Physics, Bohai University, 121013, Jinzhou, China aut Peng Yajing Academy of Mathematics and Physics, Department of Physics, Bohai University, 121013, Jinzhou, China aut Journal of Cluster Science Springer US; http://www.springer-ny.com 26/6(2015-11-01), 1983-1992 1040-7278 26:6<1983 2015 26 10876 https://doi.org/10.1007/s10876-015-0893-7 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10876-015-0893-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Jiang Yanxue Academy of Mathematics and Physics, Department of Physics, Bohai University, 121013, Jinzhou, China aut NATIONALLICENCE 700 1- Peng Yajing Academy of Mathematics and Physics, Department of Physics, Bohai University, 121013, Jinzhou, China aut NATIONALLICENCE 773 0- Journal of Cluster Science Springer US; http://www.springer-ny.com 26/6(2015-11-01), 1983-1992 1040-7278 26:6<1983 2015 26 10876