121st General Meeting of the KCS

Type Poster Presentation
Area Physical Chemistry
Room No. Event Hall
Time 4월 20일 (금요일) 11:00~12:30
Code PHYS.P-88
Subject Assignment for a Reaction Coordinate of Excited-State intramolecular Proton Transfer in HBQ
Authors Wooseok Heo, Taiha Joo*
Department of Chemistry, Pohang University of Science and Technology, Korea
Abstract Assignment of reaction coordinate has been a subject of extensive investigations. Here we report excited-state intramolecular proton transfer dynamics of 10-hydroxybenzo[h]quinolone (HBQ) in solution by time-resolved fluorescence (TF) and ab initio calculation. The excited-state intramolecular proton transfer (ESIPT) is prototype of excited-state reaction. HBQ is one of the most prominent ESIPT system via a pre-existing six-membered ring hydrogen bond configuration, and its rate is exceedingly fast (~20 fs). Highly time-resolved fluorescence measurement allows acquisition of accurate reaction kinetics. Upon photoexcitation of 10-aminobenzo[h]quinolone (ABQ) and its derivatives, the proton is transferred in different reaction depending on capability of an electron withdrawing group attached to a proton donor. Coherent wave packet motions of the product (tautomer) enable acquisition of the vibrational spectra of excited-state via TF (VETF). Comparison of the VETFs of the product and calculation of the Huang-Rhys factors (vibrational reorganization energy) identifies the vibrational mode that actively participate the coherent proton transfer. In particular, the 393 cm-1 vibrational mode, which consists of deformation and bending motion of backbone, promotes the ESIPT by transferring the proton donor and acceptor.
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