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Indexed by:期刊论文

Date of Publication:2010-08-01

Journal:JOURNAL OF LUMINESCENCE

Included Journals:SCIE、EI、Scopus

Volume:130

Issue:8

Page Number:1431-1436

ISSN No.:0022-2313

Key Words:Excited state intramolecular proton transfer; Hydrogen bonding; Proton transfer tautomer; 3-Hydroxy-2-(pyridin-2-yl)-4H-chromen-4-one

Abstract:The time-dependent density functional theory (TDDFT) method was carried out to investigate the excited state intramolecular proton transfer (ESIPT) process of 3-hydroxy-2-(pyridin-2-yl)-4H-chromen-4-one (1a). 1a has two tautomeric forms: one is 1a(O), which is induced by intramolecular hydrogen bond O-H center dot center dot center dot O=C, and the other one is 1a(N), which is caused by intramolecular hydrogen bond O-H center dot center dot center dot N. From excited state to tautomer excited state coming from ESIPT, the hydroxyl hydrogen breaks away and the dissociated hydrogen adsorbed on pyridinic nitrogen or carbonyl oxygen formed new intramolecular HB and the corresponding bond length and bond angle varied greatly. In comparison, a similar process of proton transfer for 1a(N)H(+). protonated 1a(N) from ground state to excited state was obtained. This detailed proton transfer mechanism was provided by molecular orbitals analysis and it may be applied to molecular switch and organic Lewis acid/base. We investigated the excited state proton transfer mechanism of the four molecules through the theoretical method for the first time and gave unambiguous geometry of excited state. (C) 2010 Elsevier B.V. All rights reserved.