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Indexed by:期刊论文

Date of Publication:2019-01-15

Journal:SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY

Included Journals:SCIE、PubMed、Scopus

Volume:207

Page Number:61-67

ISSN No.:1386-1425

Key Words:Hydrogen bonds; ESIPT; Configuration twisting; Potential energy curves; Fluorescence

Abstract:The photophysical properties and photochemistry reactions of 2-(2-Hydroxy-phenyl)-4(3H)-quinazolinone (HPQ) system in different solutions are studied by using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. Our theoretical investigation explores that an ultrafast barrier-free excited state intramolecular proton transfer (ESIPT) process occurs and the configuration twisting is found in the electronic excited state. In the polar protic methanol solution, the hydrogen-bonded complex composed by HPQ and two methanol molecules (HPQ-2M) could exist stably in the ground state. Upon photoexcitation the isolated HPQ is initially excited to the first excited state, while the HPQ-2M system is firstly excited to the S-3 state and undergoes internal conversion (IC) to the S-1 state. The intermolecular hydrogen bonds are strengthened in the excited state. The simulated electronic spectra agree well with the experimental results. The strengthening of the intermolecular hydrogen bonds is also confirmed by the calculated vibrational spectra. In addition, the intramolecular charge transfer happens in both HPQand HPQ-2M systems from the frontier molecular orbital analysis. (C) 2018 Elsevier B.V. All rights reserved.