点击次数：

论文类型：期刊论文

发表时间：2018-07-21

发表刊物：NEW JOURNAL OF CHEMISTRY

收录刊物：SCIE

卷号：42

期号：14

页面范围：11804-11810

ISSN号：1144-0546

摘要：The dual-luminescence mechanism of the tetrasubstituted imidazole core (TIC) compound was theoretically explored by considering the excited-state intramolecular proton transfer (ESIPT) process in the present study. Density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods have been employed to gain the geometrical conformations, electronic transitions, frontier molecular orbitals (FMOs) and various spectra in different electronic states. An intramolecular hydrogen bond O-HN was observed for the TIC in the S-0 state. Upon electronic excitation, the TIC molecule is predominantly excited to the S-1 state as well as to an isosbestic point in the S-2 state. There is a twisted intramolecular charge transfer (TICT) during the S-0 S-1 (-*) transition and an intramolecular charge transfer (ICT) during the S-0 S-2 (-*) transition. The intramolecular hydrogen bond becomes stronger in the S-1 state than in the S-0 state. This leads to a strong fluorescence emission at 461 nm. However, the calculated potential curves showed that the intramolecular hydrogen bond O-HN transforms into OH-N in the S-2 state after the ESIPT reaction. A keto form of TIC is generated which gives rise to the other fluorescence emission at 575 nm through an ultrafast internal conversion (IC) process. This study aims to provide theoretical insights into the development of efficient chemosensors which are switched on through the ESIPT process.