title: TD-DFT study on the sensing mechanism of a fluorescent chemosensor for fluoride: excited-state proton transfer.
abstract: An excited-state proton transfer (ESPT) process, induced by both intermolecular and intramolecular hydrogen-bonding interactions, is proposed to account for the fluorescence sensing mechanism of a fluoride chemosensor, phenyl-1H-anthra(1,2-d)imidazole-6,11-dione. The time-dependent density functional theory (TD-DFT) method has been applied to investigate the different electronic states. The present theoretical study of this chemosensor, as well as its anion and fluoride complex, has been conducted with a view to monitoring its structural and photophysical properties. The proton of the chemosensor can shift to fluoride in the ground state but transfers from the proton donor (NH group) to a proton acceptor (neighboring carbonyl group) in the first singlet excited state. This may explain the observed red shifts in the fluorescence spectra in the relevant fluorescent sensing mechanism.
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
authors.forename: Guang-Yue
authors.initials: GY
authors.lastname: Li
authors.forename: Guang-Jiu
authors.initials: GJ
authors.lastname: Zhao
authors.forename: Yu-Hui
authors.initials: YH
authors.lastname: Liu
authors.forename: Ke-Li
authors.initials: KL
authors.lastname: Han
authors.forename: Guo-Zhong
authors.initials: GZ
authors.lastname: He
mesh_terms: D003198:Computer Simulation; D005456:Fluorescent Dyes / Q000032:analysis / Q000737:chemistry*; D005459:Fluorides / Q000032:analysis* / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D011522:Protons; D011789:Quantum Theory; D012984:Software; D013050:Spectrometry, Fluorescence; D013997:Time Factors; D014732:Vibration
chemical_list: D005456:Fluorescent Dyes; D011522:Protons; D005459:Fluorides