Study of fluorescence probe transfer mechanism based on a new type of excited-state intramolecular proton transfer.
3-Hydroxyflavone (3-HF) is a typical representative of a new type of fluorescent molecular probe. The intramolecular proton transfer mechanisms of 3-HF and its derivatives have been studied theoretically based on detailed density functional theory. An optical physical cycle diagram of intramolecular proton transfer of 3-HF and its derivatives has been found based on the optimal configuration before and after proton transfer. An analysis of the absorption and fluorescence spectra of these probes explains their optical physical mechanism, which agrees well with experimental results. This correlation indicates that the adopted theory is reasonable and effective. The primary bond lengths, angles and infrared vibrational spectra indicate that the intramolecular hydrogen bonds were strengthened, which is an indication of the excited-state intramolecular proton transfer (ESIPT) processes. The constructed potential energy curves of the ground and first excited state based on these three chromophores provide the ESIPT mechanism, which demonstrates that potential barriers lower than the 6kcal/mol and justifies the ESIPT processes occur in the first excited state. The fluorescence quenching phenomenon has been explained based on the ESIPT mechanism.
Normal College, Shenyang University, Shenyang 110044, China.
Yumei
Y
Dai
College of Physics, Liaoning University, Shenyang 110036, China.
Jinfeng
J
Zhao
College of Physics, Liaoning University, Shenyang 110036, China.
Yanling
Y
Cui
College of Physics, Liaoning University, Shenyang 110036, China.
Qianyu
Q
Wang
College of Physics, Liaoning University, Shenyang 110036, China; Liaoning Key Laboratory of Semiconductor Light Emitting and Photocatalytic Materials, Liaoning University, Shenyang 110036, China. Electronic address: songpeng@lnu.edu.cn.
Peng
P
Song
College of Physics, Liaoning University, Shenyang 110036, China; Liaoning Key Laboratory of Semiconductor Light Emitting and Photocatalytic Materials, Liaoning University, Shenyang 110036, China. Electronic address: fcma@lnu.edu.cn.
Fengcai
F
Ma
Normal College, Shenyang University, Shenyang 110044, China.
Yangyang
Y
Zhao
D004583:Electrons; D005419:Flavonoids / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D011522:Protons; D013050:Spectrometry, Fluorescence; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics
D005419:Flavonoids; D005456:Fluorescent Dyes; D011522:Protons; C041477:3-hydroxyflavone
Density functional theory; Excited-state intramolecular proton transfer; Fluorescence probe; Hydrogen bond; Ultraviolet–visible