title: Synthesis and properties of fluorescence dyes: tetracyclic pyrazolo[3,4-b]pyridine-based coumarin chromophores with intramolecular charge transfer character.
abstract: Two series of new tetracyclic pyrazolo[3,4-b]pyridine-based coumarin chromophores were synthesized through a facile reaction between 3-aldehyde-7-diethylaminocoumarin (5) or 3-acetyl-7-diethylaminocoumarin (6) and 5-aminopyrazole derivatives (7) in a one-pot procedure. Different condensed products were obtained from compounds 5 and 6, and the potential reaction mechanism was studied using the reaction of 5 with 5-amino-1-phenylpyrazole (7a). The molecular structures were characterized by NMR and HRMS and confirmed by X-ray diffraction. The photophysical, electrochemical, and thermal properties of these compounds were investigated by absorption spectroscopy, fluorescence spectroscopy, single photon counting technique, cyclic voltammetry, thermogravimetric analysis, etc. Results show that the compounds exhibited high fluorescence quantum yields and good electrochemical, thermal, and photochemical stabilities. In addition, the application of these highly fluorescent compounds in living cell imaging was also explored by laser scanning confocal microscopy.
authors.affiliation: Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
authors.forename: Jianhong
authors.initials: J
authors.lastname: Chen
authors.forename: Weimin
authors.initials: W
authors.lastname: Liu
authors.forename: Jingjin
authors.initials: J
authors.lastname: Ma
authors.forename: Haitao
authors.initials: H
authors.lastname: Xu
authors.forename: Jiasheng
authors.initials: J
authors.lastname: Wu
authors.forename: Xianglin
authors.initials: X
authors.lastname: Tang
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Fan
authors.forename: Pengfei
authors.initials: P
authors.lastname: Wang