A novel colorimetric fluorescent chemosensor for HSO4- using BODIPY-based Schiff base (L) has been developed. L is capable of showing high selectivity and sensitivity toward HSO4- over a wide range of other interfering anions. In presence of HSO4-, L shows a significant blue-shift in the absorption spectra from 523 to 497 nm and an increase of the ratio of the absorbance at 497 and 523 nm (A497/A523) over 150-fold, which induces color changes from pink to yellow. Non-fluorescent L upon interaction with HSO4- ions displays a 114-fold fluorescence enhancement at 533 nm, resulting in strong green emission. The binding mode of L with HSO4- has been investigated by Job's plot, 1H NMR and HRMS measurements. The sensing mechanism is suggested to proceed via a hydrolysis process. In addition, the cell imaging experiments demonstrate that L can be successfully applied as a bioimaging agent for monitoring HSO4- in HeLa cells.
Wang, L., Ou, J., Fang, G., & Cao, D. (2016). A fluorescent turn-on probe for detection of HSO4- ion based on hydrolysis of BODIPY-derived Schiff base with chromogenic and fluorogenic dual signals. Sensors and Actuators, B: Chemical, 222, 1184–1192. https://doi.org/10.1016/j.snb.2015.08.008