A Phenylselenium-Substituted BODIPY Fluorescent Turn-off Probe for Fluorescence Imaging of Hydrogen Sulfide in Living Cells

Herein a phenylselenium-substituted BODIPY (<b>1</b>) fluorescent turn-off sensor was developed for the purpose to achieve excellent selectivity and sensitivity for H<sub>2</sub>S detection based on the substitution reaction of the phenylselenide group at the 3-position with H<sub>2</sub>S. The excess addition of hydrogen sulfide promoted further substitution of the phenylselenide group at the 5-position of the probe and was accompanied by a further decrease in fluorescence emission intensity. Sensor <b>1</b> demonstrated remarkable performance with 49-fold red color fluorescence intensity decrease at longer excitation wavelength, a low detection limit (0.0025 μM), and specific fluorescent response toward H<sub>2</sub>S over anions, biothiols, and other amino acids in neutral media. It showed no obvious cell toxicity and good membrane permeability, which was well exploited for intracellular H<sub>2</sub>S detection and imaging through fluorescence microscopy imaging.