Multi-Fluorinated Azido Coumarins for Rapid and Selective Detection of Biological H2 S in Living Cells

Hydrogen sulfide (H2 S) is an endogenously produced gaseous signaling molecule with multiple biological functions. In order to visualize the endogenous in situ production of H2 S in living cells in real time, here we developed multi-fluorinated azido coumarins as fluorescent probes for the rapid and selective detection of biological H2 S. Kinetic studies indicated that an increase in fluorine substitution leads to an increased rate of H2 S-mediated reduction reaction, which is also supported by our theoretical calculations. To our delight, tetra-fluorinated coumarin 1 could react with H2 S fast (t1/2 ≈1 min) and selectively, which could be further used for continuous enzymatic assays and for visualization of intracellular H2 S. Bioimaging results obtained with 1 revealed that d-Cys could induce a higher level of endogenous H2 S production than l-Cys in a time-dependent manner in living cell.