Development of a coumarin-based fluorescent probe for hydrogen peroxide based on the Payne/Dakin tandem reaction

Hydrogen peroxide (H2O2) is associated with many physiological and pathological processes in biological systems. Here, we report 7-diethylamino-3-formyl-coumarin (Cou-CHO) as a turn-on fluorescent probe for H2O2. The proposed probe employs a tandem Payne/Dakin reaction to convert the electron-withdrawing aldehyde to the electron-donating hydroxyl group, thus hindering the formation of twisted intramolecular charge transfer (TICT) state of 7-diethylaminocoumarin, and thereby resulting in a fluorescence turn-on response. Cou-CHO features high specificity, excellent sensitivity and fast response toward H2O2. In particular, Cou-CHO enables the direct visualization of basal and endogenously produced H2O2 in living cells. The results demonstrate that the tandem Payne/Dakin reaction can provide a new choice to develop H2O2-selective probes.