Dinitrobenzene ether reactive turn-on fluorescence probes for the selective detection of H2S

Two novel fluorescent probes, namely, 3-(2,4-dinitrophenoxy)-2-(4-(diphenylamino)phenyl)-4H-chromen-4-one (P1) and 3-(2,4-dinitrophenoxy)-2-(pyren-1-yl)-4H-chromen-4-one (P2), were designed and synthesized here. The probes (P1 and P2) were found to be highly selective and sensitive toward hydrogen sulfide (H2S) in the presence of a wide range of anions. The new probes (P1 and P2) were fully characterized by analytical, NMR spectroscopy (H-1 and C-13), and ESI mass spectrometry. The sensing capability of chemodosimeters (P1 and P2) toward H2S was confirmed by fluorescence studies. The 'turn-on' fluorescence was used to calculate the detection limit of probes (LOD), which were found to be 2.4 and 1.2 mu M for P1 and P2, respectively. Moreover, the probes were tested for their cytotoxicity against HeLa cells using the MTT assay and found to be non-cytotoxic in nature; hence, the probes P1 and P2 were successfully utilized to visualize H2S in the living cells.