Hydrogen Sulfide-Activatable Fluorescence Turn-On Triphenylamine Derivative and Its Application in Real Samples

A practical and highly selective reactive probe for hydrogen sulfide (H₂S), designated as 4-(7-(4-((7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)oxy)phenyl)benzo[c][1,2,5]thiadiazol-4-yl)-N,N-diphenylaniline (BTD), was synthesized through the covalent attachment of the 4-chloro-7-nitro-1,2,3-benzoxadiazole (NBD-Cl) unit to 4-(7-(4-(diphenylamino)phenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenol (BP-OH). The structure of probe BTD was characterized using IR, NMR, and HRMS. Experimental results demonstrate that the fluorescence of BTD significantly increases upon the introduction of H₂S, resulting in a distinct color change from colorless to bright orange-red. The detection capability of BTD for H₂S was assessed using UV-visible absorption and fluorescence emission spectroscopy. The probe shows significant fluorescence enhancement and can detect H₂S quantitatively over a concentration range of 0 to 14 μM, with a low detection limit of 44.85 nM. Furthermore, BTD exhibits excellent recovery rates and accuracy, indicating its practicality for H₂S analysis in real samples.