NBD-based colorimetric and fluorescent turn-on probes for hydrogen sulfide

Abstract

Hydrogen sulfide (H₂S) is an important endogenous signalling molecule and also an important environmental target for detection. New reaction-based colorimetric and fluorescent turn-on probes based on selective thiolyling of NBD (7-nitro-1,2,3-benzoxadiazole) ether were explored for sensing of H₂S in aqueous buffer. The syntheses of both probes are simple and quite straightforward. The probes are highly sensitive and selective toward H₂S over other biologically relevant species. Probe 1 can be used to directly visualize H₂S by the naked eye and shows more than 1000-fold fluorescence increase upon reaction with H₂S. Probe 2 is a near-infrared fluorescent sensor for H₂S at physiological pH.