A novel near-infrared fluorescent probe for highly selective recognition of hydrogen sulfide and imaging in living cells.

A novel near-infrared fluorescent probe (L) based on a 1,4-diethyl-1,2,3,4-tetrahydro-7H-pyrano[2,3-g]quinoxalin-7-one scaffold has been synthesized and characterized. Probe L displays highly selective and sensitive recognition to H2S over various anions and biological thiols with a large Stokes shift (125 nm) in THF/H2O (6/4, v/v, Tris-HCl 10 mM, pH = 7.4). This probe exhibits turn-on fluorescence for H2S through HS- induced thiolysis of dinitrophenyl ether. Confocal laser scanning micrographs of MCF-7 cells incubated with L confirm that L is cell-permeable and can successfully detect H2S in living cells.