Highly selective red-emitting H2S fluorescent probe with a large Stokes shift

The O-2,4-dinitrobenzensulfonate of 1,3-bis(bispyridin-2ylimino)isoindolin-4-ol has been developed as a novel red-emitting fluorescent probe for the detection of H2S. The dinitrobenzenesulfonate moiety in the probe both prohibits the excited state intramolecular proton transfer process and produces a photoinduced electron transfer process, which renders the probe non-fluorescent in the absence of the analyte. In the presence of H2S a specific H2S-mediated cleavage reaction converts the probe into 1,3-bis(bispyridin-2-ylimino)isoindolin-4-ol which exhibits a strong red fluorescence with a large Stokes shift (218 am) via an excited state intramolecular proton transfer process upon excitation. It's noteworthy that this new probe shows good selectivity and sensitivity to H2S over glutathione, cysteine and homocysteine. Moreover successful detection and imaging of intracellular H2S in living cells was achieved. To our knowledge this is the first application of this type of fluorescent probe for intracellular H2S detection. (C) 2014 Elsevier Ltd. All rights reserved.