A chemosensor bearing sulfonyl azide moieties for selective chromo-fluorogenic hydrogen sulfide recognition in aqueous media and in living cells

A simple chemodosimeter based on a sulfonyl azide dye (1-Az), which displayed a highly selective response toward hydrogen sulfide anion in mixed aqueous media, was synthesised and characterised. Addition of hydrogen sulfide to acetonitrile/HEPES 1:1 solutions of 1-Az induced a clear colour change from red-orange to yellow, which was easily detected by the naked eye, and by an enhancement in the emission intensity. Other common anions, thiol-containing biomolecules and oxidants did not induce any noticeable colour or fluorescence modulation in the probe. The chemodosimeter also showed a good sensitivity, with limits of detection of 11.91 and 0.63 μm by using UV/Vis or fluorescence measurements, respectively. Moreover, 1-Az could be used for real-time fluorescence imaging of intracellular HS at micromolar concentrations.
The authors thank the Spanish Government (project MAT2012-38429-C04-01), the Generalitat Valenciana (project PROMETEO/2009/016) and CIBER de Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN) for their support. The authors are also grateful to Fundacion Carolina and UPNFM Honduras (doctoral grant to L. E. S.-F.) and the Generalitat Valenciana for Santiago Grisolia (fellowship to S. E. S.).