A new fluorescent turn-on probe (I) for the selective sensing and bioimaging of thiols is reported. In aq. buffer solns. at physiol. pH, thiols cleave the 2,4-dinitrobenzenesulfonyl group to release the red-emissive donor-acceptor fluorophore. The probe displays excellent immunity to interference from nitrogen and oxygen nucleophiles and the imaging of thiols in living cells is demonstrated. [on SciFinder(R)]
