Highly selective fluorescence turn-on sensor for hydrogen sulfide and imaging in living cells

A displacement method of detecting hydrogen sulfide in aqueous media based on complex L–Cu ensemble is developed. Once combined with Cu2+, complex L–Cu displayed high specificity for sulfide anion. Among the various anions, only sulfide anion induce the revival of fluoresecence of compound L, which is quenched by Cu2+, resulting in turn-on type sensing sulfide anion. Complex L–Cu exhibits a highly sensitive fluorescent response toward S2− by releasing compound L to give a remarkable change with 20-fold fluorescence intensity enhancement under 2 equivalent of S2− added in Tris–HCl/ DMF (20 mM, 6/4, v/v), and also exhibits a dynamic response range for S2− from 5×10−7 to 5×10−6 M, with a detection limit of 0.18 μM. In addition, the turn-on fluorescent change upon the addition of S2− is also applied in cell imaging.