New fluorescent sensor for Cu2+ and S2− in 100% aqueous solution based on displacement approach

An On–Off–On type fluorescent sensor (HL) has been developed, which exhibited high selectivity and sensitivity for Cu2+ over other common ions in 100% aqueous solution. Once HL combined with Cu2+, blue fluorescence was almost completely quenched and the L-Cu ensemble was formed. Moreover, the ensemble showed high specificity for S2− based on the displacement approach, and no interferences were observed in the presence of other anions. Such fluorescence modulation behavior simulates the performance of an IMPLICATION logic gate. In addition, the fluorescent sensor was successfully applied to fluorescent cellular imaging implying potential applications in physiological and environmental systems.