Turn-On Fluorescent Sensor for Selective Detection of Zn2+, Cd2+, and Hg2+ in Water

A new fluorescent chemosensor based on a helical imide as fluorophore and a cyclen moiety as ionophore was synthesized, which not only showed enhanced fluorescent responses in the presence of Zn2+, Cd2+, and Hg2+ but also could simultaneously and selectively distinguish the three cations in a simulated physiological condition with the help of cysteine as an auxiliary reagent.