Highly sensitive and selective fluorescent sensor for Zn2+/Cu2+ and new approach for sensing Cu2+ by central metal displacement

An off-on'' Zn2+ and on-off'' Cu2+ fluorescent chemosensor C was designed and synthesized. The binding of C and Zn2+/Cu2+ is chemically reversible by the addition of EDTA disodium solution; moreover, the fluorescence emission signal of ZnC decreased with the addition of Cu2+, demonstrating that ZnC could detect Cu2+ via metal displacement.