A highly selective and sensitive fluorescent sensor for Cu2+ and its complex for successive sensing of cyanide via Cu2+ displacement approach

A new benzimidazole-based imine linked sensor (1) was synthesized. Sensor 1 exhibits highly selective and sensitive recognition properties to Cu2+ in CH3OH/H2O (1/1, v/v, HEPES 10 mM, pH = 7.0) solution with a 1:1 binding stoichiometry. The in situ prepared 1–Cu2+ complex solution displays high selectivity to cyanide through Cu2+ displacement approach and possesses excellent tolerance to other common interference anions. The detection limits of sensor 1 to Cu2+ and 1–Cu2+ complex to cyanide were estimated to be 1.82 × 10−8 M and 1.62 × 10−6 M, respectively. This Cu2+ and cyanide successive recognition feature of sensor 1 makes it a potential utility for Cu2+ and cyanide detection in aqueous media.