Highly Sensitive and Selective Chemosensor for Cu2+ Based on a Schiff Base

A new chemosensor based on a Schiff base has been designed and synthesized. Its sensing behavior toward various metal ions was investigated by fluorescence and UV-Vis spectroscopic methods. The fluorescence of the sensor was quenched and the color rapidly changed from canary yellow to brown after the addition of Cu²⁺, while no changes occurred after the addition of other metal ions, which contributes to the detection of Cu²⁺ with naked eyes. The fluorescence quantum yield of the ligand was calculated to be 0.52. The corresponding detection limit of Cu²⁺ was 5.721×10^-7 mol/L, and the 1:1 binding mode of the sensor with Cu²⁺ was revealed by Job's plot.