A Highly Selective Turn-On Fluorescent Probe for the Detection of Zinc

A novel turn-on fluorescence probe L has been designed that exhibits high selectivity and sensitivity with a detection limit of 9.53 × 10(−8) mol/L for the quantification of Zn(2+). (1)H-NMR spectroscopy and single crystal X-ray diffraction analysis revealed the unsymmetrical nature of the structure of the Schiff base probe L. An emission titration experiment in the presence of different molar fractions of Zn(2+) was used to perform a Job’s plot analysis. The results showed that the stoichiometric ratio of the complex formed by L and Zn(2+) was 1:1. Moreover, the molecular structure of the mononuclear Cu complex reveals one ligand L coordinates with one Cu atom in the asymmetric unit. On adding CuCl(2) to the ZnCl(2)/L system, a Cu-Zn complex was formed and a strong quenching behavior was observed, which inferred that the Cu(2+) displaced Zn(2+) to coordinate with the imine nitrogen atoms and hydroxyl oxygen atoms of probe L.