A highly sensitive fluorescent probe with different responses to Cu2+ and Zn2+

Abstract We report a highly sensitive fluorescent probe based on p -dimethylaminobenzoyl derivatives (probe L ) for the detection of Cu 2+ and Zn 2+ . In this work, the probe L exhibited a fluorescent turn-on sensing model to Cu 2+ and Zn 2+ with a distinct fluorescent color change from colorless to green and yellow respectively. Probe L exhibited high selectivity as a fluorescent Cu 2+ /Zn 2+ probe with a limit of detection (LOD) of 45 nM/17 nM. The results of 1 H NMR titrations revealed that the response of L to Cu 2+ and Zn 2+ was triggered by the interaction of the thiophene unit and the metal ion. Furthermore, the fluorescence titrations and Job's plot curves displayed the binding ratio of 1:2 for Cu 2+ and 1:1 for Zn 2+ metal- L complex formation respectively. Density functional theory calculation also demonstrated the possibility of molecular luminescence and the process of metal- L complex formation. Additionally, fluorescent test strips have been prepared for convenient detection of Cu 2+ and Zn 2+ , which means the convenient and rapid assay in real samples can be achieved.