Fluorescence sensors for Zn2+ based on conjugated indole Schiff base

•Two novel fluorescence probes were designed and synthesized.•Experiments and theoretical calculations showed that compounds have outstanding fluorescence properties.•The probes exhibited excellent sensitivity and selectivity for Zn2+.

Two novel fluorescence probes based on conjugated Schiff base for the detection of Zn2+ were developed. Corresponding molecular geometries, orbital energies, electron contributions and absorption properties of the fluorescence probes were calculated at B3LYP/6-31G∗ by density functional theory. The fluorescence properties of the probes were investigated by UV–vis and fluorescence spectrometer. Results indicate that the probes exhibit excellent sensitivity and selectivity for Zn2+ compared with metal ions examined. For example, the enhancement efficiency of the compound 2 for Zn2+ is up to 846%. The detection limit of the sensor toward Zn2+ could low to 1.0 × 10−7 M. Moreover, mechanisms for the high selectivity and sensitivity of the probes to Zn2+ were studied.

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