Fluorescence sensors for Zn(2+) based on conjugated indole Schiff base

Two novel fluorescence probes based on conjugated Schiff base for the detection of Zn(2+) 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 Zn(2+) compared with metal ions examined. For example, the enhancement efficiency of the compound 2 for Zn(2+) is up to 846%. The detection limit of the sensor toward Zn(2+) could low to 1.0×10(-7)M. Moreover, mechanisms for the high selectivity and sensitivity of the probes to Zn(2+) were studied.