A fluorescent “off-on-off” probe based on a new bis(salamo)-like compound for the sensitive and rapid detection of phosphates

•A new salamo-like compound H3L exhibits strong fluorescence response to Zn2+ions.•The complex sensor l-Zn2+ has high selectivity and sensitivity towards phosphates.•The sensor l-Zn2+ can detect phosphates in complex environments. A new bis(salamo)-like compound H3L was designed and synthesized. With the addition of Zn2+ ions to the H3L solution, the fluorescence intensity increased significantly and the color changed from blue-cyan to bright green. Based on ESI-MS, UV–Vis spectroscopy and DFT calculations, a plausible mechanism for the interaction of the compound H3L with Zn2+ ions is proposed. The in situ complex sensor l-Zn2+ formed by the coordination of the compound H3L with Zn2+ions has been used for various anion recognition. The results showed that the sensor l-Zn2+ has high selectivity and sensitivity to phosphates. The fluorescence experiments of the compound H3L and sensor l-Zn2+ at different pH values showed that fluorescence response is good in neutral and weak base environment. Simple test paper strips and the detection in real water samples were applied for the detection of phosphates in complex environment. A new salamo-like compound H3L was designed and synthesized. With the addition of Zn2+ ions to the H3L solution, the fluorescence intensity increased significantly and the color changed from blue-cyan to bright green. The in situ complex sensor l-Zn2+ formed by the coordination of the compound H3L with Zn2+ions has been used for phosphates recognition. [Display omitted]