A dual-channel 'turn-on' fluorescent chemosensor for high selectivity and sensitivity detection of CN over bar based on a coumarin-Schiff base derivative in an aqueous system

Novel strategies still need to be proposed that can be used to identify and detect toxic environmental pollutants. In this paper, two channels of colorimetry and fluorescence 'turn-on' fluorescent probe 1 (7-hydroxy-8-[(2-hydroxy-phenylimino)- methyl]-4-methylbenzopyran-2-one) for the simple yet highly selective detection of CN over bar have been successfully designed and synthesized. Crystal features of probe 1 were defined using X-ray single crystal diffractometry. Probe 1 showed a strongly colorimetric and fluorescence response to CN over bar that induced obvious naked-eye colour changes in aqueous solution (DMSO/H2O, 3:1 v:v). In addition, probe 1 for CN over bar detection displayed low detection limits of 3.91 x 10(-8) M, which were significantly lower than the 1.9 x 10(-6) M maximum level specified by the World Health Organization (WHO) for potable water. The sensing mechanism for probe 1 was attributed to the deprotonation process as shown by H-1 NMR titration. Moreover, based on the visible colorimetry and fluorescence change for probe 1 to CN over bar , measurement was performed for simulated water samples containing CN over bar . This study provides a broad prospect for solving other pollution problems and promoting the design of new fluorescent materials.

Automated summary

In this study, novel strategies were proposed for the identification and detection of toxic environmental pollutants. A highly selective detection method using colorimetry and fluorescence 'turn-on' fluorescent probe 1 was successfully developed for CN over bar detection, with low detection limits and clear color changes. The sensing mechanism was attributed to the deprotonation process, showing great potential for solving pollution problems and promoting the design of new fluorescent materials.