Highly sensitive and selective naked eye detection of fluoride anion with isatin-thiazole hybrid molecule

[Display omitted] •Synthesis of isatin-thiazole hybrid molecule.•Highly selective and sensitive fluoride anion sensor.•Dramatic color change from pale yellow to violet by naked-eye experiments.•Recognition and titration studies by UV/Vis spectroscopic technique.•1H NMR titrations shows deprotonation mechanism. The development of simple and cheap sensors/receptors for anion recognition is research area of immense importance in supramolecular chemistry. Among various artificial receptors, the compounds that preferably show visible color changes upon interaction with anions are particularly fascinating. We have designed and synthesized a novel isatin-thiazol hybrid molecule 2 that is found to be a highly selective and sensitive sensor for fluoride anion over the other anions such as Cl−, Br−, I−, PF4−, AcO−, ClO4−, H2PO4− as revealed by the UV–vis and naked eye experiments. The limit of detection (LOD) calculated for this sensor is 0.0044 ppm.