A novel fluoride ion colorimetric chemosensor based on coumarin

A novel visible colorimetric sensor (L1) with high selectivity for fluoride ion based on coumarin has been synthesized by a simple modification of our earlier report. The chemosensor L1 shows an obvious color change from yellow to blue upon addition of fluoride ion with a large red shift of 145 nm in acetonitrile, and without interference of other anions such as Cl−, Br−, I−, NO3−, H2PO4−, HSO4−, and AcO−. The investigation of 1H NMR spectrum titration indicates the proposed mechanism is that F− first establishes a hydrogen bonding interaction with L1, and then the formation of [F–H–F]− induces deprotonation.

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► We report a novel visible colorimetric chemosensor L1 based on our previous works.
► L1 shows an obvious color change from yellow to blue upon addition of fluoride ion.
► L1 exhibits highly selective recognition of fluoride ion via the N–H deprotonation.