A fluorescent off-on NBD-probe for F(-) sensing: theoretical validation and experimental studies.

The design, synthesis and fluoride sensing ability of a 7-nitro-2,1,3-benzoxadiazole (NBD) based chemodosimeter is reported. Theoretical calculations were used to design a more applicable off-on response, by choosing NBD as the accurate fluorophore. Reaction of the NBD-probe with 300 equivalents of tetrabutyl ammonium fluoride (TBAF) exhibited a response time of 80 minutes and the reaction was selective to F(-) and sensing of the ion was marked by a 110-fold enhancement of green fluorescence. The off-on fluorescence characteristics of the probe enabled its application in live-cell imaging of intracellular F(-) ions.