Activatable colorimetric and fluorogenic probe for fluoride detection by oxazoloindole-to-hydroxyethylindolium transformation

In this study, we report a dual colorimetric and fluorogenic probe of latent fluorescence based on oxazoloindole functionalized silylphenyl ether for the selective detection of fluoride in aqueous solvent. The fluoride probe ( FP-1 ) underwent dramatic UV-vis and fluorescence changes in the presence of fluoride anions, displaying a highly selective and sensitive response to fluoride with a submicromolar limit of detection (LOD = 0.59 μM) in 20% aqueous acetonitrile solvent. When F − was added to FP-1 , the probe exhibited strong NIR fluorescence as well as a significant red color by the tetrahydrooxazoloindole-to-hydroxyethylindolium transformation, which was easily detectable by the naked eye. An oxazoloindole-based dual optical probe displayed a highly sensitive response to fluoride with dramatic UV-vis and fluorescence changes in aqueous solution.