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

Abstract

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.