Fluorescent triazolium for sensing fluoride anions in semi-aqueous solution

Abstract

A new pyrene-appended triazolium has been synthesized and explored as a highly efficient receptor for fluoride anions. In an CH₃CN–H₂O competitive solution, this probe shows an exclusive fluorescence turn-off sensing of F⁻ over other anions. ¹H NMR titrations and density functional theory (DFT) calculations revealed that the triazolium (CH)⁺, sulfonamide NH and pyrenyl CH donors were involved in hydrogen bonding interactions with a F⁻ anion to form a stable 1–F⁻ complex. In addition, the probe was successfully applied to the detection of F⁻ from inorganic origins in the solid state.