Reaction-based sensing of fluoride ions using desilylation method for triggering excited-state intramolecular proton transfer

The selectivity of NBT has been explored based on combination of desilylation reaction and modulation of the excited-state intramolecular proton transfer (ESIPT) from the desilylation product to F − . The method exhibited a high selectivity and a great sensitivity toward fluoride anions through ‘turn-on’ chromogenic activity and sensitivity.

The structure of HNBT has been established by single-crystal XRD. Density functional theory and TDDFT calculations were performed in order to demonstrate the electronic properties of HNBT, NBT and their anion. Upon treatment with fluoride in aqueous CH 3 CN solution, the TBS protective group of probe NBT was removed readily and ESIPT of the probe was switched on, which resulted in a decrease of the emission band at 415 nm and an increase in a new fluorescence peak around 586 nm.