Excimer-monomer switch: a reaction-based approach for selective detection of fluoride

A N-aryl-1,8-naphthalimide based sensor (ES-1) bearing a trimethylsilyl ether has been synthesized by a two-step reaction for quantitative detection of fluoride (F-). ES-1 exhibited monomer/excimer emissions at 410 and 524 nm respectively in CH2Cl2. In the presence of F-, the desilylation of trimethylsilyl ether caused decay of the excimer emission as well as enhancement of the monomer emission to give a ratiometric signal. The fluoride-triggered desilylation showed a high reaction rate and high affinity to F- over nine other interfering anions. ES-1 provided a novel fluorescence assay based on excimer-monomer switch of N-aryl-1,8-naphthalimide to quantitatively measure F- with a detection limit of 0.133 ppm.