AIE-based ratiometric fluorescent probe for mercury ion, medium-dependent fluorescence color change and optimized sensitivity in solid state.

A new AIE-based luminogen TPES, as a ratiometric fluorescence probe for mercury(II) was readily synthesized. The probe combined the advantages of the outstanding specificity of Hg-triggered deprotection reaction of thioketal and the brilliant emission of AIEgens in aggregated state. Once encountered aqueous Hg, fluorescent color of TPES in THF-HO (f = 98%) altered from blue to green rapidly, while other metal cations gave no interference to the probe. And the mechanism of this chemosensor was carefully verified by H NMR analysis, FTIR and MS spectra. As expected, TPES exhibits excellent selectivity and sensitivity towards Hg in the solid state. When using filter paper as the solid medium, the fabricated test strips could signify Hg ions with the LOD as 1 × 10 M (Hg in aqueous solution), accompanied with a distinct emitting altered from blue to green. Furthermore, by changing the medium from filter paper to silica gel plate, a more significant fluorescence alteration from blue to yellow was achieved, and the LOD was further optimized to 1 × 10 M as discerned by naked-eye.