First fluorescent sensor for curcumin in aqueous media based on acylhydrazone-bridged bis-tetraphenylethylene

This work designed and synthesized the first organic fluorescent sensor for curcumin in aqueous media based on red-to-green fluorescence change of acylhydrazone-bridged bis-tetraphenylethylene (Bis-TPE). Bis-TPE was prepared by condensation of formyltetraphenylethylene with dihydrazide oxalate in 86% yield. It has the large conjugated electron effect with strong red AIE fluorescence in aqueous solution. It displayed high selective sensing ability for curcumin with red-to-green fluorescence change in THF-H₂O (5:95). The detection limit was as low as 1.15 × 10^-7 M. The sensing mechanism was confirmed as 1:1 stoichiometric ratio based on quadruple hydrogen bonds. Bis-TPE was successfully applied for analyzing curcumin of ginger and living cell imaging, supplying a new detecting strategy for curcumin in real sample and living environment.