A naked eye fluorescent chemosensor for Zn2+ based on triphenylamine derivative and its bioimaging in live cells

Abstract A novel Zn 2+ fluorescent probe N ʹ-((4′-(diphenylamino)-4-hydroxy-[1,1′-biphenyl]-3-yl)methylene)-2-hydroxybenzohydrazide (TPA-HPH) with a larger Stokes shift (210 nm) was designed and synthesized, which was seen to be highly selective and sensitive to Zn 2+ ion over other metal ions in the system of MeCN:H 2 O (V/V = 6:4, pH = 7.0). Meanwhile, it was observed that the TPA-HPH solution changed from colorless to yellow by “naked eye” when Zn 2+ was added. Under optimized conditions, the fluorescence intensity of the probe showed a good linear relationship with Zn 2+ ion concentration in the range of 0–10 μM with a low detection limit of 7.3 × 10 −10  M. The fluorescent mechanism was proposed. Most importantly, TPA-HPH could realize on-site monitor and live cell imaging for Zn 2+ ion. Graphic abstract