A turn-on near-infrared fluorescent probe with rapid response and large Stokes shift for the selective and sensitive detection of zinc(II) and its application in living cells

Herein, a new near-infrared turn-on fluorescent probe, YPT, was designed and synthesized for the rapid detection of Zn²⁺, which exhibited low limit of detection for Zn²⁺ (12 nM) as well as a favorable large Stokes shift (λ_em − λ_ex = 168 nm). In addition, the probe showed rapid detection progress within 30 s, accompanied by a distinct change in fluorescence from colorless to bright red. Moreover, the sensing mechanism of YPT towards Zn²⁺ was supported by the Job's plot, HR-MS analysis, ¹H NMR titration analysis and density functional theory (DFT) results. In addition, YPT was applied as a visible test strip for the detection of Zn²⁺. Finally, the NIR fluorescence imaging of Zn²⁺ was successfully performed in living cells using this probe. All the results indicate that this probe can be used to detect Zn²⁺ in both solution and living systems.