A simple amide fluorescent sensor based on quinoline for selective and sensitive recognition of zinc(II) ions and bioimaging in living cells

A simple quinoline-based derivative (AQDPA) was developed as a highly efficient fluorescent sensor for sensing Zn ²⁺ and sequential recognition of pyrophosphate and sulfur ions. This chemosensor was synthesized from diisopropylamine and 2-chloro-N-(quinolin-8-yl)acetamide. The non-fluorescence sensor displayed significant and specific fluorescence enhancement after binding to Zn ²⁺ with high selectivity. The fluorescence titration analysis shows a detection limit for Zn ²⁺ at 4.1 × 10 ⁻⁸ M. The sensing mechanisms of AQDPA binding to Zn ²⁺ were supported by ¹ H NMR, HR-MS analysis, and density functional theory (DFT) study. Moreover, the fluorescence imaging in HeLa cells suggested that this simple sensor had great potential in the application of biological imaging.