An acylhydrazone coumarin as chemosensor for the detection of Ni2+ with excellent sensitivity and low LOD: Synthesis, DFT calculations and application in real water and living cells

A novel acylhydrazone coumarin fluorescent chemosensor C4 for detection of Ni2+ was designed and synthesized. The experimental results revealed a low detection limit of 2.1 × 10−11 M with high selectivity and excellent sensitivity towards Ni2+. C4 showed a good linear relationship with the concentration of Ni2+ from 1.3 × 10−6 to 1.6 μM. Moreover, a stable complex was formed between C4 and with Ni2+ and the binding ratio was proved to be 2: 1 by Job’s plot and mass spectrum. The sensing ability of C4 towards Ni2+ was attributed to parity-forbidden transition according to fluorescence titrations and DFT calculations. The detection of Ni2+ in water samples illustrated C4 could be successfully applied for the detection of Ni2+ in real environmental samples. What’s more, the fluorescence microscopy images of Hela cells demonstrated the high potential of the novel biosensor for the investigation of biological processes involving Ni2+, as well.