A new naphthalimide-picolinohydrazide derived fluorescent "turn-on" probe for hypersensitive detection of Al ions and applications of real water analysis and bio-imaging.

The development of high-selective chemosensors for trace Al detection in the ecosystem is crucially importance due to its detrimental effects. In this work, a simple Schiff-base fluorescent probe NPP derived from naphthalimide and picolinohydrazide was rationally designed and prepared for efficient detection of Al. NPP exhibited prominent sensing behaviors toward Al with low detection limit (LOD) (39 nM), rapid response time (1 min), strong binding affinity (4.02 × 10), good anti-interference characteristics and visual detection. Binding ratio of NPP-Al complex was determined to be 1:1 by Job's plot analysis. In addition, the chelation mechanism of NPP with Al ions was proposed and substantiated by the density functional theory (DFT) and time-dependent density functional theory (TD-DFT), IR spectrum and H NMR titration experiments. Furthermore, this "signal-on" probe NPP was efficiently utilized as a promising indicator for Al detection in environmental and biological samples.