A new Al selective fluorescent turn-on sensor based on hydrazide-naphthalic anhydride conjugate and its application in live cells imaging.

In this communication, we have developed an optical chemosensor 2-amino N-(6-bromo-1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)benzamide (NAPH) for selective detection of Al by reacting 4-bromo-1,8-naphthalic anhydride with 2-aminobenzohydrazide. In (DMSO:HO, 1:1, v/v) medium, the selective and specific nature of NAPH towards Al was observed by the quenching along with a blue-shift in the absorption of NAPH at 465 nm that resulted in the distinct colour change from light brown to colourless. The selective complexation that occurred between NAPH and Al was investigated by H NMR and DFT methods. Under similar conditions, the weakly fluorescent receptor NAPH showed a distinct fluorescence enhancement at 555 nm in the presence of Al among the other tested metal ions and anions. The NAPH·Al complex formation is reversible upon addition of strong chelating agent EDTA. The receptor NAPH can be applied to detect Al down to 2.9 μM without any interference from other tested metal ions. In addition, the receptor NAPH was successfully applied to detect Al in live HeLa cells.