A novel quinoline derivative as dual chemosensor for selective sensing of Al3+ by fluorescent and Fe2+ by colorimetric methods

•A novel quinoline derivative chemosensor (QN) as dual chemosensor was designed, synthesized and characterized.•The chemosensor QN exhibits highly selectivity fluorescence enhancement to Al3+ and colorimetric sensing for Fe2+.•The plausible binding modes of QN-Al3+ and QN-Fe2+ were supported by theoretical calculations. A simple and novel quinoline derivative (QN), based on quinoline-8-carboxaldehyde and 3‑hydroxy-2-naphthoic hydrazide was synthesized. The structure of chemosensor QN was confirmed by X-ray Crystallography. The chemosensor QN as dual chemosensor showed selective fluorescence recognition of Al3+ and colorimetric detection of Fe2+. In the presence of Al3+, the sensor QN generated a noticeable fluorescence enhancement accompanied with obvious color change from colorless to yellowish green. Moreover, QN was successfully used for colorimetric sensing for Fe2+, while the solution color changed from pale yellow to dark green. The detection limit was obtained to be 1.22 × 10−8 mol L−1 for Al3+ and 1.04 × 10−7 mol L−1 for Fe2+. The sensing mechanism of sensor QN toward Al3+ and Fe2+ were investigated by 1H NMR, ESI-MS and IR. Moreover, the coordination modes of QN-Al3+ and QN-Fe2+were confirmed by theoretical calculations. [Display omitted]