A new sensor based on thieno[2,3-b]quinoline for the detection of In3+ , Fe3+ and F- by different fluorescence behaviors.

Based on thieno[2,3-b]quinoline-2-carbohydrazide and salicylaldehyde, a novel fluorescent probe (L) was designed and synthesized. L could be used as a multifunctional sensor to sequentially detect In3+ and Fe3+ through fluorescence enhancement and fluorescence quenching in DMF/H2 O buffer solutions. At the same time, L had good anti-interference ability, which could still detect In3+ and Fe3+ well in the presence of other metal ions. For F- , it could be detected by enhancing the fluorescence change caused by the introduction of Al3+ . When other anions were present, the detection of F- would not be interfered. The detection limits of In3+ , Fe3+ and F- were 1.16×10-10 M, 2.03×10-8 M and 7.98×10-9 M, respectively. The complexation model and sensing mechanism between L and In3+ , Fe3+ and F- were confirmed by calculating structural optimization and energy optimization using Gaussian 09 software.