Selective fluorescence detection of anilines and Fe3+ ions by two lanthanide metal–organic frameworks

Two isostructural lanthanide metal–organic frameworks [Ln2(TDC)3(CH3OH)2·(CH3OH)] (Ln = Eu, 1; Tb, 2, TDC = 2,5-thiophenedicarboxylic acid) were successfully synthesized. For the two compounds, the participation of the fluorescent ligand H2L sensitized and enhanced the lanthanide characteristic emissions of the two MOFs as expected. Luminescent investigations reveal that 1 and 2 can be efficient multifunctional luminescent materials for high-sensitivity sensing of aromatic amine compounds and metal ions, especially for p-nitroaniline and Fe3+ ions with a fluorescence quenching effect. Additionally, diphenylamine significantly enhanced the ligand-based emission of 2 under the same experimental conditions. These features make 1 and 2 promising candidates for the development of multifunctional sensors in the future.