Different Effect in the Selective Detection of Aniline and Fe3+ by Lanthanide-Based Coordination Polymers Containing Multiple Reactive Sites

In this paper, three isostructural 1D lanthanide complexes, [Ln(dppc)(H2O)4]n·2nH2O (Ln = Eu, Tb and Eu0.5Tb0.5, named as 1-Eu, 2-Tb and Eu0.5Tb0.5) based on 3-(2,4-dicarboxylate phenyl)-2-pyridinecarboxylic acid (H3dppc) have been synthesized and characterized by element analysis, IR, PXRD, TG and X-ray crystallography. The complexes exhibit 1D chain structure, which is further linked into 3D supramolecular framework by hydrogen bonds. Tuneable emission colour of Eu0.5Tb0.5 is realized by adjusting the excitation wavelength. Sensing properties of 1-Eu and 2-Tb towards Fe3+ and aniline indicate that the two complexes have almost the same superior sensitivity and low detection limit for Fe3+ aqueous solution, while have different detection ability for aniline in DMF solvent. The different detection effect was discussed by the means of PXRD, UV-vis, luminescent lifetime and molecular surface calculation (Hirshfeld surface analysis and 2D fingerprint plots).