Four new lanthanide-organic frameworks: selective luminescent sensing and magnetic properties

Four new isostructural lanthanide-organic frameworks, [Ln(L)(H2O)(2)]center dot H2O center dot CH3CN (1-Ln) (Ln = Eu, Tb, Dy, and Gd), have been successfully synthesized via solvothermal reactions with a semi-rigid V-shaped multicarboxylate ligand 2-(2',4'-dicarboxylphenoxy) benzoic acid (H3L) and Ln(NO3)(3)center dot 6H(2)O. 1-Ln shows 2D layer-by-layer frameworks with interlayer channels decorated by carboxylate groups. 1-Eu exhibits excellent luminescence properties, and therefore, is chosen as a probe for sensing different metal ions and anions. Consequently, 1-Eu displays high selectivity and sensitivity for Fe3+ and Cr6+ ions, simultaneously, through the luminescence quenching effect, and thus, should be an excellent candidate for probing these pollutant metal ions. In addition, antiferromagnetic exchange interactions also exist between the Dy3+ ions in 1-Dy.