• Lanthanidecomplexes;
  • 3-D structure;
  • Pyridine-2,5-dicarboxylic acid;
  • Decarboxylation;
  • Magnetism;
  • Fluorescence


The hydrothermal reactions of Ln2O3 (Ln = Nd and Eu) with pyridine-2,5-dicarboxylic acid (H2pydc) resulted in the formation of two isomorphic three-dimensional (3D) polymeric LnIII complexes, [Ln(pydc)(nic)·H2O]n (Ln = Nd(1) and Eu(2)), in which nic (nicotinate; also named as pyridine-2-carboxylic acid) might have been formed from the pydc ligands through the C–C bond cleavage and CO2 molecules releasing. Pydc ligands bridge lanthanide centers to form the three-dimensional framework featuring hexagonal channels along the axis a which are occupied by bridging nic anions and mono-coordinated water molecules. From the topological point of view, two three-dimensional nets are binodal with six- and three-connected nodes, which display a distorted rutile (4.62)2(42·610·83) topology. Magnetic measurements (2-300 K) reveal that all polymers possess weak antiferromagnetic property. A strong fluorescence emission spectrum of compound 2 was observed.