Synthesis, Structure, and Properties of Rare-Earth Complexes Based on Pyridine Dicarboxylic Acid Ligands

The 2,6-lutidine-3,5-dicarboxylic acid (H2L1) was used as the main ligand, 1,10-phenanthroline (L-2) as the auxiliary ligand, and the complexes [Dy-2(L-1)(3)(L-2)(2)] (n) (1), {[Tb-2(L-1)(3)(L-2)(2)]center dot 5H(2)O} n (2), and {[Eu-2(L-1)(3)(L-2)(2)]center dot 5H(2)O} n ( 3) were synthesized by solvothermal reaction with dysprosium nitrate pentahydrate, terbium nitrate hexahydrate, and europium nitrate hexahydrate, respectively. The structures and properties of the complexes were characterized by single-crystal X-ray diffraction, IR, fluorescence spectroscopy, and thermogravimetric analysis. The results show that complexes 1-3 all use rare-earth ions as metal nodes to connect with ligands L-1(2-) and L-2 to form an infinitely extending 1D chain structure. CCDC: 2107136, 1; 2109709, 2; 2109716, 3.