Supramolecular architectures from the self-assembly of lanthanide ions with 6-hydroxypicolinic acid and 1,10-phenanthroline

Three new lanthanide complexes, [La(HpicO)3(phen)(H2O)]n (1) and Ln3(picO)4(phen)3(H2O)2·HpicO·0.5H2O (Ln=Er (2), Yb (3)) were synthesized by the hydrothermal reactions and characterized by single crystal X-ray diffraction, elemental analysis and IR spectrum. In complex 1, each La(III) ion is 10-coordinated and HpicO− ligands link the metal ions into 1D zigzag chains. Complexes 2 and 3 are isomorphous, and there are three crystallographically independent Ln(III) ions in the asymmetric unit. The N-H⋯O and O-H⋯O hydrogen bonds and π-π stacking interactions in these complexes result in the formation of 3D supramolecular architectures.