Synthesis, crystal structures and properties of two supramolecular polymers constructed by lanthanide with pyridine-2,4,6-tricarboxylic acid

Two lanthanide pyridine-2,4,6-tricarboxylate coordination polymers [Ln2(H2O)9(ptc)2]·3H2O (Ln = Dy(1), Yb(2); H3ptc = pyridine-2,4,6-tricarboxylic acid) have been synthesized and structurally characterized by single-crystal X-ray diffraction. The compound 1 and 2 is isostructural, and the feature of structure is a centrosymmetric tetra-nuclear unit, which is assembled into a 3D supra-molecular architecture via extensively hydrogen bonding interaction. The luminescence experiments show that compound 1 exhibit the typical luminescence of Dy3+ ion in the visible region. Besides luminescence, the magnetic properties of 1 and 2 were investigated and indicated the anti-ferromagnetic couplings between the Ln(III) ions.