A series of novel lanthanide carboxyphosphonates with a 3D framework structure: synthesis, structure, and luminescent and magnetic properties

By introduction of 1,4-benzenedicarboxylic acid as the second organic ligand, a series of novel lanthanide carboxyphosphonates with a 3D framework structure, namely, [Ln3(H2L)(HL)2(bdc)2(H2O)]·7H2O (Ln = La (1), Ce (2), Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), Tb (8); H3L = H2O3PCH2NC5H9COOH; H2bdc = HOOCC6H4COOH) have been synthesized under hydrothermal conditions. Compounds 1–8 are isostructural and feature a 3D framework in which Ln(III) polyhedra are interconnected by bridging {CPO3} tetrahedra into 2D inorganic layers parallel to the ab plane. The organic groups of H2L− are grafted on the two sides of the layer. These layers are further cross-linked by the bdc2− ligands from one layer to the Ln atoms from the other into a pillared-layered architecture with one-dimensional channel system along the a axis. The thermal stability of compounds 1–8 has been investigated. Luminescent properties of compounds 5–8, and the magnetic properties of compound 8 have also been studied.