Lanthanide(iii) oxalatophosphonates: syntheses, crystal structures and luminescence properties

Abstract

By the introduction of oxalate as the second ligand, five new lanthanide oxalatophosphonate hybrids with a 2D layered structure, namely, [Ln(H₂L)(C₂O₄)(H₂O)]·2H₂O [Ln = Nd (1), Sm (2), Eu (3), Tb (4), Dy (5), H₃L = H₂O₃PCH₂NCH₂(CH₂CH₂OPO₂H)], have been hydrothermally synthesized and structurally characterized by X-ray single-crystal diffraction, X-ray powder diffraction, infrared spectroscopy, elemental analysis and thermogravimetric analysis. Compounds 1–5 are isostructural and exhibit a 2D layer formed by the interconnection of a 1D zigzag chain of {Ln(C₂O₄)}⁺ with the phosphonate ligands. The effect of lanthanide contraction induces the decrease of the lattice parameters and crystal size from Nd to Dy. The luminescence properties of compounds 2–5 have been studied.