Two types of lanthanide coordination polymers showing luminescence and magnetic properties

Abstract

Lanthanide coordination polymers (Ln-CPs) {[Ln(HL)2(H2O)3]·(H2O)4·Cl}n (Ln = Dy, 1; Eu, 2; Sm, 3) and [Ln0.18(HL)0.18(CH3COO)0.36(H2O)0.54]n (Ln = La, 4; H2L = 2-(hydroxymethyl)-1H-benzo[d]imidazole-5-carboxylic acid) have been successfully assembled by Ln3+ ions and asymmetric carboxylic acid ligand under solvothermal conditions. The structures of the complexes 1–4 were determined by single crystal X-ray diffraction and further characterized by elemental analyses, IR spectroscopy, powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA). The structure analysis display that complexes 1–3 are isostructural three-dimensional (3D) supramolecular network. Complexes 1–4 were constructed by hydrogen bonding interactions between the coordinated water molecules and the O atoms of the hydroxy group or free chloride ions. Furthermore, luminescence properties of complexes 1–4 have been measured in the solid state at room temperature. Complex 2 exhibits a strong red luminescence upon excitation at 283 nm and its lifetimes is 33.554 ns. In addition, magnetic studies reveal that complex 1 has a weak antiferromagnetic interaction.