Three novel lanthanide complexes with imidazole-4,5-dicarboxylate ligand: Hydrothermal syntheses, structural characterization, and properties

Three novel lanthanide complexes, namely, [Ce(Himdc)(H2imdc)(H2O)3]·H2O (1), {[Dy(Himdc)(Ox)0.5(H2O)2]·H2O}n (2), and {[Nd(Himdc)(Ox)0.5(H2O)2]·H2O}n (3) (H3imdc = imidazole-4,5-dicarboxylic acid, Ox = oxalate), have been successfully prepared by the assembly of lanthanide ions and H3imdc ligand under different synthetic conditions. All of the complexes have been characterized by means of elemental analysis, IR, TG analysis, luminescence spectroscopy as well as single-crystal X-ray diffraction analysis. The 3D supramolecular structure of 1 is constructed from 1D zig-zag chains through the hydrogen bonding interactions. Complex 2 possesses the chair-shaped secondary building units (SBUs) with Dy6(Himdc)4(Ox)2 and meso-helical chains (P + M), resulting in a novel 2D structure based on the linkages of oxalate ligand. Complex 3 also presents 2D layer structure with uninodal 6-connected net topology, but crystallizes in the different space group and owns higher coordination number of the central metal atom than complex 2. The luminescence property of 2 is investigated in the solid state at room temperature.