A series of lanthanide-organic frameworks constructed by 2-methyl imidazole dicarboxylate and oxalate: synthesis, structures, and properties

Five lanthanide(III) coordination polymers with 2-methyl-1H-imidazole-4,5-dicarboxylic acid (H3MIDC) and ammonium oxalate, {[(Ln1)2(HMIDC)2(C2O4)(H2O)3] · 3H2O} n (Ln1 = Nd (1), Sm (2)), {[Eu2(HMIDC)2(C2O4)(H2O)3] · 0.5EtOH · 3H2O} n (3), {[Ce2(HMIDC)2(C2O4)(H2O)3] · EtOH · 3H2O} n (4), and {[Gd2(HMIDC)2(C2O4)(H2O)3] · MeOH · 3H2O} n (5), have been prepared and structurally characterized. Single-crystal X-ray diffraction analyses reveal that 1 and 2 are isostructural, as are 3, 4, and 5. Each exhibits a 3-D open framework, which is built by a regular 2-D grid connected by HMIDC2− and Ln(III). The luminescence and thermal properties of these complexes have been investigated as well.