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)] center dot 3H(2)O}(n) (Ln1 = Nd (1), Sm (2)), {[Eu-2(HMIDC)(2)(C2O4)(H2O)(3)] center dot 0.5EtOH center dot 3H(2)O}(n) (3), {[Ce-2(HMIDC)(2) (C2O4)(H2O)(3)] center dot EtOH center dot 3H(2)O}(n) (4), and {[Gd-2(HMIDC)(2)(C2O4)(H2O)(3)] center dot MeOH center dot 3H(2)O}(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.