Four cadmium(II) polymeric frameworks constructed by 2-methyl or 2-ethyl imidazole dicarboxylates

Four polymeric frameworks, {[Cd(HMIDC)(phen)]·H2O}n (1), {[Cd4(HMIDC)4]·8H2O}n (2), Cd(HMIDC)(2,2′-bipy)]n (3), and {[Cd(HEIDC)(2,2′-bipy)]2}n (4) (H3MIDC = 2-methyl-1H-imidazole-4,5-dicarboxylic acid, H3EIDC = 2-ethyl-1H-imidazole-4,5-dicarboxylic acid, phen = 1,10-phenanthroline, 2,2′-bipy = 2,2′-bipyridine) have been hydro(solvo)thermally synthesized and structurally characterized by single-crystal X-ray diffraction. Compounds 1, 3 and 4 are one-dimensional (1D) infinite chains, in which the HMIDC2− or HEIDC2− units as μ2-mode link the Cd(II) atoms with phen or 2,2′-bipy chelating the central ions. Compound 2 shows a three-dimensional (3D) structure constructed from 2D layer motifs joined by μ2-HMIDC2− or μ3-MIDC3− ligands. The thermal and solid-state photoluminescence properties of complexes 1–4 have been determined as well.