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

Four polymeric frameworks, {[Cd(HMIDC)(phen)]center dot H2O}(n) (1), {[Cd-4(HMIDC)(4)]center dot 8H(2)O}(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 mu(2)-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 mu(2)-HMIDC2 or mu(3)-MIDC3 ligands. The thermal and solid-state photoluminescence properties of complexes 1-4 have been determined as well. (C) 2011 Elsevier B.V. All rights reserved.