Metal-organic frameworks constructed from imidazole dicarboxylates bearing aromatic substituents at the 2-position

Seven metal-organic frameworks, [Sr(PhHIDC)(H2O)](n) (PhH3IDC = 2-phenyl-1H-imidazole-4,5-dicarboxylic acid) (1), {[Mn(p-OHPhHIDC)(H2O)(2)]center dot H2O}(n) (p-OHPhH3IDC = 2-(p-hydroxylphenyl)-1H-imidazole-4,5-dicarboxylic acid) (2), {[Cd-2(p-OHPhHIDC)(2)(phen)(2)]center dot H2O}(n) (phen = 1,10-phenanthroline) (3), {[Cd-2(p-OHPhHIDC)(2)(2,2'-bipy)(2)]center dot H2O}(n) (2,2'-bipy = 2,2'-bipyridine) (4), [Sr(p-MePhHIDC)(H2O)](n) (p-MePhH3IDC = 2-(p-methylphenyl)-1H-imidazole-4,5-dicarboxylic acid) (5), [Cd-4(p-MePhHIDC)(4)(py)(7)(H2O)] (py = pyridine) (6) and {[Co-1.5(p-MePhIDC)(H2O)(3)]center dot H2O}(n) (7) have been synthesized under hydro(solvo)thermal conditions. X-ray single-crystal analyses reveal that they have rich structural chemistry ranging from zero-dimensional (0D) tetranuclear complex (6), one-dimensional (1D) polymers (2, 3 and 4), two-dimensional (2D) polymers (1 and 5) to three-dimensional (3D) polymer (7). In these complexes, the imidazole dicarboxylate ligands show strong coordination ability and various coordination modes, which are consistent with the theoretical prediction of the substituent (phenyl, p-hydroxylphenyl or p-methylphenyl groups) effect of PhH3IDC, p-HOPhH3IDC or p-MePhH3IDC ligands, respectively. The thermal properties and photoluminescence properties of compounds 1-7 have been investigated as well.