Construction of Metal-Imidazole-Based Dicarboxylate Networks with Topological Diversity: Thermal Stability, Gas Adsorption, and Fluorescent Emission Properties

• DOI: 10.1021/cg2002095
• Publication Date: 2012-03-30T17:04:50Z
• Authors: Zhi-Gang Gu; Yi-Ting Liu; Xu-Jia Hong; Qing-Guang Zhan; Zhi-Peng Zheng; Sheng-Run Zheng; Wei-Shan Li; She-Jun Hu; Yue-Peng Cai
• Keywords: Imidazole; Thermal Stability; Linker

Six new metal–organic frameworks (MOFs), namely, [Pb(H2IDC)2(H2O)]n (1), {[Pb(H2IEDC)2)]·3H2O}n (2), [Ca2(HIDC)2(H2O)]n (3), {[Ca2(IEDC)2(H2O)2]·H2O}n(4), {[Cd(HIDC)(H2O)]n (5), and {[Cd2(HIEDC)2·3H2O}n (6) (H3IDC = 4,5-imidazoledicarboxylic acid, H3IEDC 2-ethyl-1H-imidazole-4,5-dicarboxylic acid) were hydrothermally synthesized characterized. Single-crystal X-ray diffraction shows the ligand H3IDC is partially deprotonated with H2IDC– HIDC2– forms in three corresponding compounds 1, 3, 5, meanwhile also presents different deportonated motifs of H2IEDC–, IEDC3–, HIEDC2– 2, 4, 6, respectively. Moreover, these or fully ligands coordinate μ1 to μ5 manner generate one-dimensional (1D) → three-dimensional (3D) coordination polymers, displaying 10 modes. Both 1 2 have 3D supramolecular networks assembled via hydrogen bonding interactions but structure topologies. Complex a 1D chain has two-dimensional (2D) wave layer-like 44 topology. 3 MOF 310·425·510 topology built up from linear 2-connected as linker 10-connected tetranuclear metal unit [Ca4(μ2-O)6] node. However, complex 4 2D 36·46·53 Different 4-connected binuclear [Cd(O–C–O)]2 node, wave-like 5 based on created. 6 framework containing alternately arranged hydrophilic channels including (H2O)4 clusters hydrophobic occupied by ethyl groups imidazole rings, which Cd(II) ion viewed μ2-O are regarded two linkers, showing 42·84 Obviously, results reveal that existence substitute 2-position such 4,5-imidazoledicarboxylate plays critical role structural direction MOFs. Meanwhile, adsorption photoluminescent properties selected investigated.