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

Abstract

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

The surface barrier phenomenon at the loading of metal-organic frameworks

“…M etal-organic frameworks (MOFs) 1 are an important class of nanoporous crystalline materials with several exclusive properties: large surface areas 2 , high diversity 3,4 and the ability to alter these properties over wide ranges in a rational manner 5,6 . MOFs already have many interesting applications, such as storing hydrogen 7 or greenhouse 8 gases and for gas separation 9 .…”

Crystal structure of catena-poly[(μ3-5-(4-(tetrazol-1-id-5-yl)phenoxy)benzene-1,3-dicarboxyato-κ3 O:O′:N)(4-(3-(pyridin-4-yl)propyl)pyridinium-κN)zinc(II)], C28H22ZnN6O5

“…The coordination chemistry of pyridinecarboxylic, pyrazolecarboxylic, imidazolecarboxylic and tetrazolecarboxylic acids based heterocyclic acids has been extensively studied and is mostly related to their good coordination ability and diverse coordination modes [1][2][3][4]. In this study, we report the structure of a new zinc(II) complex with the mixture of 1,3-bis(4-pyridyl)propane (bpp) and 5-(4′-(tetrazol-5′′-yl)phenoxy) isophthalic acid (TPI …”

Gözenekli malzemelerde Pr(III) iyonlarının anten etkisi ile duyarlılaştırılması

“…Generally, aromatic polycarboxylates are favoured to other organic ligands because they generate robust three dimensional (3D) frameworks with interesting porous properties and large aperture loops [3]. Furthermore, polycarboxylate anions are suitable bridging ligands for constructing porous metal organic frameworks which can find lots of potential application areas (Scheme 1) [4][5][6][7]. Also, lanthanide cations have larger ionic radius and higher coordination numbers than transition metals and they can be coordinated with numerous organic ligands that lead to different topologies [8].…”