Three novel topologically different metal–organic frameworks built from 3-nitro-4-(pyridin-4-yl)benzoic acid

Abstract

The design and synthesis of metal–organic frameworks (MOFs) have attracted much interest due to the intriguing diversity of their architectures and topologies. However, building MOFs with different topological structures from the same ligand is still a challenge. Using 3‐nitro‐4‐(pyridin‐4‐yl)benzoic acid (HL) as a new ligand, three novel MOFs, namely poly[[(N,N‐dimethylformamide‐κO)bis[μ2‐3‐nitro‐4‐(pyridin‐4‐yl)benzoato‐κ3O,O′:N]cadmium(II)] N,N‐dimethylformamide monosolvate methanol monosolvate], {[Cd(C12H7N2O4)2(C3H7NO)]·C3H7NO·CH3OH}n, (1), poly[[(μ2‐acetato‐κ2O:O′)[μ3‐3‐nitro‐4‐(pyridin‐4‐yl)benzoato‐κ3O:O′:N]bis[μ3‐3‐nitro‐4‐(pyridin‐4‐yl)benzoato‐κ4O,O′:O′:N]dicadmium(II)] N,N‐dimethylacetamide disolvate monohydrate], {[Cd2(C12H7N2O4)3(CH3CO2)]·2C4H9NO·H2O}n, (2), and catena‐poly[[[diaquanickel(II)]‐bis[μ2‐3‐nitro‐4‐(pyridin‐4‐yl)benzoato‐κ2O:N]] N,N‐dimethylacetamide disolvate], {[Ni(C12H7N2O4)2(H2O)2]·2C4H9NO}n, (3), have been prepared. Single‐crystal structure analysis shows that the CdII atom in MOF (1) has a distorted pentagonal bipyramidal [CdN2O5] coordination geometry. The [CdN2O5] units as 4‐connected nodes are interconnected by L− ligands to form a fourfold interpenetrating three‐dimensional (3D) framework with a dia topology. In MOF (2), there are two crystallographically different CdII ions showing a distorted pentagonal bipyramidal [CdNO6] and a distorted octahedral [CdN2O4] coordination geometry, respectively. Two CdII ions are connected by three carboxylate groups to form a binuclear [Cd2(COO)3] cluster. Each binuclear cluster as a 6‐connected node is further linked by acetate groups and L− ligands to produce a non‐interpenetrating 3D framework with a pcu topology. MOF (3) contains two crystallographically distinct NiII ions on special positions. Each NiII ion adopts an elongated octahedral [NiN2O4] geometry. Each NiII ion as a 4‐connected node is linked by L− ligands to generate a two‐dimensional network with an sql topology, which is further stabilized by two types of intermolecular OW—HW…O hydrogen bonds to form a 3D supramolecular framework. MOFs (1)–(3) were also characterized by powder X‐ray diffraction, IR spectroscopy and thermogravimetic analysis. Furthermore, the solid‐state photoluminescence of HL and MOFs (1) and (2) have been investigated. The photoluminescence of MOFs (1) and (2) are enhanced and red‐shifted with respect to free HL. The gas adsorption investigation of MOF (2) indicates a good separation selectivity (71) of CO2/N2 at 273 K (i.e. the amount of CO2 adsorption is 71 times higher than N2 at the same pressure).

Synthesis and Characterization of a Novel Zinc-Based Metal-Organic Framework Containing Benzoic Acid: A Low-Toxicity Carrier for Drug Delivery

“…For example, Qin et al synthesized a Ni-based MOF using 3-nitro-4-(pyridine-4-yl) benzoic acid as ligands. Meanwhile, the MOFs started decomposing beyond 364°C, showing remarkably high structural stability due to their 3D supramolecular frameworks ( 21 ). Jin et al investigated an uncommon 3D MOF based on benzoic acid, which possessed excellent stability and diverse function compared with MOFs formed by pyridine (ligand) with N as the coordination atom ( 22 ).…”

Cube-Related Corner Coalesced Nets

“…Out of the natural or synthesized materials like diamond, diamond-like carbon, metal oxides, etc., used for their high density/hardness or other physico-chemical properties, zeolites [2] and metal-organic frameworks (MOFs) [3,4,5] are appreciated for their light structures, with voids inside that can be occupied by appropriate guests, or remain empty. In this article, such light structures are termed “spongy” ones.…”