Highly Selective Sorption of Small Hydrocarbons and Photocatalytic Properties of Three Metal–Organic Frameworks Based on Tris(4-(1H-imidazol-1-yl)phenyl)amine Ligand

High-Performance enrichment and sensitive analysis of bisphenol and its analogues in water and milk using a novel Ni-Based cationic Metal-Organic framework

A novel cationic metal-organic framework (iMOF-Ni) was designed and synthesized by a solvothermal method. It was fabricated as a solid-phase extraction (SPE) cartridge and exhibited high adsorption performance for Bisphenols (BPs). The theoretical simulation demonstrated that the adsorption mechanism between iMOF-Ni and BPs was attributed to cation-π bonding, π-π interaction, and electrostatic interactions. Under optimized SPE, a method for analyzing BPs was established by combining high-performance liquid chromatography-diode array detection (HPLC-DAD). The developed method has good linearity (R2 ≥ 0.994), low detection limits (0.07-0.16 ng/mL), and good reproducibility (1.72-6.35 %, n = 6). The applicability of the method was further evaluated by analyzing water and milk samples. Recoveries of four BPs in spiked samples were from 72.2 % to 96.6 %.

The Synthesis and Properties of TIPA-Dominated Porous Metal-Organic Frameworks

Metal-Organic Frameworks (MOFs) as a class of crystalline materials are constructed using metal nodes and organic spacers. Polydentate N-donor ligands play a mainstay-type role in the construction of metal-organic frameworks, especially cationic MOFs. Highly stable cationic MOFs with high porosity and open channels exhibit distinct advantages, they can act as a powerful ion exchange platform for the capture of toxic heavy-metal oxoanions through a Single-Crystal to Single-Crystal (SC-SC) pattern. Porous luminescent MOFs can act as nano-sized containers to encapsulate guest emitters and construct multi-emitter materials for chemical sensing. This feature article reviews the synthesis and application of porous Metal-Organic Frameworks based on tridentate ligand tris (4-(1H-imidazol-1-yl) phenyl) amine (TIPA) and focuses on design strategies for the synthesis of TIPA-dominated Metal-Organic Frameworks with high porosity and stability. The design strategies are integrated into four types: small organic molecule as auxiliaries, inorganic oxyanion as auxiliaries, small organic molecule as secondary linkers, and metal clusters as nodes. The applications of ratiometric sensing, the adsorption of oxyanions contaminants from water, and small molecule gas storage are summarized. We hope to provide experience and inspiration in the design and construction of highly porous MOFs base on polydentate N-donor ligands.

Bent-bis(triazolyl)-based coordination polymers tuned by dicarboxylate ligands: syntheses, structures and properties

Seven new coordination polymers based on the bent 1,1'-(oxybis(1,4-phenylene))-bis(1H-1,2,4-triazole) ligand, with diverse structures and novel topologies, that are directed by the dicarboxylate ligands.

Auxiliary ligand-modulated trisimidazole-based coordination polymers: syntheses, structures and photoluminescence properties

Five coordination polymers having 1,3,5-tris(1-imidazolyl)benzene and the varied O-donor auxiliary ligands were designed and synthesized. Further, the auxiliary ligands modulated these complexes with structural diversities and novel topologies.

Two new cadmium(II) coordination polymers based on imidazole-containing ligands: synthesis, structural characterization and fluorescence properties

The judicious selection of suitable ligands is vitally important in the construction of novel metal-organic frameworks (MOFs) with fascinating structures and interesting properties. Recently, imidazole-containing multidentate ligands have received much attention. Two new Cd^II coordination frameworks, namely, poly[tris{μ-1,4-bis[(1H-imidazol-1-yl)methyl]benzene-κ²N³:N^3'}tetrakis(nitrato-κ²O,O')dicadmium], [Cd₂(NO₃)₄(C₁₄H₁₄N₄)₃]_n, (I), and poly[[bis{μ₃-1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene-κ³N³:N^3':N^3''}cadmium] hexafluorosilicate], {[Cd(C₁₈H₁₈N₆)₂](SiF₆)}_n, (II), have been synthesized and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. In polymer (I), the 1,4-bis[(1H-imidazol-1-yl)methyl]benzene ligand bridges Cd²⁺ ions with a distorted seven-coordinated pentagonal bipyramidal geometry, forming a one-dimensional ladder chain, and the nitrate anions coordinate to the Cd²⁺ ions in a terminal bidentate fashion. In the crystal, adjacent chains are further connected by C-H...O hydrogen bonds to generate a two-dimensional (2D) supramolecular structure. Polymer (II) exhibits a 2D layered structure in which 1,3,5-tris[(1H-imidazol-1-yl)methyl] benzene ligands join Cd²⁺ centres having a six-coordinated octahedral structure. The layers are connected by hexafluorosilicate anions via C-H...F hydrogen-bond interactions, giving rise to a three-dimensional supramolecular network structure in the solid state. In addition, powder X-ray diffraction (PXRD) patterns were recorded, thermogravimetric analyses (TGA) carried out and fluorescence properties investigated.

Three New Metal Complexes with Imidazole-Containing Tripodal Ligands as Fluorophores for Nitroaromatics- and Ion-Selective Sensing

Three new metal-organic complexes [Cd(TIPA)(suc)0.5(NO3)·1/2H2O]n (1), [Ni(TIPA)(tda)0.5(H2O)·1/4H2O]n (2) and [Cd(TIPA)(tda)0.5·11/2H2O] (3) were synthesized via rigid tripodal ligand tris(4-(1H-imidazol-1-yl)phenyl)amine (TIPA) and three dicarboxylic acids; either succinic acid (H2suc) or 2,5-thiophenedicarboxylic acid (H2tda). Crystallographic data for 1 - 3 reveal three-dimensional (3D) networks and channels in the structures. The structure of 2 is unique featuring an interpenetrating 2D network, 2D + 2D → 3D, with the two associated 2D networks existing in two opposite spiral channels. TGA plots exhibit a loss of mass corresponding to the loss of the solvated water molecules in the 100 - 200 °C temperature region and begin to lose additional fragments only at T > 300 °C revealing the robust nature of the 3D framework in the complexes. The metal-organic frameworks (MOFs) are screened for their potential application in the detection and removal of environmentally hazardous industrial pollutants. Fluorescence emission spectra for 1 and 2 show that the two MOFs are capable of sensing nitrobenzene (NB), with the nickel complex 2 exhibiting significantly higher sensing ability. Powder XRD data measured for 1 and 2 and those of NB-treated 1 and 2 show significant differences in their patterns, providing further support for the strong interaction between the MOF complexes and NB. The fluorescence emission observed for 1 is more effectively quenched by the presence of Fe3+ than the series of 17 other metal ions investigated. Complex 3 possesses some ability to adsorb inorganic pollutants.

Crystal structure of poly[aqua-(μ2-5-methoxyisophthalate-κ3 O,O′:O′′)-(μ2-1,4-bis((1H-1,2,4-triazol-1-yl)methyl)benzene-κ2 N:N′)nickel(II), NiC21H20N6O6

C21H20NiN6O6, triclinic, P1̄ (no. 2), a = 10.1526(16) Å, b = 11.0670(18) Å, c = 11.1729(18) Å, α = 71.559(2)°, β = 69.827(2)°, γ = 70.439(2)°, V = 1081.3(3) Å3, Z = 2, R gt(F) = 0.0370, wR ref(F 2) = 0.0911, T = 296(2) K.

Dual-Emission SG7@MOF Sensor via SC-SC Transformation: Enhancing the Formation of Excimer Emission and the Range and Sensitivity of Detection

In this study, a water stable metal-organic framework FIR-53 is applied as a single-crystal container for anion exchange. The exceptional chemical stability and low crystallographic symmetry of FIR-53 makes it possible to determine anionic guests. Through ion exchange and single-crystal to single-crystal (SC-SC) transformation, 8-hydroxypyrene-1,3,6-trisulfonate (SG7, solvent green 7, ion form as SG7^3-) is introduced into the pores of FIR-53 to obtain SG7@FIR-53. Because of the spatial confinement and partition effect, SG7@FIR-53 shows the bright exciter emission of SG7 ions. Interestingly, the composite SG7@FIR-53 exhibits a sensitive fluorescence quenching response against Cr₂O₇^2- and MnO₄^- in aqueous solution. Especially, the detection limit toward MnO₄^- is as low as 0.12 ppb, which is the smallest value to date. Moreover, the prepared SG7@FIR-53 film also displays a broad response to nitro explosives in vapor/aqueous phase. Compared with the results of FIR-53, the range and sensitivity were greatly improved.

Crystal structure of poly[bis(1-methyl-[4,4′-bipyridin]-1-ium-κN)-tetrakis(μ3-sulfato-κ3 O:O′:O′′)trizinc(II)], C22H22Zn3N4O16S4

C22H22Zn3N4O16S4, monoclinic, P21/n (no. 14), a = 9.2909(2) Å, b = 16.8888(4) Å, c = 19.3547(6) Å, β = 98.924(3)°, V = 3000.22(14) Å3, Z = 4, Rgt(F) = 0.0401, wRref(F2) = 0.0942, T = 293(2) K.

Crystal structure of poly[aqua-(μ3-pyridine-3,5-dicarboxylato-κ5O,O′:O′′,O′′′,N)zinc(II)], C7H7NO6Zn

C7H7NO6Zn, monoclinic, C2/c (no. 15), a = 10.009(10) Å, b = 11.907(12) Å, c = 7.328(7) Å, β = 105.050(12)°, V = 843.3(15) Å3, Z = 2, Rgt(F) = 0.0681, wRref(F2) = 0.1757, T = 296(2) K.

Crystal structure of 4,4′-(1,4-phenylene)bis(pyridin-1-ium) catena-poly[diaqua-bis(μ2-3′,5′-dicarboxy-[1,1′-biphenyl]-2,5-dicarboxylato-κ2O:O′] dihydrate, C48H42O22N2Ca

C48H42O22N2Ca, triclinic, P1̅ (no. 2), a = 7.2548(2) Å, b = 11.7056(4) Å, c = 14.6024(4) Å, α = 72.687(3)°, β = 82.667(2)°, γ = 73.303(3)°, V = 1132.76(6) Å3, Z = 1, Rgt(F) = 0.0403, wRref(F2) = 0.0993, T = 293(2) K.

Crystal structure of 4-(4′-(pyridin-4-yl)-[1,1′-biphenyl]-4-yl)pyridin-1-ium catena-poly[{5-carboxy-4′-methyl-[1,1′-biphenyl]-3-carboxylato-κ2 O,O′}-(μ2-4′-methyl-[1,1′-biphenyl]-3,5-dicarboxylato-κ4 O,O′:O′′,O′′′)lead(II)], C52H40N2O9Pb

C52H40N2O9Pb, triclinic, P1̅ (no. 2), a = 10.3025(4) Å, b = 14.1740(9) Å, c = 16.0428(9) Å, α = 115.835(6)°, β = 97.680(4)°, γ = 90.493(4)°, V = 2083.7(2) Å3, Z = 2, R gt(F) = 0.0342, wR ref(F 2) = 0.0612, T = 293(2) K.

The influence of coordination modes and active sites of a 5-(triazol-1-yl) nicotinic ligand on the assembly of diverse MOFs

Six new complexes were successfully assembled via 5-(triazol-1-yl) nicotinic acid (HL). The L⁻ ligand shows versatile coordination modes and can form various clusters in the final structures to fine-tune the properties of MOFs.

Separation/purification of ethylene from an acetylene/ethylene mixture in a pillared-layer porous metal–organic framework

A 3D pillared-layer porous framework with narrow channels decorated with polar pore surfaces has been developed for efficient removal of C₂H₂ from a C₂H₂/C₂H₄ mixture at RT.

Crystal structure of biphenyl-2,3′,5,5′-tetracarboxylic acid – 4,4′-biphenyl-4,4′-diyldipyridine (3/2), C49H34N3O8

C49H34N3O8, triclinic, P1̅ (no. 2), a = 10.0660(3) Å, b = 14.0604(2) Å, c = 14.8204(3) Å, α = 106.697(1)°, β = 100.308(1)°, γ = 102.378(1)°, V = 1896.46(7) Å3, Z = 2, R gt (F) = 0.0541, wR ref(F 2) = 0.1258, T = 296(2) K.

Tris(bipyridine)Metal(II)-Templated Assemblies of 3D Alkali-Ruthenium Oxalate Coordination Frameworks: Crystal Structures, Characterization and Photocatalytic Activity in Water Reduction

A series of 3D oxalate-bridged ruthenium-based coordination polymers with the formula of {[Z^II(bpy)₃][M^IRu(C₂O₄)₃]}_n (Z^II = Zn²⁺ (1), Cu²⁺ (3, 4), Ru²⁺ (5, 6), Os²⁺ (7, 8); M^I = Li⁺, Na⁺; bpy = 2,2’-bipyridine) and {[Zn^II(bpy)₃](H₂O)[LiRu(C₂O₄)₃]}_n (2) has been synthesized at room temperature through a self-assembly reaction in aqueous media and characterized by single-crystal and powder X-ray diffraction, elemental analysis, infrared and diffuse reflectance UV–Vis spectroscopy and thermogravimetric analysis. The crystal structures of all compounds comprise chiral 3D honeycomb-like polymeric nets of the srs-type, which possess triangular anionic cages where [Z^II(bpy)₃]²⁺ cationic templates are selectively embedded. Structural analysis reveals that the electronic configuration of the cationic guests is affected by electrostatic interaction with the anionic framework. Moreover, the MLCT bands gaps values for 1–8 can be tuned in a rational way by judicious choice of [Z^II(bpy)₃]²⁺ guests. The 3D host-guest polymeric architectures can be used as self-supported heterogeneous photocatalysts for the reductive splitting of water, exhibiting photocatalytic activity for the evolution of H₂ under UV light irradiation.

Construction of Four Zn(II) Coordination Polymers Used as Catalysts for the Photodegradation of Organic Dyes in Water

Hydrothermal reactions of Zn(OAc)₂·2H₂O with flexible bipyridyl benzene ligand and three dicarboxylic derivatives gave rise to four new coordination polymers, [Zn₇(μ₄-O)₂(OAc)₁₀(bpmb)]_n (1), [Zn(5-OH-1,3-BDC)(bpmb)]_n (2), [Zn(1,2-BDC)(bpmb)]_n (3) and [Zn₂(ADB)₂(bpmb)]_n (4) (bpmb = 1,4-bis(pyridine-3-ylmethoxy)benzene, 5-OH-1,3-H₂BDC = 5-hydroxy-1,3-benzenedicarboxylic acid, 1,2-H₂BDC = 1,2-benzenedicarboxylic acid, H₂ADB = 2,2’-azodibenzoic acid). Their structures were characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). Compound 1 features a one-dimensional (1D) chain structure based on the rare heptanuclear [Zn₇(μ₄-O)(μ₃-OAc)₂(μ₂-OAc)₈] units. Compound 2 exhibits a novel 2D bilayer structure built from the two parallel 2D (4,4) layers. Compound 3 holds a 2D structure in which the 1,2-BDC ligands work as lockers interlocking 1D [Zn(bpmb)]_n chain. Compound 4 comprises a 3D framework constructed by 2D wrinkled [Zn₂(ADB)₄]_n networks and bpmb linkers with a six-connected pcu net. These results suggest that the motifs of the dicarboxylic ligands have significant effect on the final structures. These compounds exhibited relatively good photocatalytic activity towards the degradation of methylene blue (MB) in aqueous solution under a Xe lamp irradiation.

Four new 3D metal–organic frameworks constructed by the asymmetrical pentacarboxylate: gas sorption behaviour and magnetic properties

Four new 3D MOFs were constructed by the pentacarboxylate ligand and their structure analysis shows that 1 is based on an unprecedented Cu₁₂ hendecahedron nanocage. Also, their gas sorption behaviour and magnetic properties were investigated.

An aminopyrimidine-functionalized cage-based metal–organic framework exhibiting highly selective adsorption of C2H2 and CO2 over CH4

An aminopyrimidine-functionalized cage-based metal–organic framework has been synthesized, which exhibited exceptionally high C₂H₂ and CO₂ uptake as well as impressive adsorption selectivities towards C₂H₂ and CO₂ over CH₄.

Construction of five Zn(ii)/Cd(ii) coordination polymers derived from a new linear carboxylate/pyridyl ligand: design, synthesis, and photocatalytic properties

Reactions of Cd(OAc)₂/Zn(OAc)₂ with a new linear carboxylate/pyridyl ligand under different templates via an in situ ligand transformation reaction produced five new CPs. Complexes 1–5 exhibited relatively good photocatalytic activity towards the degradation of methylene blue.

Alkyl group-directed assembly of coordination polymers based on bis-(4-imidazol-1-yl-phenyl)-amine and their photocatalytic properties

Four new coordination polymers have been solvothermally synthesized to explore their diverse networks and photocatalytic properties.