Three-dimensional Microporous Metal Organic Framework Research Articles

Photocatalytic and Ferric Ion Sensing Properties of a New Three-Dimensional Metal-Organic Framework Based on Cuboctahedral Secondary Building Units.

A new three-dimensional microporous metal–organic framework based on Zn(II) clusters with the formula {[Zn7(NDC)5.5(μ4-OH)3]·7DMF}n (1) (H2NDC = 1,4-naphthalenedicarboxylic acid) had been synthesized and characterized. The MOF 1 displays an uncommon bsn topology, which is based on a unique heptanuclear Zn7(OH)3(CO2)11 cluster as a secondary building unit. The MOF had been employed as a photocatalyst for the photodegradation of model organic dyes rhodamine B and methyl violet in light. The results of photocatalytic experiments showed that 1 can successfully be employed as the photocatalyst for the benign decomposition of these dyes. A mechanism for the photcatalysis exhibited by 1 had been proposed using the results of density of states (DOS) and partial DOS calculations. The fluorescence properties of the MOF have been investigated, which revealed that 1 could be exploited as the luminescent sensor to recognize Fe3+ ions with perceptible quenching (Ksv = 6.55 × 104 M–1) and a limit of detection of 1.16 ppm.

Sonochemically synthesized microporous metal–organic framework representing unique selectivity for detection of Fe3+ ions

Synthesis of metal–organic framework (MOF) materials via ultrasound (US) irradiation involves shorter reaction times and offers enhanced control of particle size and morphology compared to conventional electric heating. Here, we report the exploration of highly luminescent three-dimensional microporous metal–organic framework, [Zn2(oba)2(bpy)], (1; H2oba = 4,4′-oxybis(benzoicacid); bpy = 4,4′-bipyridine) synthesized by sonochemistry for highly selective and sensitive detection of Fe3+ in MeOH solution via a fluorescence quenching mechanism. Fluorescence titration experiments reveal that 1 is highly selective for Fe3+ ion with a response time of <2 min and the limit of detection (LOD) reaches a low level of 0.3 μM (17 ppb). The luminescence is completely quenched in 100 µM MeOH solution of Fe3+. Furthermore, the static quenching constant is calculated to be upper than 58 000 M−1 by the fluorescence titration experiment in low concentration of Fe3+. No interferences from 250 μM As3+, Cd2+, Zn2+, Co2+, Ni2+, Cu2+, Pb2+, Mn2+ and Al3+ were found for the detection of Fe3+. Importantly, 1 can be cycled at least four times without loss of emission signals, which suggests that the functionalized 1 is a promising luminescent probe for selectively sensing of Fe3+ ions.

Highly Selective Gaseous and Liquid-Phase Separation over a Novel Cobalt(II) Metal–Organic Framework

The mild recognition sites of oxygen atoms and phenyl rings from 5-(4-pyridyl)-methoxyl isophthalic acid (5,4-PMIA2-) moieties and tetrakis(4-pyridyloxymethylene) methane (TPOM) linkers inside the channels of a novel three-dimensional microporous metal-organic framework (MOF) [Co2(5,4-PMIA)2(TPOM)0.5]· xsolvent (1) are presumed to provide pore environments with moderate contacts toward guests, as indicated by grand canonical Monte Carlo simulations, which appear to be beneficial for adsorption and separation applications. As expected, 1 represents one of the rare examples that show both high storage capacity of C2H n and good adsorption selectivity of C2H n/CH4 and CO2/CH4 under ambient conditions, and yet, it has significantly lower energy consumption for regeneration. In addition, a validated submicro-1-based microsolid-phase extraction (μ-SPE) method for the determination of trace monohydroxylated polycyclic aromatic hydrocarbons in complex human urine was developed with satisfactory sensitivity and good precision by online coupling to liquid chromatography-mass spectrometry, which represents the first example of a mixed-ligand MOF applied as an efficient sorbent for μ-SPE.

Synthesis, structure and gas adsorption properties of a microporous metal–organic framework assembled from a semi-rigid tripodal carboxylic acid ligand

The design, synthesis, and structural characterization of a new cubic three-dimensional microporous metal–organic framework featuring a semi-rigid tripodal carboxylic acid ligand, 4,4′-((5-carboxy-1,3-phenylene)bis(oxy))dibenzoic acid (H3cpbda), is reported. Single-crystal X-ray diffraction analysis indicates that compound 1 possesses a novel (3,4,4)-connected network with the point symbol of {83}4{84·102}2{86}. In the framework of 1, there co-exist two types of 1D channels with different pore size (15Å and 4.5Å). The pore characteristics and gas sorption properties of this compound were investigated both at cryogenic temperatures and room temperature by experimentally measuring N2 and CO2 sorption isotherms. These studies show that compound 1 is highly porous with a pore volume of 0.98cm3/g and BET surface of 1926cm3/g. In addition, the activated 1 also shows excellent CO2 storage capacity around room temperature.

Synthesis, structure and gas adsorption properties of a stable microporous Cu-based metal–organic framework assembled from a T-shaped pyridyl dicarboxylate ligand

A three-dimensional microporous metal–organic framework assembled from a T-shaped pyridyl dicarboxylate ligand has been synthesized. It possesses high stability and adsorption capacities for CO2 (114 cm3 g−1, 273 K) under ambient pressure.

A new microporous metal–organic framework with potential for highly selective separation methane from acetylene, ethylene and ethane at room temperature

A new three-dimensional microporous metal–organic framework, Cu2(OFDI) (ZJU-61, H4OFDI=5,5′-(9-oxo-9H-fluorene-2,7-diyl)diisophthalic acid) was solvothermally synthesized. ZJU-61 features a three-dimensional structure with a rare sty-a type topology and has three different types of pore apertures. With open metal sites and suitable pore spaces, ZJU-61 can readily separate methane from gas mixture at room temperature with the highest C2H2/CH4 separation selectivity of 74.4.

A new metal–organic framework with potential for adsorptive separation of methane from carbon dioxide, acetylene, ethylene, and ethane established by simulated breakthrough experiments

A new three-dimensional microporous metal–organic framework, Cu2(MFDI) (ZJU-60, H4MFDI = 5,5′-(9,9-dimethyl-9H-fluorene-2,7-diyl)diisophthalic acid), was solvothermally synthesized. ZJU-60 features a three-dimensional structure with a rare sty-a type topology and has two different types of pore apertures. With open metal sites and suitable pore spaces, ZJU-60 can readily separate methane in nearly pure form from CO2 and C2-hydrocarbon quaternary gas mixtures at room temperature with high separation capacity and moderate selectivity. The separation feasibility has been further established by simulated breakthrough and pulse chromatographic experiments.

Three-dimensional copper (II) metal–organic framework with open metal sites and anthracene nucleus for highly selective C2H2/CH4 and C2H2/CO2 gas separation at room temperature

A new three-dimensional micro-porous metal–organic framework Cu2(ADDI) (ZJU-26; H4ADDI=5,5′-(anthracene-2,6-diyl) diisophthalic acid) with open metal sites and suitable pore space for their interactions with acetylene molecules was solvothermally synthesized and structurally characterized. ZJU-26 reveals a three-dimensional structure having hexagonal pores of about 5.0Å along the c axis and irregular pores of about 3.4×8.5Å2 along the a or b axis. Due to the introduction of anthracene ring do significantly enlarge pore size along a/b axis and enhance the interaction between MOF and acetylene, ZJU-26 indicates large adsorption enthalpies of 32.7kJ/mol for C2H2 and moderately high acetylene uptake of 84cm−1/g, highlighting ZJU-26 as the highly selective microporous metal organic framework for the C2H2/CH4 and C2H2/CO2 gas separation with separation selectivity of 45.9 and 12.5 at room temperature.

Metal–Organic Framework with Functional Amide Groups for Highly Selective Gas Separation

A new three-dimensional microporous metal–organic framework [Cu(N-(pyridin-4-yl)isonicotinamide)2(SiF6)](EtOH)2(H2O)12 (UTSA-48, UTSA = University of Texas at San Antonio) with functional −CONH– groups on the pore surfaces was synthesized and structurally characterized. The small pores and the functional −CONH– groups on the pore surfaces within the activated UTSA-48a have enabled their strong interactions with C2H2 and CO2 of adsorption enthalpy of 34.4 and 30.0 kJ mol–1, respectively. Accordingly, activated UTSA-48 exhibits highly selective gas sorption of C2H2 and CO2 over CH4 with the Henry Law’s selectivities of 53.4 and 13.2 respectively, at 296 K, thereby, highlighting the promise for its application in industrially important gas separation.

A microporous nickel–organic framework with an unusual 10-connected bct net and high capacity for CO2, H2 and hydrocarbons

Presented here is a three-dimensional microporous metal–organic framework [Ni3(μ2-H2O)2(bdc)3(pyrazine)2]·3(DMA) (1, H2bdc = terephthalic acid; DMA = N,N-dimethylacetamide) with a 10-connected bct net. The trinuclear Ni subunits act as the 10-connected nodes, and both bdc and pyrazine ligands act as the linkers. This uninodal bct net can be considered to be the combination of two subnets: one is the (4,4) layer formed by the Ni3 nodes and pyrazine linkers, and the other one is the typical pcu net built from the Ni3 nodes and bdc linkers. Remarkably, this stable microporous framework exhibits high CO2 and H2 uptake and good selectivity for CO2 over N2 at 273 K. Its sorption capacity for some hydrocarbons is also investigated.

A Microporous Metal–Organic Framework for Highly Selective Separation of Acetylene, Ethylene, and Ethane from Methane at Room Temperature

A novel three-dimensional microporous metal-organic framework Zn(4)L(DMA)(4) (UTSA-33, H(8) L=1,2,4,5-tetra(5-isophthalic acid)benzene, DMA=N,N'-dimethylacetamide) with small pores of about 4.8 to 6.5 Å was synthesized and structurally characterized as a non-interpenetrated (4,8)-connected network with the flu topology (Schläfli symbol: (4(12)6(12)8(4))(4(6))(2)). The activated UTSA-33a exhibits highly selective separation of acetylene, ethylene, and ethane from methane with the adsorption selectivities of 12 to 20 at 296 K, which has been established exclusively by the sorption isotherms and simulated breakthrough experiments, thus methane can be readily separated from their binary and even ternary mixtures at room temperature.

Three-Dimensional Pillar-Layered Copper(II) Metal−Organic Framework with Immobilized Functional OH Groups on Pore Surfaces for Highly Selective CO2/CH4 and C2H2/CH4 Gas Sorption at Room Temperature

A new three-dimensional microporous metal-organic framework Cu(BDC-OH)(4,4'-bipy)·G(x) (UTSA-15; H(2)BDC-OH = 2-hydroxy-benzenedicarboxylic acid, 4,4'-bipy =4,4'-bipyridine, G = guest molecules) with functional -OH groups on the pore surfaces was solvothermally synthesized and structurally characterized. UTSA-15 features a three-dimensional structure having 2D intercrossed channels of about 4.1 × 7.8 and 3.7 × 5.1 Å(2), respectively. The small pores and the functional -OH groups on the pore surfaces within the activated UTSA-15a have enabled their strong interactions with CO(2) and C(2)H(2) which have been revealed in their large adsorption enthalpies of 39.5 and 40.6 kJ/mol, respectively, highlighting UTSA-15a as the highly selective microporous metal-organic framework for the CO(2)/CH(4) and C(2)H(2)/CH(4) gas separation with separation selectivity of 24.2 and 55.6, respectively, at 296 K.

New Microporous Metal−Organic Framework Demonstrating Unique Selectivity for Detection of High Explosives and Aromatic Compounds

A highly luminescent three-dimensional microporous metal-organic framework, [Zn(2)(oba)(2)(bpy)]·DMA, demonstrates unique selectivity for the detection of high explosives and other aromatics via a fluorescence quenching and enhancement mechanism.

A three-dimensional microporous metal–organic framework with large hydrogen sorption hysteresis

A three-dimensional microporous metal-organic framework [Cd(2)(Tzc)(2)](n), which is dehydrated from [Cd(2)(Tzc)(2)(H(2)O)(2)](n), exhibits selective gas adsorption and large hydrogen sorption hysteresis.

A Robust Highly Interpenetrated Metal−Organic Framework Constructed from Pentanuclear Clusters for Selective Sorption of Gas Molecules

A three-dimensional microporous metal-organic framework, Zn(5)(BTA)(6)(TDA)(2)·15DMF·8H(2)O (1; HBTA = 1,2,3-benzenetriazole; H(2)TDA = thiophene-2,5-dicarboxylic acid), comprising pentanuclear [Zn(5)] cluster units, was obtained through an one-pot solvothermal reaction of Zn(NO(3))(2), 1,2,3-benzenetriazole, and thiophene-2,5-dicarboxylate. The activated 1 displays type-I N(2) gas sorption behavior with a Langmuir surface area of 607 m(2) g(-1) and exhibits interesting selective gas adsorption for C(2)H(2)/CH(4) and CO(2)/CH(4).

Three-dimensional microporous metal–organic framework constructed from Cadmium(II) ion with terephthalate and in-situ generated amino-tetrazole mixed-ligands

A new coordination polymer, [Cd 4 (atz) 6 (PTA)] n has been firstly synthesized by employing mixed-ligand of terephthalic acid (PTA) with the in-situ generated ligand of 5-amino-tetrazolate (atz − ). Compound 1 represents a 3D microporous framework constructed from Cd-tetrazolate subunits and the subunits are bridged by PTA and atz ligands. When the subunit was collided into node, compound 1 possesses an unprecedented 3, 9-connected topological network. Furthermore, the investigations of thermal stability and luminescent property of complex 1 indicate that compound 1 may be an excellent candidate for potential blue-light emitting material. A new coordination polymer, [Cd 4 (atz) 6 (PTA)] n has been firstly synthesized by employing mixed-ligand synthetic approach. Compound 1 presents a 3D microporous framework with an unprecedented 3, 9-connected topological network.

Design, structure and properties of a novel 3D metal-organic framework constructed from N-donor ligand supporting Cd(II)-carboxylate layer

A novel three-dimensional microporous metal-organic framework (MOF), Cd 3(CTC) 2(TED)(H 2O) 2 · (H 3O) 2Cl 2 ( 1) (H 3CTC = cis, cis-1,3,5-cyclohexanetricarboxylic acid and TED = triethylenediamine), has been synthesized under mild condition with mixed H 3CTC and TED ligands. It is of particular interest that twofold alternate (6,3) net subunits constructed from Cd centers and H 3CTC ligands are supported by linear TED ligands along the c axis to build a 3D architecture. This structure exhibits about 7.2 × 8.4 Å 2 channels along the [100] direction. The water adsorption isotherm shows type I behavior with approximately 0.07 mL/g pore volume. The fluorescent emission spectrum of polymer 1 shows a sharp blue-shift peak at 522 nm ( λ ex = 235 nm).

Gas sorption properties of microporous metal organic frameworks

A low-temperature gas sorption study has been carried out on four three-dimensional microporous metal organic framework (MMOF) structures and two two-dimensional layered structures. The pore characteristics are analyzed based on the argon adsorption–desorption isotherms at 87 K. The results from hydrogen sorption experiments conducted at 77 and 87 K show that all MMOFs have a relatively high hydrogen uptake, with adsorbed hydrogen densities falling in the range of liquid hydrogen. Isosteric heats of hydrogen adsorption data calculated based on the Clausius–Clapeyron equation are consistent with these observations, indicating strong sorbent–sorbate interactions.