Three-dimensional Porous Metal-organic Framework Research Articles

A magnesium phosphonate metal-organic framework showing excellent performance for lead(II) sensing and removal from aqueous solutions.

A hydrogen-bonded three-dimensional porous metal-organic framework [Mg(H2PCD)2(H2O)2]·2H2O (denoted as Mg-MOF·2H2O; H3PCD = 9-(2-(ethoxy(hydroxy)phosphonyl)ethyl)-9H-carbazole-3,6-dicarboxylic acid) was synthesized by the reactions of H3PCD and Mg(II) under solvothermal conditions. The free carboxylate group was maintained in the pore surface by adjusting the acidic reaction conditions. The highly stable Mg-MOF exhibits excellent performance for lead(II) sensing and removal from aqueous solutions.

Synthesis, structural characterization, and carbon dioxide and hydrogen adsorption of a new three-dimensional metal organic framework Zn(BTC)4

A novel three-dimensional porous metal organic framework Zn(BTC)4 (BTC = benzene-1,3,5-tricarboxylic acid) is synthesized by the solvothermal method. This structure is characterized by single-crystal X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. This metal organic framework crystallizes in a monoclinic (P2(1)/n, V = 1795.7(2) Å3, Z = 4, Dc = 1.449 mg/cm3, α = 90.00°, β = 97.2200(10)°, γ = 90.00°, a = 9.5077(5) Å, b = 16.3950(16) Å, c = 11.6119(9) Å). The thermogravimetric analysis shows the material can be stabilized up to 350 °C, then the skeleton collapses between 350~510 °C. A luminescence test shows that the material gives out strong emission at 384 and 462 nm. The hydrogen storage capacity of this metal organic framework is 2.01 wt% at 77 K and a pressure of 10 bar. The carbon dioxide storage capacity of this metal organic framework is 4.17 mmol/g at 298 K and a pressure of 10 bar.

A sandwich electrochemiluminescent assay for determination of concanavalin A with triple signal amplification based on MoS2NF@MWCNTs modified electrode and Zn-MOF encapsulated luminol.

An ultrasensitive sandwich electrochemiluminescence (ECL) biosensor was designed for determination of concanavalin A (ConA) through the specific carbohydrate-ConA interactions. Three-dimensional porous metal-organic framework (Zn-MOF) was synthesized, which loaded a large amount of luminescent reagents as luminol by encapsulating into its pores to form Zn-MOF@luminol complex. Interestingly, Zn-MOF also acted as the coreactant accelerator in the luminol-H2O2 ECL system. This Zn-MOF@luminol complex was used as the signal probe to achieve a super strong and stable ECL signal. In addition, three-dimensional hierarchical molybdenum disulfide nanoflower and multiwalled carbon nanotubes complex (MoS2NF@MWCNTs) with peroxidase-mimicking enzyme property were used as a substrate to modify the glassy carbon electrode to further enhance the ECL signal of luminol by promoting decomposition of H2O2 into reactive oxygen species (ROSs). In addition to the horseradish peroxidase (HRP) catalysis effect on the luminol ECL signal, a triple amplified ConA sandwich ECL sensor with high sensitivity sensor was constructed. The linear range for ConA detection was from 0.5pg/mL to 100ng/mL with a detection limit of 0.3pg/mL (S/N = 3). The recovery test for ConA in human serum samples was performed with satisfactory results. Graphical abstract.

RETRACTED ARTICLE: 5-Fluorouracil Trapping in a Porous Ba(II)-organic Framework: Drug Delivery and Anti-thyroid Cancer Activity Evaluation

Solvothermal treatment of Ba(NO3)2 with the rigid tricarboxylic acid linker 4,4′,4″-s-triazine-2,4,6-triyltribenzoic acid (H3TATB) in a mixture of H2O and N,N-dimethylformamide (DMF) produces a new three-dimensional porous metal-organic framework having the chemical formula of [Ba(HTATB)-(H2O)2](DMF)4 (I). The complex I has been characterized by powder X-ray diffraction, elemental analysis and single crystal X-ray diffraction (CIF file CCDC no. 1898532). In light of its large inner spaces as well as widely distributed open metal sites, the guest-free I (Ia) has been used as a crystalline vessel for trapping the anticancer drug 5-fluorouracil (5-FU), which has been investigated both experimentally and computationally. Furthermore, MTT assay was employed to evaluate the in vitro cytotoxicity of the carrier 5-FU loaded Ia against the human thyroid cancer cell lines.

Environmentally Friendly, Co-catalyst-Free Chemical Fixation of CO2 at Mild Conditions Using Dual-Walled Nitrogen-Rich Three-Dimensional Porous Metal-Organic Frameworks.

Highly porous, polyhedral metal-organic frameworks (MOFs) of Co(II)/Ni(II), {[M6(TATAB)4(DABCO)3(H2O)3]·12DMF·9H2O} n (where M = Co(II) (1)/Ni(II) (2), H3TATAB = 4,4',4″- s-triazine-1,3,5-triyl-tri- p-aminobenzoic acid, and DABCO = 1,4-diazabicyclo[2.2.2]octane) have been synthesized solvothermally. Both MOFs 1 and 2 show a 2-fold interpenetrated 3D framework structure composed of dual-walled cages of dimension ∼ 30 Å functionalized with a high density of Lewis acidic Co(II)/Ni(II) metal sites and basic -NH- groups. Interestingly, MOF 1 shows selective adsorption of CO2 with high heat of adsorption ( Qst) value of 39.7 kJ/mol that is further supported by theoretical studies with computed binding energy (BE) of 41.17 kJ/mol. The presence of the high density of both Lewis acidic and basic sites make MOFs 1/2 ideal candidate materials to carry out co-catalyst-free cycloaddition of CO2 to epoxides. Consequently, MOFs 1/2 act as excellent recyclable catalysts for cycloaddition of CO2 to epoxides for high-yield synthesis of cyclic carbonates under co-catalyst-free mild conditions of 1 bar of CO2. Further, MOF 1 was recycled for five successive cycles without substantial loss in catalytic activity. Herein, rational design of rare examples of 3D polyhedral MOFs composed of Lewis acidic and basic sites exhibiting efficient co-catalyst-free conversion of CO2 has been demonstrated.

Theoretical investigation of selective catalytic reduction of NO on MIL-100-Fe.

MIL-100-Fe, a three-dimensional porous metal organic framework material, shows good activity for the selective catalytic reduction of NO by ammonia. Understanding reaction mechanisms at the molecular level contributes to the design and development of highly active catalysts. Herein, density functional theory calculations with the consideration of van der Waals interactions were performed to investigate the SCR mechanism on MIL-100-Fe. Lewis acid sites and Brønsted acid sites both exist on MIL-100-Fe, which are active for the SCR reaction. MIL-100-Fe exhibits the features of single-site catalysts, thus we calculated the NH3-SCR reaction process following the Eley-Rideal mechanism. The proposed NH3-SCR mechanism can be subdivided into two parts: (1) NO oxidation and (2) fast SCR reaction. Our results show that Lewis acid sites play an essential role in activating the reactants. The NO molecule is readily oxidized to NO2 species on the Fe Lewis acid sites, the adsorbed NH3 species react with gaseous NO2, and the formation of intermediate NH2NO is the rate-determining step. This study offers new and important insights into the mechanistic understanding of the NH3-SCR reaction on the MIL-100-Fe catalyst.

Control of interpenetration in a microporous metal-organic framework for significantly enhanced C2H2/CO2 separation at room temperature.

A novel non-interpenetrated three-dimensional porous metal-organic framework UTSA-68 has been controllably synthesized by altering the reaction conditions. The resulting UTSA-68a shows a notably higher porosity and adsorption selectivity (3.5-5) for C2H2/CO2 separation compared to that of doubly interpenetrated ZJU-30a (1.7-2.4) at room temperature.

Deprotonation-triggered Stokes shift fluorescence of an unexpected basic-stable metal-organic framework.

A new three-dimensional porous metal-organic framework, JUC-119, constructed by a pyrene-based dendritic organic linker, H8TIAPy (H8TIAPy = 1,3,6,8-tetrakis(3,5-isophthalic acid)pyrene), and Eu(III) has been synthesized successfully. JUC-119 shows unexpected stability under a wide range of basic conditions from 0 to 0.01 M NaOH. Furthermore, with two carboxyl groups uncoordinated in each ligand, the crystals of JUC-119 show deprotonation-triggered Stokes shift fluorescence under basic conditions. As the concentration of base increases from 0 to 0.01 M NaOH, the luminescence emission of JUC-119 becomes gradually red shifted from 455 to 485 nm. In addition, the Stokes shift shows a good linear relationship to -log[OH(-)], which makes JUC-119 promising for base sensing.

Gas Storage in a Partially Fluorinated Highly Stable Three-Dimensional Porous Metal–Organic Framework

A partially fluorinated linear rigid linker, 2,2'-bis-trifluoromethyl-biphenyl-4,4'-dicarboxylic acid (H2bfbpdc), has been synthesized. This linker forms a porous three-dimensional (3D) metal-organic framework, {[Zn4O(bfbpdc)3(bpy)0.5(H2O)]·(3DMF)(H2O)}n (1), in the presence of the colinker 4,4'-bipyridine (bpy) and Zn(NO3)2·6H2O under solvothermal condition. Single crystal X-ray analysis shows that 1 contains a 3D channel structure with highly polar pore surfaces decorated with pendant trifluoromethyl groups of bfbpdc(2-) linker. Thermogravimetric analysis (TGA) and variable temperature powder X-ray diffraction (VTPXRD) exhibit high thermal stability of the framework. The solvent molecules present in the voids can be removed by heating, maintaining the integrity of the structure to afford a porous framework. Gas (N2, H2, CH4, and CO2) and water adsorption studies were performed on this framework.

Multifunctional catalyst based on sandwich-type polyoxotungstate and MIL-101 for liquid phase oxidations

A sandwich-type polyoxometalate {(TBA)7H3[Co4(H2O)2(PW9O34)2]} was immobilized for the first time into the three-dimensional porous metal-organic framework, MIL-101. The composite material Co4(PW9)2@MIL-101 was prepared and the incorporation of the Co4(PW9)2 was confirmed using a myriad of solid state methods (FT-IR, FT-Raman, powder XRD, SEM-EDX and ICP analysis). Co4(PW9)2@MIL-101 reveals to be an active, selective and recyclable catalyst for the oxidation of different substrates: geraniol, R-(+)-limonene, styrene and cyclooctane, using H2O2 as eco-sustainable oxidant. The stability and robustness of the heterogeneous catalyst was confirmed by different techniques. The MIL-101 framework demonstrates to be a suitable and efficient support to accommodate catalytically active sandwich-type polyoxotungstates.

Structural and magnetic characterization of the tridimensional network [Fe(HCO2)3]n·nHCO2H

In this work we report the structural and magnetic characterization of a new three-dimensional porous metal–organic framework (MOF) based on iron(III) and the formate anion, [Fe(HCO2)3]n·nHCO2H (1), which was obtained by solvothermal synthesis. The tridimensional structure crystallizes in the trigonal space group Rc and is formed by highly regular octahedral Fe(OHCO)6 units. These units contain six equal Fe–O distances, with angles slightly different from 90° or 180°. The packing of 1 corresponds to a 3D covalent network defined by face sharing between the parallelepipeds, which are formed by the interactions of Fe(OHCO)6 units through formate ligands, thus generating a 41263 topology. This topology contains channels in the three spatial directions, in which it is possible to find guest molecules of formic acid. The thermogravimetric analysis shows that 1 remains stable till 180 °C; after this temperature the decomposition of 1 begins. From a magnetic point of view, the reported MOF presents an antiferromagnetic behaviour in the 296 to 20 K range. The fit of the experimental data between room temperature and 50 K, using the high temperature series model (HTS model), permits us to estimate a J value of −1.01 cm−1, which is in agreement with the reported values for analogous systems based on transition metal ions and formate ligands. Below this temperature, a weak ferromagnetism as a product of spin canting was observed due to the anti–anti coordination mode of the bridging ligand, which satisfies the requirement for Dzyaloshinsky–Moriya antisymmetric interactions between the FeIII ions. The isothermal magnetization obtained at 2 K shows that the magnetization increases linearly with the applied magnetic field, reaching a value of 0.49Nβ at the highest applied field of 50 kOe, indicating the antiferromagnetic character of the ground state. DFT calculations using a dinuclear fragment confirm the magnitude and nature of the magnetic phenomena of this extended system at high temperatures.

A three-dimensional porous metal–organic framework of unusual rob topology based on a novel fluorinated bis(imidazole) ligand

Abstract A unique 3-D open coordination framework based on a fluorinated bis(imidazole) ligand has been prepared and characterized, showing a six-connected self-penetrating network with rob (48.66.8) topology. Porosity of desolvated and resolvated samples was characterized by X-ray powder diffraction (XRPD).

New Three-Dimensional Porous Metal Organic Framework with Tetrazole Functionalized Aromatic Carboxylic Acid: Synthesis, Structure, and Gas Adsorption Properties

5-(1H-Tetrazol-1-yl)isophthalic acid (H(2)L) reacts with Cu(II) ion forming a new metal-organic framework {[CuL]·DMF·H(2)O}(∞) (1) (DMF = N,N-dimethylformamide), with a rutile-related type net topology. Compound 1 possesses a 3D structure with 1D channels that can be desolvated to yield a microporous material. Adsorption properties (N(2), H(2), O(2), CO(2), and CH(4)) of the desolvated solid [CuL] (1a) have been studied, and the results exhibit that 1a possesses fairly good capability of gas sorption for N(2), H(2), O(2), and CO(2) gases, with high selectivity ratios for O(2) over H(2) at 77 K and CO(2) over CH(4) at 195, 273, and 298 K. Furthermore, 1a has excellent O(2) uptake at 77 K and a remarkably high quantity of adsorption for CO(2) at room temperature (298 K) and atmospheric pressure, suggesting its potential applications in gas separation or purification.

A three-dimensional porous metal–organic framework with the rutile topology constructed from triangular and distorted octahedral building blocks

The solvothermal reaction of zinc acetate dihydrate with 1,3,5-benzenetricarboxylic acid yields a three-dimensional porous metal-organic framework constructed from triangular and distorted octahedral building blocks, the framework of which can be described as a decorated rutile net.