Zeolite-like Metal-organic Framework Research Articles

Biomineralization of Human Genomic DNA into ZIF-8, a Zeolite-Like Metal-Organic Framework.

We studied human genomic DNA isolated from lymphocytes of peripheral blood of healthy volunteers using Proba-NK kit (DNA-Technology LLC, Russia). Genomic DNA purity and concentration was estimated spectrophotometrically at 260/280 nm using Tecan Infinity 200 Pro plate reader (Tecan Instruments, Austria). ZIF-8 was synthesized in the physiological conditions (37°C) by mixing zinc salt and 2-methylimidazole aqueous solutions at different molar ratios. Human genomic DNA was encapsulated into ZIF-8 in similar conditions. The obtained MOF and DNA@ZIF-8 composite were studied using X-ray powder diffraction at the Phaser D2 XRPD device (Bruker, USA), and the specific surface area was estimated using Autosorb iQ porosimetry analyzer (Quantachrome, USA). The encapsulated DNA was quantified by dissolving DNA@ZIF-8 composite in the citrate buffer. DNA integrity was assessed by real-time allele-specific PCR (AS-PCR) using the kits for single nucleotide polymorphisms (Lytech, Russia) at the Quantstudio 6 Pro PCR machine (Thermo Scientific, USA). In case of using the kits with electrophoretic detection, the amplification was performed on the thermal cycler T100 (Thermo Scientific, USA). The polymer ZIF-8 and DNA@ZIF-8 composite were obtained at different molar ratios of zinc ions and 2-methylimidazole. We characterized their structure and specific surface area. Genomic DNA biomineralization efficacy was found to be about 7-8%. PCR indicated the integrity of non-selectively chosen loci within the biomineralized DNA. The study confirmed the possibility of human genomic DNA encapsulation into ZIF-8 metal-organic framework. After the biomineralization, DNA was found to preserve feasibility to be used in studies to investigate genetic constructs.

Polynuclear Rare-Earth Cluster-Directed Self-Assembly of Highly Porous Zeolite-like Metal-Organic Frameworks with Methane Storage Property.

Due to their intrinsic structural features, the design and synthesis of a new type of zeolite-like metal-organic frameworks (ZMOFs) is highly desirable but challenging. Herein, solvothermal reactions between an angular dicarboxylate linker and rare-earth (RE) ions afforded two RE-MOFs, namely, Tb-ZMOF-2 and Tb-ZMOF-3, respectively. Structural analyses reveal that Tb-ZMOF-2 encompasses a novel [446482] cage, while Tb-ZMOF-3 contains nonanuclear (i.e., D6R) and hexanuclear (i.e., D4R) RE clusters simultaneously, subsequently resulting in two new zeolitic topologies. Thanks to its high surface area and pore volume, Tb-ZMOF-2 demonstrates considerably high gravimetric and volumetric methane storage working capacities.

Face-directed assembly of tailored isoreticular MOFs using centring structure-directing agents

Building blocks with low connectivity and no embedded directionality are prone to polymorphism, as demonstrated by the diversity of 4-connected zeolitic nets (>250). As a result, their deployment for design in reticular and isoreticular chemistries remains a challenge. However, the ability to control geometrical peculiarities offers potential to deviate from the assembly of default structures. Here we report the face-directed assembly of >20 isoreticular zeolite-like metal–organic frameworks (ZMOFs) by using polytopic expanding and tightening centring structure-directing agents (cSDAs). The cSDAs are selected with the appropriate geometrical coding information to alter and control the orientation of adjacent supermolecular building blocks. The ZMOFs have an underlying sodalite (sod) topology that is remarkably suited for the rational assembly of multinary materials. In addition to a variety of metal cations (In, Fe, Co and Ni), a diverse range of cSDAs (di-, tri-, tetra-, hexa-, pyridyl or imidazole) are used and combined. Our approach enables isoreticular possibilities at both extremities of the porous materials spectrum: In-sod-ZMOF-102 exhibits small pore aperture suitable for efficient separation, while Fe-sod-ZMOF-320 with 48-Å-wide mesopores exhibits high hydrogen uptake, methane storage working capacity and a high gravimetric working capacity for oxygen.

A promising sensing platform for explosive markers: Zeolite-like metal-organic framework based monolithic composite as a case study

Preconcentration for on-site detection or subsequent determination is a promising technique for selective sensing explosive markers at low concentrations. Here, we report divinylbenzene monolithic polymer in its blank form (neat-DVB) and as a composite incorporated with sodalite topology zeolite-like metal-organic frameworks (3-ZMOF@DVB), as a sensitive, selective, and cost-effective porous preconcentrator for aliphatic nitroalkanes in the vapor phase as explosive markers at infinite dilution. The developed materials were fabricated as 18 cm gas chromatography (GC) monolithic capillary columns to study their separation performance of nitroalkane mixture and the subsequent physicochemical study of adsorption using the inverse gas chromatography (IGC) technique. A strong preconcentration effect was indicated by a specific retention volume adsorption/desorption ratio equal to 3 for nitromethane on the neat-DVB monolith host-guest interaction, and a 14% higher ratio was observed using the 3-ZMOF@DVB monolithic composite despite the low percentage of 0.7 wt.% of sod-ZMOF added. Furthermore, Incorporating ZMOF resulted in a higher percentage of micropores, increasing the degree of freedom more than bringing stronger adsorption and entropic-driven interaction more than enthalpic. The specific free energy of adsorption (ΔGS) values increased for polar probes and nitroalkanes, denoting that adding ZMOFs earned the DVB monolithic matrix a more specific character. Afterward, Lewis acid-base properties were calculated, estimating the electron acceptor (KA) and electron donor (KB) constants. The neat-DVB was found to have a Lewis basic character with KB/KA = 7.71, and the 3-ZMOF@DVB had a less Lewis basic character with KB/KA = 3.82. An increased electron-accepting nature can be directly related to incorporating sod-ZMOF into the DVB monolithic matrix. This work considers the initial step in presenting a portable explosives detector or preconcentrating explosive markers trace prior to more sophisticated analysis. Additionally, the IGC technique allows for understanding the factors that led to the superior adsorption of nitroalkanes for the developed materials.

Edge-rich Co/N-doped 3D nanosheet stacked carbon as an efficient dual-function electrocatalyst for rechargeable Zn-air battery

The development of high-efficiency oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) dual-function electrocatalysts based on transition metal and nitrogen co-doped carbon material is vital to the development of rechargeable Zn-air battery. In this work, dual-function oxygen electrocatalysts of 2D graphene-like (NC) and 3D nanosheet stacked carbon (CNC) derived from Zn-based zeolite-like metalorganic frameworks were prepared from the complex of imidazole-4, 5-dicarboxylic acid (4,5-Imdc) with only zinc nitrate (4,5-Imdc-Zn) or zinc and cobalt nitrate (4,5-Imdc-ZnCo). Morphology and catalytic activity of NC and CNC were studied in detail. After high temperature calcination, 4,5-Imdc-Zn developed into a 2D graphene-like structure (NC). While derivative of 4,5-Imdc-ZnCo appears a 3D nanosheet stacked (CNC) structure induced by a “pinning effect” of the existing Co ions. With increased defects, edges and Co-Nx active sites compared to NC, CNC shows more excellent electrocatalytic activity.

Feasible ethylene separation from a ternary mixture using zeolite-like metal-organic framework@divinylbenzene composite monolith

Ethylene is a vital intermediate in the petrochemical industry, and its purification from a C2 ternary mixture of up to 99.9% is essential to obtain a polymer-grade gas in an energy-demanding process. Adsorption-based separation offers an alternative approach for ethylene purification in a one-step process. Here, we report the fabrication of a monolithic composite from a zeolite-like metal-organic framework with a sodalite topology (sod-ZMOF) incorporated into a divinylbenzene polymer (ZMOF@DVB), to purify ethylene from binary and ternary mixtures of C2 hydrocarbons. The monolithic structure provides the composite with mechanical stability and high permeability, while only 2.31 wt% loading of sod-ZMOF nanoparticles has increased the BET surface area by 2.5 times, focused the pore size at 10.1 Å, and allowed for specific interactions. Gas chromatography was used to investigate the separation performance of the composite, reviling a quite satisfying selectivity of ethane/ethylene (1.89) and acetylene/ethylene (1.28), with comparable values to those of benchmark adsorbents used for similar applications and calculated via the ideal adsorbed solution theory (IAST). It is proposed that the anionic framework boosted the high polarizable ethane molecules' adsorption over ethylene; on the other hand, the Lewis basic nature of the extra-framework imidazolium cations neutralizes the anionic ZMOF structure drives acetylene's preferential adsorption over ethylene. As a proof of concept, imidazolium cations were exchanged in-situ by Na+ cations, and selectivities decreased to 1.37 for ethane/ethylene and 1.15 for acetylene/ethylene. An inverse gas chromatography approach was utilized to evaluate the thermodynamic parameters and showed an enthalpic-entropic motivated separation before cation exchange. However, after removing bulky imidazolium cations, separation became more entropic-driven.

A monolithic composite based on zeolite-like metal-organic framework@divinylbenzene polymer separates azeotropic fluorocarbon mixture efficiently

Organic monolithic columns are mainly used to separate macromolecules; however, many attempts to extend their performance toward small molecules were examined by incorporating micro- and nanoparticles. The incorporation technique enabled utilizing organic monoliths in gas chromatography (GC) for small molecules, which are still scarce. Here, we prepared a composite matrix of capillary monolithic columns of a zeolite-like metal-organic framework with a sodalite topology (sod-ZMOF) and Divinylbenzene polymer (DVB) for GC separations under 0.5 MPa. Relatively short DVB monolithic columns (18 cm long × 0.25 mm i.d.) incorporated with a tiny amount of sod-ZMOF nanoparticles (0.7 and 1.17 wt%) with an average particle size of 225 nm were successfully fabricated and used to separate linear alkanes and polar probes mixtures with increasing resolution up to 3.7 and 5.1 times, respectively, compared to a blank DVB monolithic column. A high-performance separation of linear alkanes series mixture (methane to decane) was exhibited in less than 2 min. McReynolds constants revealed that sod-ZMOF provided the composite monolith with a nonpolar character yielding a negative average polarity value smaller than the standard squalene column. An Excellent retention time of pentane and octane day-to-day reproducibility was achieved during 16 days and over more than 500 runs with RSD% of 2.25% and 3.3% using a composite monolithic column with 5 mg mL−1 sod-ZMOF (5-ZMOF@DVB). In addition, a qualitative determination of the gas mixture content of three commercially available Lighter gas cartridges was performed via the 5-ZMOF@DVB column. Finally, successfully separating an azeotropic freon mixture of difluoromethane (R-32) and pentafluoroethane (R-125) was achieved with a selectivity of up to 4.84. A further thermodynamic study related the preferential adsorption of R-125 to entropic factors rather than enthalpic while trapping inside ZMOF pores. This work sheds light on utilizing the infinite diversity of MOFs and combining their properties with high permeability and easily fabricated organic monoliths for GC separations of light molecules and gasses. Furthermore, the study highlights the role of GC as an easy and fast approach for the preliminary evaluation of the separation efficiency of porous polymers.

A Zeolite-Like Metal-Organic Framework Based Membrane for Reverse Selective Hydrogen Separation and Butane Isomer Sieving.

Here, the fabrication of a defect-free membrane that is based on a zeolite-like metal-organic framework (ZMOF) with the underlying ana topology is reported. The unique ana-ZMOF structure provides high degree of pore connectivity, which is reflected by the fast transport of gases. Prominently, it offers an optimum pore-aperture size, affording notable sieving selectivity for butane/isobutane, and optimal pore energetics for reverse CO2 /H2 separation. This emphasize the potential for the application of pure MOF membranes, paving the way to more sustainability of energy resources.

A Zeolite‐Like Metal–Organic Framework Based Membrane for Reverse Selective Hydrogen Separation and Butane Isomer Sieving

AbstractHere, the fabrication of a defect‐free membrane that is based on a zeolite‐like metal‐organic framework (ZMOF) with the underlying ana topology is reported. The unique ana‐ZMOF structure provides high degree of pore connectivity, which is reflected by the fast transport of gases. Prominently, it offers an optimum pore‐aperture size, affording notable sieving selectivity for butane/isobutane, and optimal pore energetics for reverse CO2/H2 separation. This emphasize the potential for the application of pure MOF membranes, paving the way to more sustainability of energy resources.

Hydrophobic ZIF-8 covered active carbon for CO2 capture from humid gas

The performance of activated carbon (AC) will be severely affected for carbon dioxide (CO2) capture in flue gas, as they usually suffer from competitive adsorption of water vapor. Establishment of a barrier against moisture on the surface of porous adsorbent material could potentially address this issue. Zeolite-like metal–organic frameworks (ZIF-8) as a promising adsorbent material demonstrates hydrophobic properties, large specific surface area, and highly porous structure. Here, by further growth of ZIF-8 on polydopamine (PDA)-coated bio-based carbon (AC@PDA), we fabricate hydrophobic final product (AC@ZIF-8). The CO2 capture capacities of AC@ZIF-8 was 41.69 cm3/g, which is only 13.61% lower than that of the initial AC under dry conditions. The hydrophobic ZIF-8 layer can effectively prevent water molecules from reaching the interior AC. Therefore, the adsorption of CO2 for AC@ZIF-8 decreased by only 16.74% under high relative humidity, while it decreased by 61.27% for bare AC. This strategy will broaden the applications of carbon-based adsorbents for CO2 capture under severely humid conditions. We believe that this approach is also applicable for an extensive set of CO2 capture materials that suffer from water instability.

Encapsulation of cobaltocenium ions in a zeolite-like metal–organic framework

Preparation of highly stable “ship-in-a-bottle” typle zeolite-like metal-organic framework (ZMOF) using cobaltocenium ions as a template.

Zeolite AST: Relativistic degree and distance based topological descriptors

Zeolite AST framework is one of the most versatile cage frameworks due to its functional and structural simplicity, consisting of two four- and six-membered rings with tunable pore sizes. The AST framework provides an excellent model for the systematic study of the possible substitution of atoms at the centre of the primary building unit of the framework. It has recently been demonstrated to be one of the most attractive structures for deriving metal organic frameworks and zeolite-like metal organic frameworks, with adjustable large and extra-large cavities. This specific property has given tremendous thrust to the synthesis, characterization, and modification of new novel frameworks with an AST structure that are proving to be very effective materials in the fields of optics, heterogeneous catalysis, and hydrogen storage. In our study, we employ relativistic topological models that facilitate computations of exact mathematical expressions for the degree and distance based structural descriptors by using an orthogonal approach to partition the bonds of the rectangular AST framework. Such expressions would find novel applications in QSAR and QSPR models for large AST zeolites, especially in the derivations of thermodynamic, spectroscopic and topological properties of these materials.

Reticular chemistry for the rational design of mechanically robust mesoporous merged-net metal-organic frameworks

Reticular chemistry for the rational design of mechanically robust mesoporous merged-net metal-organic frameworks

Sensitive and Stable Electrochemical Sensor for Folic Acid Determination Using a ZIF-67/AgNWs Nanocomposite

An electrochemical sensor using silver nanowires (AgNWs)-doped with a zeolite-like metal–organic framework (ZIF-67) was developed for highly sensitive and stable determination of folic acid (FA). The ZIF-67/AgNWs nanocomposite was prepared by a one-step reaction via a template method and drop-coated onto the surface of a screen-printed carbon electrode (SPCE) to form a ZIF-67/AgNWs@SPCE electrochemical sensing platform. The electrochemical square wave voltammetry (SWV) curve for this sensing platform was measured in an electrolyte solution containing FA under the optimum experimental conditions. The redox peak current of FA (IFA) increased with increases in the FA concentration (CFA). There was a linear relationship between IFA and CFA in the range of 0.1 μM to 10 μM, and the determination limit was 30 nM. The ZIF-67/AgNWs@SPCE was used as an electrochemical sensor for FA which maintained a good stability over 7 days and showed good determination performance in real samples with a high recovery rate (100.9–102.1%, n = 6).

Synthesis, structure and high methane storage of pure D6R Yb(Y) nonanuclear cluster-based zeolite-like metal–organic frameworks

Pure RE nonanuclear cluster-based ZMOFs with a topology of gme have been constructed using an angular linker and RE ions. Both RE(Yb/Y)-ZMOFs demonstrate relatively high surface areas, pore volumes and gravimetric methane storage working capacities.

Hydroamination of Phenylacetylene with Aniline over Gold Nanoparticles Embedded in the Boron Imidazolate Framework BIF-66 and Zeolitic Imidazolate Framework ZIF-67.

The hydroamination of alkynes is an atom-economy process in the organic synthesis for the C-N bond formation, thereby allowing the production of fine chemicals and intermediates. However, direct interaction between alkynes and amines is complicated due to the electron enrichment of both compounds. Therefore, efficient hydroamination catalysts, especially heterogeneous ones, are in great demand. This work aimed at the development of novel heterogeneous catalysts based on zeolite-like metal-organic frameworks for phenylacetylene hydroamination. The sodalite (SOD) type zeolitic imidazolate framework ZIF-67 (Co(meim)2, meim = 2-methylimidazolate) and boron imidazolate framework BIF-66 ({Co[B(im)4]2}n, im = imidazolate) were studied as the carriers for the gold nanoparticles (Au-NPs). Au-NPs were embedded in the ZIF-67 and BIF-66 matrices by incipient wetness impregnation. Au@ZIF-67 and Au@BIF-66 hybrids were studied for the first time in the liquid phase hydroamination of phenylacetylene with aniline in an air atmosphere and have shown high activity and selectivity in respect to imine in this process. The pronounced impact of the nature of the metal-organic carrier, Au source, and reducing agent on the catalytic performance of the synthesized nanomaterials was found. To the best of our knowledge, it is the first example of using the zeolitic imidazolate framework and boron-imidazolate framework as the components of the gold-containing catalytic systems for the alkyne hydroamination.

Nano-sized zeolite-like metal-organic frameworks induced hematological effects on red blood cell

Understanding the toxicity of metal-organic frameworks (MOFs) is important for improving their biocompatibility in further applications, especially the hematotoxicity of MOFs due to the unavoidable contact of MOFs with blood in biomedical science. Here we report the hematotoxicity and underlying mechanisms of nano-sized zeolite-like MOFs ZIF-8 and ZIF-67 because of their wide applications in biomedical science. ZIF-67 induced significant hemolysis of red blood cell (Rb) through breaking the structure of membrane due to the generation of free radicals, whereas ZIF-8 was hematocompatible. ZIF-67 was thus internalized by Rb and then bound with hemoglobin via hydrogen bond and van der Waals force, which influenced the structure and function of hemoglobin in accompany with heme release. These findings reveal the detailed mechanism of the hematological effects of MOFs on Rb and are helpful to the assessment of the toxicity and potential health risks of MOFs and the design of biosafe MOFs for biomedical applications.

Metal-free N and O Co-doped carbon directly derived from bicrystal Zn-based zeolite-like metal-organic frameworks as durable high-performance pH-universal oxygen reduction reaction catalyst

A simple and green approach is studied for the preparation of a high-activity metal-free N,O-codoped porous carbon (NOPC) electrocatalyst by one-step pyrolysis of pristine zinc-based zeolite-like metal-organic framework (Zn-ZMOF) synthesized by hydrothermal method from Zn2+ and 4,5-imidazoledicarboxylic acid (H3IDC) in H2O solvent. It is found that the structure and electroactivity of Zn-ZMOF and NOPC vary with the molar ratio of H3IDC to zinc acetate. NOPC shows pH-universal electrocatalytic property for oxygen reduction reaction and its electrocatalytic performance is similar to that of Pt/C in alkaline and neutral electrolytes, and is close to that of Pt/C in acidic electrolyte, which is a relatively rare case for metal-free porous carbon derived from pristine MOF. Meanwhile, NOPC displays higher long-term stability and better tolerance to methanol and carbon monoxide poisoning than that of commercial Pt/C. The excellent performance of NOPC is mainly due to the special structure of the precursor Zn-ZMOF, and the synergism of abundant active sites, micro/mesoporous structure, large specific surface area, and high degree of graphitization.

The Importance of Highly Connected Building Units in Reticular Chemistry: Thoughtful Design of Metal-Organic Frameworks.

The prediction of crystal structures assembled in three dimensions has been considered for a long time, simultaneously as a chemical wasteland and a certain growth point of the chemistry of the future. Less than 30 years after Roald Hoffmann's statement, we can categorically affirm that the elevation of reticular chemistry and the introduction of metal-organic frameworks (MOFs) significantly tackled this tridimensional assembly issue. MOFs result from the assembly of organic polytopic organic ligands bridging metal nodes, clusters, chains, or layers together into mostly three-periodic open frameworks. They can exhibit extremely high porosity and offer great potential as revolutionary catalysts, drug carrier systems, sensors, smart materials, and, of course, separation agents. Overall, the progressive development of reticular chemistry has been a game changer in materials chemistry during the last 25 years.Such diverse properties often result not only from the selected organic and inorganic molecular building blocks (MBBs) but also from their distribution within the framework. Indeed, the size and shape of the porous system, as well as the location of active sites influence the overall properties. Therefore, in the continuity of achieving the crystallization of three-periodic structures, chemists and crystal engineers faced the next challenge, as summarized by John Maddox: "it remains in general impossible to predict the structure of even the simplest crystallographic solids from knowledge of their chemical composition". This is where rational design takes place.In this Account, we detail three specific approaches developed by our group to facilitate the design and assembly of finely tuned MOFs. All are based on careful geometrical consideration and a deep study and understanding of the existing nets and topologies. We recognized that highly connected nets, if possible, edge-transitive, are ideal blueprints because their number is limited in contrast to nets with lower connectivity. Therefore, we embarked on taking advantage of existing highly connected MBBs, or, in parallel, promoting their formation to meet our requirements. This is achieved by utilizing externally decorated metal-organic polyhedra as supermolecular building blocks (SBBs), serving as a net-coding building unit, comprising the requisite connectivity and directional information coding for the chosen nets. The SBB approach allowed the synthesis of several families of SBB-based MOFs, including fcu, rht, and gea-MOFs, that are detailed here.The second strategy is directly inherited from the success of the SBB approach. In seeking highly connected building units, our group naturally expanded its research focus to nets that can be deconstructed into layers, pillared in various ways. In the supermolecular building layer (SBL) approach, the layers have an almost infinite connectivity, and the framework backbone is fixed in two dimensions while the third is free for pillar expansion and functionalization. The cases of trigonal pillaring leading to rtl, eea, and apo MOFs as well as the quadrangular pillaring leading to a family of tbo-MOFs are discussed here, along with recent cases of highly connected pillars in pek and aea-MOFs.Finally, our experience with highly coordinated MBBs led us to develop a novel way to use them as secondary building units of lower connectivity and unlock the possibility of assembling a novel class of zeolite-like MOFs (ZMOFs). The case of the Zr-sod-ZMOFs designed through a cantellation strategy is described as a future leading direction of MOF design.

Recent progress in the design and synthesis of zeolite-like metal-organic frameworks (ZMOFs).

This article highlights recent examples of the design and synthesis of zeolite-like metal-organic frameworks (ZMOFs). ZMOFs are a subset of metal-organic frameworks (MOFs) that exhibit the same topologies as traditional inorganic zeolites. These frameworks have attracted research interest because of their unique pore systems and distinctive cage-based cavities. With the adoption of a molecular building block (MBB) strategy, many ZMOFs with high stability and performance can be rationally designed and synthesized using various secondary building units (SBUs).