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Metal-organic frameworks (MOFs) represent a fascinating class of solid crystalline materials which can be self-assembled in a straightforward manner by the coordination of metal ions or clusters with organic ligands. Owing to their intrinsic porous characteristics, unique chemical versatility and abundant functionalities, MOFs have received substantial attention for diverse industrial applications, including membrane separation. Exciting research activities ranging from fabrication strategies to separation applications of MOF-based membranes have appeared. Inspired by the marvelous achievements of MOF-based membranes in gas separations, liquid separations are also being explored for the purpose of constructing continuous MOFs membranes or MOF-based mixed matrix membranes. Although these are in an emerging stage of vigorous development, most efforts are directed towards improving the liquid separation efficiency with well-designed MOF-based membranes. Therefore, as an increasing trend in membrane separation, the field of MOF-based membranes for liquid separation is highlighted in this review. The criteria for judicious selection of MOFs in fabricating MOF-based membranes are given. Special attention is paid to rational design strategies for MOF-based membranes, along with the latest application progress in the area of liquid separations, such as pervaporation, water treatment, and organic solvent nanofiltration. Moreover, some attractive dual-function applications of MOF-based membranes in the removal of micropollutants, degradation, and antibacterial activity are also reviewed. Finally, we define the remaining challenges and future opportunities in this field. This Tutorial Review provides an overview and outlook for MOF-based membranes for liquid separations. Further development of MOF-based membranes for liquid separation must consider the demands of strict separation standards and environmental safety for industrial application.

Aggregation of filler particles during the formation of mixed matrix membranes is difficult to avoid when filler loadings exceed a 10–15 wt %. Such agglomeration usually leads to poor membrane performance. In this work, using a ZIF‐67 metal–organic framework (MOF) as filler along with surface modification of Ag4tz4 to improve processability and selective olefin adsorption, we demonstrate that highly loaded with a very low agglomeration degree membranes can be synthesized displaying unmatched separation selectivity (39) for C3H6/C3H8 mixtures and high permeability rates (99 Barrer), far surpassing previous reports in the literature. Through molecular dynamics simulation, the enhanced compatibility between ZIF‐67 and polymer matrix with adding Ag4tz4 was proven and the tendency in gas permeability and C3H6 selectivity in the mixed matrix membranes (MMMs) were well explained. More importantly, the membrane showed a wide range of pressure and temperature resistance, together with remarkable long‐term stability (>900 h). The modification method might help solve interface issues in MMMs and can be extended to the fabrication of other fillers to achieve high performance MMMs for gas separation. [ABSTRACT FROM AUTHOR]

The direct utilization of light to drive chemical reactions has been considered a promising approach to decarbonizing the chemical industry and storing solar energy in the form of chemical bonds. In this regard, photo‐thermal catalysis has emerged as a bright strategy due to the combination of thermal and non‐thermal contributions of sunlight. This enables the whole exploitation of the solar spectrum providing localized heating and thus an enhancement in the productivity rates. In this scenario, MOFs and MOFs‐derived materials offer great opportunities for the rational design of new photo‐thermal catalysts. In this review, we describe the different types of photo‐thermal systems, with a particular consideration on the mechanisms. Further, we describe the recent advances of MOF and MOF‐derived materials as photo‐thermal catalysts for different catalytic reactions, including organic transformations, pollutant degradation or CO2 hydrogenations. Lastly, we present our opinion on the future challenges and perspectives in the field. [ABSTRACT FROM AUTHOR]

We report the synthesis of a highly active and stable metal‐organic framework derived Ni‐based catalyst for the photothermal reduction of CO2 to CH4. Through the controlled pyrolysis of MOF‐74 (Ni), the nature of the carbonaceous species and therefore photothermal performance can be tuned. CH4 production rates of 488 mmol g−1 h−1 under UV‐visible‐IR irradiation are achieved when the catalyst is prepared under optimized conditions. No particle aggregation or significant loss of activity were observed after ten consecutive reaction cycles or more than 12 hours under continuous flow configuration. Finally, as a proof‐of‐concept, we performed an outdoor experiment under ambient solar irradiation, demonstrating the potential of our catalyst to reduce CO2 to CH4 using only solar energy. [ABSTRACT FROM AUTHOR]

We report the synthesis of a highly active and stable metal‐organic framework derived Ni‐based catalyst for the photothermal reduction of CO2 to CH4. Through the controlled pyrolysis of MOF‐74 (Ni), the nature of the carbonaceous species and therefore photothermal performance can be tuned. CH4 production rates of 488 mmol g−1 h−1 under UV‐visible‐IR irradiation are achieved when the catalyst is prepared under optimized conditions. No particle aggregation or significant loss of activity were observed after ten consecutive reaction cycles or more than 12 hours under continuous flow configuration. Finally, as a proof‐of‐concept, we performed an outdoor experiment under ambient solar irradiation, demonstrating the potential of our catalyst to reduce CO2 to CH4 using only solar energy. [ABSTRACT FROM AUTHOR]

In the realm of solids, metal–organic frameworks (MOFs) offer unique possibilities for the rational engineering of tailored physical properties. These derive from the modular, molecular make‐up of MOFs, which allows for the selection and modification of the organic and inorganic building units that construct them. The adaptable properties make MOFs interesting materials for photocatalysis, an area of increasing significance. But the molecular and porous nature of MOFs leaves the field, in some areas, juxtapositioned between semiconductor physics and homogeneous photocatalysis. While descriptors from both fields are applied in tandem, the gap between theory and experiment has widened in some areas, and arguably needs fixing. Here we review where MOFs have been shown to be similar to conventional semiconductors in photocatalysis, and where they have been shown to be more like infinite molecules in solution. We do this from the perspective of band theory, which in the context of photocatalysis, covers both the molecular and nonmolecular principles of relevance. [ABSTRACT FROM AUTHOR]

The amalgamation of different disciplines is at the heart of reticular chemistry and has broadened the boundaries of chemistry by opening up an infinite space of chemical composition, structure, and material properties. Reticular design has enabled the precise prediction of crystalline framework structures, tunability of chemical composition, incorporation of various functionalities onto the framework backbone, and as a consequence, fine‐tuning of metal–organic framework (MOF) and covalent organic framework (COF) properties beyond that of any other material class. Leveraging the unique properties of reticular materials has resulted in significant advances from both a fundamental and an applied perspective. Here, we wish to review the milestones in MOF and COF research and give a critical view on progress in their real‐world applications. Finally, we briefly discuss the major challenges in the field that need to be addressed to pave the way for industrial applications. [ABSTRACT FROM AUTHOR]

The one‐step synthesis and characterization of a new and robust titanium‐based metal–organic framework, ACM‐1, is reported. In this structure, which is based on infinite Ti−O chains and 4,4′,4′′,4′′′‐(pyrene‐1,3,6,8‐tetrayl) tetrabenzoic acid as a photosensitizer ligand, the combination of highly mobile photogenerated electrons and a strong hole localization at the organic linker results in large charge‐separation lifetimes. The suitable energies for band gap and conduction band minimum (CBM) offer great potential for a wide range of photocatalytic reactions, from hydrogen evolution to the selective oxidation of organic substrates. [ABSTRACT FROM AUTHOR]

The electrochemical reduction of CO2 holds great promise for lowering the concentration of CO2 in the Earth′s atmosphere. However, several challenges have hindered the commercialization of this technology, including energy efficiency, the solubility of CO2 in the aqueous phase, and electrode stability. In this Minireview, we highlight and summarize the main advantages and limitations that metal–organic frameworks (MOFs) may offer in this field of research, either when used directly as electrocatalysts or when used as catalyst precursors. [ABSTRACT FROM AUTHOR]

Abstract: Membrane separation for gas purification is an energy‐efficient and environment‐friendly technology. However, the development of high performance membranes is still a great challenge. In principle, mixed matrix membranes (MMMs) have the potential to overcome current materials limitations, but in practice there is no straightforward method to match the properties of fillers and polymers (the main components of MMMs) in such a way that the final membrane performance reflects the high performance of the microporous filler and the processability of the continuous polymer phase. This issue is especially important when high flux polymers are utilized. In this work, we demonstrate that the use of small amounts of a glassy polymer in combination with high performance PIM‐1 allow for the preparation of metal–organic framework (MOF)‐based MMMs with superior separation properties and low aging rates under humid conditions, meeting the commercial target for post‐combustion CO2 capture. [ABSTRACT FROM AUTHOR]

Abstract: To gain insight into the influence of metal–organic framework (MOF) fillers and polymers on membrane performance, eight different composites were studied by combining four MOFs and two polymers. MOF materials (NH2‐MIL‐53(Al), MIL‐69(Al), MIL‐96(Al) and ZIF‐94) with various chemical functionalities, topologies, and dimensionalities of porosity were employed as fillers, and two typical polymers with different permeability‐selectivity properties (6FDA‐DAM and Pebax) were selected as matrices. The best‐performing MOF–polymer composites were prepared by loading 25 wt % of MIL‐96(Al) as filler, which improved the permeability and selectivity of 6FDA‐DAM to 32 and 10 %, while for Pebax they were enhanced to 25 and 18 %, respectively. The observed differences in membrane performance in the separation of CO2 from N2 are explained on the basis of gas solubility, diffusivity properties, and compatibility between the filler and polymer phases. [ABSTRACT FROM AUTHOR]

Research into extended porous materials such as metal-organic frameworks (MOFs) and porous organic frameworks (POFs), as well as the analogous metal-organic polyhedra (MOPs) and porous organic cages (POCs), has blossomed over the last decade. Given their chemical and structural variability and notable porosity, MOFs have been proposed as adsorbents for industrial gas separations and also as promising filler components for high-performance mixed-matrix membranes (MMMs). Research in this area has focused on enhancing the chemical compatibility of the MOF and polymer phases by judiciously functionalizing the organic linkers of the MOF, modifying the MOF surface chemistry, and, more recently, exploring how particle size, morphology, and distribution enhance separation performance. Other filler materials, including POFs, MOPs, and POCs, are also being explored as additives for MMMs and have shown remarkable anti-aging performance and excellent chemical compatibility with commercially available polymers. This Review briefly outlines the state-of-the-art in MOF-MMM fabrication, and the more recent use of POFs and molecular additives. [ABSTRACT FROM AUTHOR]

A Co@N-doped carbon (Co@NC) hybrid was synthesized by thermal decomposition of the metal-organic framework (MOF) ZIF-67 under N2 atmosphere. These hybrid materials exhibit outstanding catalytic activity and chemoselectivity for the conversion of a wide range of substituted nitroarenes to their corresponding anilines under relatively mild reaction conditions. The high catalytic performance is attributed to the formation of cobalt nanoparticles and to the presence of atomically dispersed Co species in close interaction with nitrogen-doped graphene. Both active species are formed in situ during the pyrolytic transformation of ZIF-67. The catalysts could be reused in consecutive runs, exhibiting a slightly lower activity ascribed to blockage of the active sites by strongly adsorbed reaction species. These results open up a pathway for the design of noble-metal-free solid catalysts for industrial applications. [ABSTRACT FROM AUTHOR]

In this study, the detection protocols for the individual, selective, and simultaneous determination of ibuprofen (IBP) and diclofenac (DCF) in aqueous solutions have been developed using HKUST-1 metal-organic framework-carbon nanofiber composite (HKUST-CNF) electrode. The morphological and electrical characterization of modified composite electrode prepared by film casting was studied by scanning electronic microscopy and four-point-probe methods. The electrochemical characterization of the electrode by cyclic voltammetry (CV) was considered the reference basis for the optimization of the operating conditions for chronoamperometry (CA) and multiple-pulsed amperometry (MPA). This electrode exhibited the possibility to selectively detect IBP and DCF by simple switching the detection potential using CA. However, the MPA operated under optimum working conditions of four potential levels selected based on CV shape in relation to the potential value, pulse time, and potential level number, and order allowed the selective/simultaneous detection of IBP and DCF characterized by the enhanced detection performance. For this application, the HKUST-CNF electrode exhibited a good stability and reproducibility of the results was achieved. [ABSTRACT FROM AUTHOR]

A study of a copper-based metal–organic framework (MOF) synthesized by an electrochemical route is presented. Morphological and adsorption properties of the MOF synthesized as bulk powder and on supported copper surfaces were investigated. Differences in these properties and structural refinement studies indicate that when 4,4′,4′′-s-triazine-2,4,6-triyl-tribenzoic acid (H3TATB) is used as linker interpenetration can be prevented when the structure is grown on a surface. [ABSTRACT FROM AUTHOR]

Mixed-matrix membranes comprising NH2-MIL-53(Al) and Matrimid or 6FDA-DAM have been investigated. The metal organic framework (MOF) loading has been varied between 5 and 20 wt%, while NH2-MIL-53(Al) with three different morphologies, nanoparticles, nanorods, and microneedles has been dispersed in Matrimid. The synthesized membranes have been tested in the separation of CO2 from CH4 in an equimolar mixture. At 3 bar and 298 K for 8 wt% MOF loading, incorporation of NH2-MIL-53(Al) nanoparticles leads to the largest improvement compared to nanorods and microneedles. The incorporation of the best performing filler, i.e., NH2-MIL-53(Al) nanoparticles, into the highly permeable 6FDA-DAM has a larger effect, and the CO2 permeability increases up to 85% with slightly lower selectivities for 20 wt% MOF loading. Specifically, these membranes have a permeability of 660 Barrer with a CO2/CH4 separation factor of 28, leading to a performance very close to the Robeson limit of 2008. Furthermore, a new non-destructive technique based on Raman spectroscopy mapping is introduced to assess the homogeneity of the filler dispersion in the polymer matrix. The MOF contribution can be calculated by modeling the spectra. The determined homogeneity of the MOF filler distribution in the polymer is confirmed by focused ion beam scanning electron microscopy analysis. [ABSTRACT FROM AUTHOR]

A Cu/PMA-MIL-101(Cr) metal-organic-framework-coated microreactor has been applied in the 1,3-dipolar cycloaddition of benzyl azide and phenylactetylene (click chemistry). The Cu/PMA-MIL-101(Cr) catalyst was incorporated by using a washcoating method. The use of tetraethylorthosilicate (TEOS) and a copolymer pluronic F127 as binders resulted in a stable and uniform coating of 6 μm. The application of the Cu/PMA-MIL-101(Cr) capillary microreactor in the click-chemistry reaction resulted in a similar intrinsic activity as in the batch reactor, and a continuous production for more than 150 h time-on-stream could be achieved. The presence of water in the reagent feed led to reversible catalyst deactivation and was necessary to be removed to obtain a stable catalyst operation. [ABSTRACT FROM AUTHOR]

Recently, MIL-125(Ti) and NH2-MIL-125(Ti), two titanium-based metal-organic frameworks, have attracted significant research attention in the field of photocatalysis for solar fuel generation. This work reveals that the differences between these structures are not only based on their light absorption range but also on the decay profile and topography of their excited states. In contrast to MIL-125(Ti), NH2-MIL-125(Ti) shows markedly longer lifetimes of the charge-separated state, which improves photoconversion by the suppression of competing decay mechanisms. We used spectroelectrochemistry and ultrafast spectroscopy to demonstrate that upon photoexcitation in NH2-MIL-125(Ti) the electron is located in the Ti-oxo clusters and the hole resides on the aminoterephthalate unit, specifically on the amino group. The results highlight the role of the amino group in NH2-MIL-125(Ti), the electron donation of which extends the lifetime of the photoexcited state substantially. [ABSTRACT FROM AUTHOR]

Single-ion magnets (SIMs) are the smallest possible magnetic devices and are a controllable, bottom-up approach to nanoscale magnetism with potential applications in quantum computing and high-density information storage. In this work, we take advantage of the promising, but yet insufficiently explored, solid-state chemistry of metal-organic frameworks (MOFs) to report the single-crystal to single-crystal inclusion of such molecular nanomagnets within the pores of a magnetic MOF. The resulting host-guest supramolecular aggregate is used as a playground in the first in-depth study on the interplay between the internal magnetic field created by the long-range magnetic ordering of the structured MOF and the slow magnetic relaxation of the SIM. [ABSTRACT FROM AUTHOR]

The ability to control the interplay of materials with low-energy photons is important as visible light offers several appealing features compared to ultraviolet radiation (less damaging, more selective, predominant in the solar spectrum, possibility to increase the penetration depth). Two different metal-organic frameworks (MOFs) were synthesized from the same linker bearing all-visible ortho-fluoroazobenzene photoswitches as pendant groups. The MOFs exhibit different architectures that strongly influence the ability of the azobenzenes to isomerize inside the voids. The framework built with Al-based nodes has congested 1D channels that preclude efficient isomerization. As a result, local light-heat conversion can be used to alter the CO2 adsorption capacity of the material on exposure to green light. The second framework, built with Zr nodes, provides enough room for the photoswitches to isomerize, which leads to a unique bistable photochromic MOF that readily responds to blue and green light. The superiority of green over UV irradiation was additionally demonstrated by reflectance spectroscopy and analysis of digested samples. This material offers promising perspectives for liquid-phase applications such as light-controlled catalysis and adsorptive separation. [ABSTRACT FROM AUTHOR]

Keywords: Metal-Organic Frameworks; MOF-derived materials; Photo-Thermal Catalysis; Plasmonics; Solar fuels EN Metal-Organic Frameworks MOF-derived materials Photo-Thermal Catalysis Plasmonics Solar fuels 1 1 1 10/14/22 20221011 NES 221011 B The Front Cover b shows the two routes in which metal-organic frameworks (MOFs) can participate in photo-thermal reactions. In the case of MOF-based composites, MOFs can act as hosts for plasmonic metal nanoparticles that, upon irradiation, are able to drive chemical reactions through high-energy electrons and/or thermal enhancement. In the case of MOF-derived materials, MOFs play a role as sacrificial templates to create new materials based on highly dispersed metal nanoparticles embedded into a carbon matrix. [Extracted from the article]

Thermal treatment of phosphotungstic acid (PTA)-MIL-101(Cr) composites in the presence of hydroformylation catalyst RhH(CO)(PPh3)3 leads to immobilization of the homogeneous Rh complex within the metal-organic framework (MOF) scaffold by coordination of PTA-Rh. The Rh complex-containing MOFs are tested in the hydroformylation of 1-octene in which PTA competes with CO during ligand association. In the presence of the carbonyl ligand, the Rh complex is released from the MOF and behaves as a homogeneous catalyst. Therefore, the product spectra and selectivities of the Rh complex-containing MOFs are similar to those of RhH(CO)(PPh3)3. Upon CO evacuation, Rh recoordinates to PTA, allowing for easy recycling of this new pseudo-heterogeneous catalyst. [ABSTRACT FROM AUTHOR]

Bonding in six-coordinate complexes based on Group 13 elements (B, Al, Ga, In, Tl) is usually considered to be identical to that in transition-metal analogues. We herein demonstrate through sophisticated electronic-structure analyses that the bonding in these Group 13 element complexes is fundamentally different and better characterized as electron-rich hypervalent bonding with essentially no role for the d orbitals. This characteristic is carried through to the molecular properties of the complex. [ABSTRACT FROM AUTHOR]

Incorporation of new functionalities into metal-organic frameworks (MOFs) by post-synthetic modification is a most attractive strategy for attaining the desired properties without risking destruction of the crystalline structure chosen for the aimed application. In this work the amine group in NH2-MIL-53(Al) was used as anchoring point for the diphenylphosphinyl (Ph2PO-) moiety. The success of the derivatization was confirmed by 31P MAS NMR and DRIFT spectroscopic studies. A newly synthesized reference linker bearing the same phosphinic amide functional group was used to assist in the MOF characterization. The introduction of the bulky diphenylphosphinyl group stabilizes the large-pore form of the MOF and leads to changes in the optical properties as a consequence of the electronic influence of the PO group. The approach described here is relevant for the preparation of novel phosphorus-containing MOFs. [ABSTRACT FROM AUTHOR]

In this work, thin films of the well-known metal–organic framework ZIF-8 were formed on zinc oxide nanorods through the reaction with 2-methyl-imidazole solution (Hmim). Deposition of a thin film of the linker solution allows the underlying zinc oxide nanorod morphology to be preserved, resulting in the facile and precise formation of nanostructured hybrid materials in short reaction times and under conventional heating. The effect of various synthesis parameters on the morphology of the resulting thin film is reported. [ABSTRACT FROM AUTHOR]

A preliminary study based on a conceptual process design methodology that includes a technical evaluation and an economic study has been carried out for the use of the metal-organic framework NH2-MIL-53(Al) as adsorbent for the separation of carbon dioxide from methane. Among the alternatives considered, a vacuum pressure swing adsorption was chosen in the detailed design phase. The combination of a design with columns in parallel and the possibility of recirculating some of the streams ensures a high degree of separation and a final product with high quality without compromising the operation costs. A comparison with the state-of-the-art technology, amine scrubbing, and with a process based on membranes demonstrates that the proposed process is competitive as a result of its low operation costs and the energy demand. [ABSTRACT FROM AUTHOR]

A single crystal to single crystal transmetallation process takes place in the three-dimensional (3D) metal-organic framework (MOF) of formula MgII2{MgII4[CuII2(Me3mpba)2]3}⋅45 H2O ( 1; Me3mpba4−= N, N′-2,4,6-trimethyl-1,3-phenylenebis(oxamate)). After complete replacement of the MgII ions within the coordination network and those hosted in the channels by either CoII or NiII ions, 1 is transmetallated to yield two novel MOFs of formulae Co2II{CoII4[CuII2(Me3mpba)2]3}⋅56 H2O ( 2) and Ni2II{NiII4[CuII2(Me3mpba)2]3}⋅ 54 H2O ( 3). This unique postsynthetic metal substitution affords materials with higher structural stability leading to enhanced gas sorption and magnetic properties. [ABSTRACT FROM AUTHOR]

The field of metal–organic framework based mixed matrix membranes (M4s) is critically reviewed, with special emphasis on their application in CO2 capture during energy generation. After introducing the most relevant parameters affecting membrane performance, we define targets in terms of selectivity and productivity based on existing literature on process design for pre- and post-combustion CO2 capture. Subsequently, the state of the art in M4s is reviewed against these targets. Because final application of these membranes will only be possible if thin separation layers can be produced, the latest advances in the manufacture of M4 hollow fibers are discussed. Finally, the recent efforts in understanding the separation performance of these complex composite materials and future research directions are outlined. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are porous crystalline materials consisting of metal ions bound through coordination bonds to organic linkers. Much research over the last few decades have been devoted to the synthesis of these materials in view of their promising applications in, for example, catalysis, separation, gas storage, drug delivery and sensing. Among the variety of methods developed for the synthesis of MOFs are electrochemical techniques. These methods have several advantages such as mild synthesis conditions, shorter synthesis times and the possibility to control the reaction conditions directly during the synthesis process. However, the progress of electrosynthesis methods has lagged behind that of other methods such as solvothermal and microwave-assisted synthesis. In this Review, we summarise and critically assess research on the electrosynthesis of MOFs and provide a full picture of the developments within this field. The various ways in which electrochemistry has contributed to the synthesis of MOFs are explained, their strengths and shortcomings are discussed, and an outlook for future research is provided. [ABSTRACT FROM AUTHOR]

We report a series of powder X-ray diffraction experiments performed on the soft porous crystals MIL-53(Al) and NH2-MIL-53(Al) in a diamond anvil cell under different pressurization media. Systematic refinements of the obtained powder patterns demonstrate that these materials expand along a specific direction while undergoing total volume reduction under an increasing hydrostatic pressure. The results confirm for the first time the negative linear compressibility behaviour of this family of materials, recently predicted from quantum chemical calculations. [ABSTRACT FROM AUTHOR]

Composites incorporating two-dimensional nanostructures within polymeric matrices have potential as functional components for several technologies, including gas separation. Prospectively, employing metal-organic frameworks (MOFs) as versatile nanofillers would notably broaden the scope of functionalities. However, synthesizing MOFs in the form of freestanding nanosheets has proved challenging. We present a bottom-up synthesis strategy for dispersible copper 1,4-benzenedicarboxylate MOF lamellae of micrometre lateral dimensions and nanometre thickness. Incorporating MOF nanosheets into polymer matrices endows the resultant composites with outstanding CO2 separation performance from CO2/CH4 gas mixtures, together with an unusual and highly desired increase in the separation selectivity with pressure. As revealed by tomographic focused ion beam scanning electron microscopy, the unique separation behaviour stems from a superior occupation of the membrane cross-section by the MOF nanosheets as compared with isotropic crystals, which improves the efficiency of molecular discrimination and eliminates unselective permeation pathways. This approach opens the door to ultrathin MOF-polymer composites for various applications. [ABSTRACT FROM AUTHOR]

A straightforward synthetic route to chiral metal-organic frameworks is proposed that relies on an acid-base interaction between an acid linker and a chiral primary amino acid derived diamine organocatalyst. High ee values for the aldol condensation of linear ketones and aromatic aldehydes are reported with this heterogeneous catalyst. Three consecutive catalyst reuse experiments demonstrated that the majority of the activity was preserved, as was the enantioselectivity. [ABSTRACT FROM AUTHOR]

Mixed matrix membranes (MMMs) composed of metal organic framework (MOF) fillers embedded in a polymeric matrix represent a promising alternative for CO2 removal from natural gas and biogas. Here, MMMs based on NH2‐MIL‐53(Al) MOF and polyimide are successfully synthesized with MOF loadings up to 25 wt% and different thicknesses. At 308 K and ΔP = 3 bar, the incorporation of the MOF filler enhances CO2 permeability with respect to membranes based on the neat polymer, while preserving the relatively high separation factor. The rate of solvent evaporation after membrane casting proves key for the final configuration and dispersion of the MOF in the membrane. Fast solvent removal favours the contraction of the MOF structure to its narrow pore framework configuration, resulting in enhanced separation factor and, particularly, CO2 permeability. The study reveals an excellent filler‐polymer contact, with ca. 0.11% void volume fraction, for membranes based on the amino‐functionalized MOF, even at high filler loadings (25 wt%). By providing precise and quantitative insight into key structural features at the nanoscale range, the approach provides feedback to the membrane casting process and therefore it represents an important advancement towards the rational design of mixed matrix membranes with enhanced structural features and separation performance. [ABSTRACT FROM AUTHOR]

Reticular design is a highly attractive concept, but coordination chemistry around the tectonic units of metal–organic frameworks (MOFs) and additional interplay with anionic and solvent species provide for dazzling complexity that effectively rules out structure prediction. We can however study the chemistry around pre-existing clusters, and assemble novel materials correspondingly, using a priori information about the connectivity of an investigated metal cluster. Studies, often spectroscopic of nature, have in recent years solved many puzzles in MOF crystallization. The obtained knowledge opens new doors in crystal engineering, but more research on MOF coordination chemistry has to be carried out. [ABSTRACT FROM AUTHOR]

We present an in situ small- and wide-angle X-ray scattering (SAXS/WAXS) and quick-scanning extended X-ray absorption fine-structure (QEXAFS) spectroscopy study on the crystallization of the metal-organic framework ZIF-7. In combination with DFT calculations, the self-assembly and growth of ZIF-7 microrods together with the chemical function of the crystal growth modulator (diethylamine) are revealed at all relevant length scales, from the atomic to the full crystal size. [ABSTRACT FROM AUTHOR]

The one-pot encapsulation of phosphotungstic acid in the metal–organic framework MIL-100(Cr) has been studied under different synthesis conditions. Both conventional and microwave heating methods have been explored for three different solvent systems: pure aqueous or organic (DMF) phase and biphasic mixtures (water/2-pentanol). Biphasic systems yielded crystals with similar textural properties as those formed in water. The use of DMF as solvent promotes the formation of gel-like solids with dual porosity and enhanced accessibility. The addition of phosphotungstic acid (PTA, H3PW12O40.xH2O) to the MIL-100(Cr) synthesis mixture results in its direct encapsulation. 31P MAS NMR, elemental analysis, N2 adsorption and FT-IR spectroscopy confirm the incorporation of PTA in the sample. The highest PTA encapsulation loading (30 wt%) was obtained by synthesis with microwave heating in biphasic solvent systems (W/Cr molar ratio range between 0.5 and 0.25). Microwave irradiation decreases the time of synthesis (from 4 days to 3 hours) while the use of biphasic media preserves the PTA integrity without affecting the formation of the MOF. The interaction of PTA with the MIL-100(Cr) structure results in some loss of the Lewis acidity, while the Brønsted acidity is hardly affected. [ABSTRACT FROM AUTHOR]

Abstract: Metal-organic frameworks (MOFs) with non-coordinated amino groups, i.e. IRMOF-3 and amino-functionalized MIL-53, are stable solid basic catalysts in the Knoevenagel condensation of ethyl cyanoacetate and ethyl acetoacetate with benzaldehyde. IRMOF-3DEF exhibits activities that are at least as high as the most active solid basic catalysts reported, with a 100% selectivity to the condensation product. For IRMOF-3 samples the catalytic activity correlated with the accessibility of the basic sites. Diffusion limitations could be excluded for this most active catalyst. A new MOF based on the MIL-53 topology and non-coordinated amino groups has been synthesized and characterized. Although active its poor performance in the studied Knoevenagel condensations is attributed to strong adsorption and diffusion limitations in the 1-D pore structure of this framework. The performance of the IRMOF-3 catalysts demonstrates that the basicity of the aniline-like amino group is enhanced when incorporated inside the MOF structure, increasing the of the basic catalyst and more active than aniline as homogeneous catalyst. The IRMOF-3 catalysts are stable under the studied reaction conditions, and could be reused without significant loss in activity. The catalytic performance of IRMOF-3 in various solvents suggests that this open, accessible and well-defined structure behaves more like homogeneous basic catalysts, in contrast to other solid basic catalysts. By means of DRIFTS, the reaction mechanism has been elucidated, showing spectroscopic evidence of benzaldimine intermediates. [Copyright &y& Elsevier]

Heterogeneous Catalysis In their Communication on page 26476, Luis Garzón‐Tovar, Jorge Gascon et al. report a metal–organic framework‐derived nickel catalyst for the light driven methanation of CO2. [ABSTRACT FROM AUTHOR]

Carbon dioxide, metal-organic frameworks, methanation, photothermal catalysis, pyrolysis Frontispiece: An Efficient Metal-Organic Framework-Derived Nickel Catalyst for the Light Driven Methanation of CO2 Keywords: carbon dioxide; metal-organic frameworks; methanation; photothermal catalysis; pyrolysis EN carbon dioxide metal-organic frameworks methanation photothermal catalysis pyrolysis 1 1 1 12/07/21 20211213 NES 211213 B Heterogeneous Catalysis b In their Communication on page 26476, Luis Garzón-Tovar, Jorge Gascon et al. report a metal-organic framework-derived nickel catalyst for the light driven methanation of CO SB 2 sb . [Extracted from the article]

Carbon dioxide, metal-organic frameworks, methanation, photothermal catalysis, pyrolysis Frontispiz: An Efficient Metal-Organic Framework-Derived Nickel Catalyst for the Light Driven Methanation of CO2 Keywords: carbon dioxide; metal-organic frameworks; methanation; photothermal catalysis; pyrolysis EN carbon dioxide metal-organic frameworks methanation photothermal catalysis pyrolysis 1 1 1 12/09/21 20211213 NES 211213 B Heterogene Katalyse b In der Zuschrift auf S. 26680 berichten Luis Garzón-Tovar, Jorge Gascon et al. über einen aus einer metall-organischen Gerüstverbindung hergestellten Nickelkatalysator für die photochemische Methanierung von CO SB 2 sb . [Extracted from the article]

Dry reforming of methane (DRM) involves the conversion of CO2 and CH4, the most important greenhouse gases, into syngas, a stoichiometric mixture of H2 and CO that can be further processed via Fischer–Tropsch chemistry into a wide variety of products. However, the devolvement of the coke resistant catalyst, especially at high pressures, is still hampering commercial applications. One of the relatively new approaches for the synthesis of metal nanoparticle based catalysts comprises the use of metal-organic frameworks (MOFs) as catalyst precursors. In this work we have explored MOF-74/CPO-27 MOFs as precursors for the synthesis of Ni, Co and bimetallic Ni-Co metal nanoparticles. Our results show that the bimetallic system produced through pyrolysis of a Ni-Co@CMOF-74 precursor displays the best activity at moderate pressures, with stable performance during at least 10 h at 700 °C, 5 bar and 33 L·h−1·g−1. [ABSTRACT FROM AUTHOR]

Solid ‐ state incorporation of a single ‐ ion magnet (SIM) within the pores of a magnetic 3D metal – organic framework (MOF) in a single ‐ crystal to single ‐ crystal process has been demonstrated. The resulting host – guest supramolecular aggregate affords the first deep study on the interplay of the internal magnetic field of the MOF and the slow magnetic relaxation of the SIM allowing the observation of a partial suppression of the quantum ‐ tunneling effects operative in the SIM. More information can be found in the Full Paper by D. Armentano, E. Pardo et al. on page 539 ff. [ABSTRACT FROM AUTHOR]

Review: 203 refs. [ABSTRACT FROM AUTHOR]

We report the synthesis of a highly active and stable metal‐organic framework derived Ni‐based catalyst for the photothermal reduction of CO2 to CH4. Through the controlled pyrolysis of MOF‐74 (Ni), the nature of the carbonaceous species and therefore photothermal performance can be tuned. CH4 production rates of 488 mmol g−1 h−1 under UV‐visible‐IR irradiation are achieved when the catalyst is prepared under optimized conditions. No particle aggregation or significant loss of activity were observed after ten consecutive reaction cycles or more than 12 hours under continuous flow configuration. Finally, as a proof‐of‐concept, we performed an outdoor experiment under ambient solar irradiation, demonstrating the potential of our catalyst to reduce CO2 to CH4 using only solar energy. [ABSTRACT FROM AUTHOR]

We report the synthesis of a highly active and stable metal‐organic framework derived Ni‐based catalyst for the photothermal reduction of CO2 to CH4. Through the controlled pyrolysis of MOF‐74 (Ni), the nature of the carbonaceous species and therefore photothermal performance can be tuned. CH4 production rates of 488 mmol g−1 h−1 under UV‐visible‐IR irradiation are achieved when the catalyst is prepared under optimized conditions. No particle aggregation or significant loss of activity were observed after ten consecutive reaction cycles or more than 12 hours under continuous flow configuration. Finally, as a proof‐of‐concept, we performed an outdoor experiment under ambient solar irradiation, demonstrating the potential of our catalyst to reduce CO2 to CH4 using only solar energy. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ti-based Metal-Organic Framework, ACM-1, fluorination mediated by trifluoroacetic acid is presented. • The presence of F-species enhances the photocatalytic activity in the hydrogen evolution reaction. • Improved activity was attributed to the extended light absorption and increased charge capacitance. Defect engineering has emerged as a promising strategy to enhance the photocatalytic properties of metal–organic frameworks (MOFs). In this study, we investigate the influence of the introduction of defects into a Ti-based MOF, ACM-1, on its photocatalytic activity for hydrogen evolution reaction. Through solid-state NMR and XPS analysis, we define the structural defects as a fluoride inclusion. Our results demonstrate a remarkable 5-fold increase in photocatalytic activity compared to pristine ACM-1. Density functional theory (DFT) calculations reveal that the presence of fluorine atoms stabilizes titanium orbitals, leading to a reduced band gap. This reduction in the band gap is identified as the key mechanism underlying the enhanced photocatalytic activity. Our findings highlight the efficacy of defect engineering through TFA-mediated fluoride inclusion in improving the photocatalytic performance of Ti-based MOF ACM-1. [ABSTRACT FROM AUTHOR]