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Purification and storage of acetylene (C2H2) are important to many industrial processes. The exploitation of metal -organic framework (MOF) materials to address the balance between selectivity for C2H2 vs carbon dioxide (CO2 ) against maximising uptake of C2H2 has attracted much interest. Herein, we report that the synergy between unsaturated copper (II) sites and functional groups, fluoro (-F), methyl (-CH3), nitro (-NO2) in a series of isostructural MOF materials MFM-190(R) that show exceptional adsorption and selectivity of C2H2 . At 298 K, MFM-190(NO2) exhibits an C2H2 uptake of 216 cm3 g-1 (320 cm3 g-1 at 273 K ) at 1.0 bar and a high selectivity for C2H2/CO2 (up to ~150 for v/v = 2/1) relevant to that in the industrial cracking stream. Dynamic breakthrough studies validate and confirm the excellent separation of C2H2/CO2 by MFM-190(NO2) under ambient conditions. In situ neutron powder diffraction reveals the cooperative binding, packing and selectivity of C2H2 by unsaturated Cu(II) sites and free -NO2 groups., (© 2024 Wiley‐VCH GmbH.)

Ammonia (NH 3 ) production in 2023 reached 150 million tons and is associated with potential concomitant production of up to 500 million tons of CO 2 each year. Efforts to produce green NH 3 are compromised since it is difficult to separate using conventional condensation chillers, but in situ separation with minimal cooling is challenging. While metal-organic framework materials offer some potential, they are often unstable and decompose in the presence of caustic and corrosive NH 3 . Here, we address these challenges by developing a pore-expansion strategy utilizing the flexible phosphonate framework, STA-12(Ni), which shows exceptional stability and capture of NH 3 at ppm levels at elevated temperatures (100-220 °C) even under humid conditions. A remarkable NH 3 uptake of 4.76 mmol g -1 at 100 μbar (equivalent to 100 ppm) is observed, and in situ neutron powder diffraction, inelastic neutron scattering, and infrared microspectroscopy, coupled with modeling, reveal a pore expansion from triclinic to a rhombohedral structure on cooperative binding of NH 3 to unsaturated Ni(II) sites and phosphonate groups. STA-12(Ni) can be readily engineered into pellets or monoliths without losing adsorption capacity, underscoring its practical potential.

Capture of trace benzene is an important and challenging task. Metal-organic framework materials are promising sorbents for a variety of gases, but their limited capacity towards benzene at low concentration remains unresolved. Here we report the adsorption of trace benzene by decorating a structural defect in MIL-125-defect with single-atom metal centres to afford MIL-125-X (X = Mn, Fe, Co, Ni, Cu, Zn; MIL-125, Ti 8 O 8 (OH) 4 (BDC) 6 where H 2 BDC is 1,4-benzenedicarboxylic acid). At 298 K, MIL-125-Zn exhibits a benzene uptake of 7.63 mmol g -1 at 1.2 mbar and 5.33 mmol g -1 at 0.12 mbar, and breakthrough experiments confirm the removal of trace benzene (from 5 to <0.5 ppm) from air (up to 111,000 min g -1 of metal-organic framework), even after exposure to moisture. The binding of benzene to the defect and open Zn(II) sites at low pressure has been visualized by diffraction, scattering and spectroscopy. This work highlights the importance of fine-tuning pore chemistry for designing adsorbents for the removal of air pollutants., (© 2024. The Author(s).)

Phenylacetylene is a detrimental impurity in the polymerisation of styrene, capable of poisoning catalysts even at ppm levels and significantly degrading the quality of polystyrene. The semi-hydrogenation of phenylacetylene to styrene instead of ethylbenzene is, therefore, an important industrial process. We report a novel cerium(iv)-based metal-organic framework (denoted as Ce-bptc), which comprises {Ce 6 } clusters bridged by biphenyl-3,3',5,5'-tetracarboxylate linkers. Ce-bptc serves as an ideal support for palladium nanoparticles and the Pd@Ce-bptc catalyst demonstrates excellent catalytic performance for semi-hydrogenation of phenylacetylene, achieving a selectivity of 93% towards styrene on full conversion under ambient conditions with excellent reusability. In situ synchrotron X-ray powder diffraction and electron paramagnetic resonance spectroscopy reveal the binding domains of phenylacetylene within Ce-bptc, and details of the reaction mechanism are discussed., Competing Interests: The authors declare no conflicts of interest., (This journal is © the Partner Organisations.)

We report the high NH 3 uptake in a series of copper-carboxylate materials, namely MFM-100, MFM-101, MFM-102, MFM-126, MFM-127, MFM-190(F), MFM-170, and Cu-MOP-1a. At 273 K and 1 bar, MFM-101 shows an exceptional uptake of 21.9 mmol g -1 . The presence of Cu(II)⋯NH 3 interactions and changes in coordination at the [Cu 2 (O 2 CR) 4 ] paddlewheel are analysed and discussed.

The selective oxidation of olefins by molecular oxygen holds great importance in the chemical industry due to its remarkable adaptability in constructing carbonyl compounds. Classical homogeneous Wacker oxidation with a complex system of PdCl 2 -CuCl 2 -H 2 O is currently employed in the industrial production of acetaldehyde, which suffers from several key drawbacks. The development of alternative heterogeneous catalytic systems for Wacker-type oxidations has been hotly pursued for decades. Herein, we report a novel heterogeneous catalyst, namely Pd@FAU containing exclusive singular Pd sites confined in zeolite, showing remarkable performance in the Wacker-type oxidation of light olefins to the corresponding carbonyl compounds. Typically, stable propylene conversion rates of 2.3-3.5 mol/mol Pd /min and an acetone selectivity of 75-89% can be achieved simultaneously, surpassing the state-of-the-art homogeneous Wacker oxidation systems. In situ spectroscopic investigations disclose the spontaneous redox cycle of Pd + -Pd 2+ -Pd + in Pd@FAU during the reaction, in significant contrast to the known Pd 2+ -Pd 0 -Pd 2+ redox cycle. Theoretical calculations reveal the unique reaction pathway and mechanism of Wacker-type oxidation over Pd@FAU, without the participation of water as the nucleophile. Overall, a novel heterogeneous catalyst of Pd@FAU has been developed for Wacker-type oxidations with the unique reaction mechanism fully interpreted. This study will contribute to more sustainable Wacker-type oxidations and further improve the current understanding of Pd redox catalysis.

Since the advent of the Haber-Bosch process in 1910, the global demand for ammonia (NH 3 ) has surged, driven by its applications in agriculture, pharmaceuticals, and energy. Current methods of NH 3 storage, including high-pressure storage and transportation, present significant challenges due to their corrosive and toxic nature. Consequently, research has turned towards metal-organic framework (MOF) materials as potential candidates for NH 3 storage due to their potential high adsorption capacities and structural tunability. MOFs are coordination networks composed of metal nodes and organic linkers, offering unprecedented porosity and surface area, and allowing incorporation of various functional groups and metal sites that can enhance NH 3 adsorption. However, the stability of MOFs in the presence of NH 3 is a significant concern since many degrade upon exposure to NH 3 , primarily due to ligand displacement and framework collapse. To address this, recent studies have focused on the synthesis and postsynthetic modification of MOFs to enhance both NH 3 uptake and stability. In this Account, we summarize recent developments in the design and characterization of MOFs for NH 3 storage. The choice of metal centers in MOFs is crucial for stability and performance. High-valence metals such as Al III and Ti IV form strong metal-linker bonds, enhancing the stability of the framework to NH 3 . The MFM-300 series of materials composed of high-valence 3+ and 4+ metal ions and carboxylic linkers demonstrates high stability and high NH 3 uptake capacities. Ligand functionalization is another effective strategy for improving the NH 3 adsorption. Polar functional groups such as -NH 2 , -OH, and -COOH enhance the interaction between the framework and NH 3 , particularly at low partial pressures, while postsynthetic modification allows fine-tuning of these functionalities to optimize the framework for higher adsorption capacities and stability. For example, MFM-303(Al), incorporating free carboxylic acid groups, exhibits a high NH 3 packing density comparable to that of solid NH 3 . Creating defect sites by removing linkers or adding metal ions increases the number of active sites available for NH 3 adsorption and shows promise for enhancing uptake. UiO-66, a stable MOF framework, can be modified to include defect sites, significantly enhancing the level of NH 3 uptake. The full characterization of MOFs and especially their interactions with NH 3 are vital for understanding and improving their performance. Techniques such as neutron powder diffraction (NPD), inelastic neutron scattering (INS), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), electron paramagnetic resonance (EPR) spectroscopy, and solid-state nuclear magnetic resonance (ssNMR) spectroscopy can elucidate host-guest interactions and binding dynamics between NH 3 and the framework structure and afford crucial information for the future design and rational development of new sorbents. This Account highlights our current strategies for the synthesis and characterization of MOFs for NH 3 capture, providing an overview of this rapidly evolving field., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Co-published by ShanghaiTech University and American Chemical Society.)

The functionalization of metal-organic frameworks (MOFs) to enhance the adsorption of benzene at trace levels remains a significant challenge. Here, we report the exceptional adsorption of trace benzene in a series of zirconium-based MOFs functionalized with chloro groups. Notably, MFM-68-Cl 2 , constructed from an anthracene linker incorporating chloro groups, exhibits a remarkable benzene uptake of 4.62 mmol g -1 at 298 K and 0.12 mbar, superior to benchmark materials. In situ synchrotron X-ray diffraction, Fourier transform infrared microspectroscopy, and inelastic neutron scattering, coupled with density functional theory modeling, reveal the mechanism of binding of benzene in these materials. Overall, the excellent adsorption performance is promoted by an unprecedented cooperation between chloro-groups, the optimized pore size, aromatic functionality, and the flexibility of the linkers in response to benzene uptake in MFM-68-Cl 2 . This study represents the first example of enhanced adsorption of trace benzene promoted by -C H ···Cl and Cl···π interactions in porous materials.

Due to almost identical boiling points of benzene and cyclohexane, the extraction of trace benzene from cyclohexane is currently performed via the energy-intensive extractive distillation method. Their adsorptive separation by porous materials is hampered by their similar dimensions. Metal-organic frameworks (MOFs) with versatile pore environments are capable of molecular discrimination, but the separation of trace substrates in liquid-phase remains extremely challenging. Herein, we report a robust MOF (NKU-300) with triangular channels decorated with crown ether that can discriminate trace benzene from cyclohexane, exhibiting an unprecedented selectivity of 8615(10) for the mixture of benzene/cyclohexane (v/v = 1/1000). Remarkably, NKU-300 demonstrates exceptional selectivities for the extraction of benzene from cyclohexane over a wide range of concentrations of 0.1%-50% with ultrafast sorption kinetics and excellent stability. Single-crystal X-ray diffraction and computational modelling reveal that multiple supramolecular interactions cooperatively immobilise benzene molecules in the triangular channel, enabling superior separation performance. This study will promote the application of advanced sorbents with tailored binding sites for challenging industrial separations., (© The Author(s) 2024. Published by Oxford University Press on behalf of China Science Publishing & Media Ltd.)

Metagenomic analyses facilitate the exploration of the microbial world, advancing our understanding of microbial roles in ecological and biological processes. A pivotal aspect of metagenomic analysis involves assessing the quality of metagenome-assembled genomes (MAGs), crucial for accurate biological insights. Current machine learning-based methods often treat completeness and contamination prediction as separate tasks, overlooking their inherent relationship and limiting models' generalization. In this study, we present DeepCheck, a multitasking deep learning framework for simultaneous prediction of MAG completeness and contamination. DeepCheck consistently outperforms existing tools in accuracy across various experimental settings and demonstrates comparable speed while maintaining high predictive accuracy even for new lineages. Additionally, we employ interpretable machine learning techniques to identify specific genes and pathways that drive the model's predictions, enabling independent investigation and assessment of these biological elements for deeper insights., (© The Author(s) 2024. Published by Oxford University Press.)

Stimuli-responsive physisorbents that undergo reversible structural transformations induced by external stimuli (e.g. light, guests, or heat) offer the promise of utility in gas storage and separation. Whereas reports on guest or light-responsive sorbents have increased in recent years, we are unaware of reports on sorbents that exhibit both light and guest-induced structural transformations. Herein, we report that the square lattice, sql, topology coordination network Zn(fba)(bis) ⋅ 2DMF (sql-5,6-Zn-α, 5=trans-4,4'-bis(1-imidazolyl)stilbene=bis, 6=2,2-bis(4-carboxyphenyl)hexafluoropropane=H 2 fba) underwent single-crystal-to-single-crystal transformation (SCSC) upon activation, affording nonporous sql-5,6-Zn-β. Parallel alignment at 3.23 Å of olefinic moieties on adjacent bis ligands in sql-5,6-Zn-α enabled SCSC [2+2] photocycloaddition upon exposure to UV light (365 nm) or sunlight. sql-5,6-Zn-α thereby transformed to mot-5,6-Zn-α, which was subsequently activated to the narrow pore phase mot-5,6-Zn-β. sql-5,6-Zn-β and mot-5,6-Zn-β both exhibited S-shaped adsorption isotherms characteristic of guest-induced structural changes when exposed to CO 2 at 195 K (type-F-IV and type F-I, respectively). Cycling experiments conducted upon sql-5,6-Zn-β reduced particle size after cycle 1 and induced transformation into a rare example of a shape memory coordination network, sql-5,6-Zn-γ. Insight into this smorgasbord of SCSC phase changes was gained from in situ PXRD, single crystal XRD and 1 H NMR spectroscopy experiments., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

This work reports the thermal and electron beam stabilities of a series of isostructural metal-organic frameworks (MOFs) of type MFM-300(M) (M = Al, Ga, In, Cr). MFM-300(Cr) was most stable under the electron beam, having an unusually high critical electron fluence of 1111 e - Å -2 while the Group 13 element MOFs were found to be less stable. Within Group 13, MFM-300(Al) had the highest critical electron fluence of 330 e - Å -2 , compared to 189 e - Å -2 and 147 e - Å -2 for the Ga and In MOFs, respectively. For all four MOFs, electron beam-induced structural degradation was independent of crystal size and was highly anisotropic, although both the length and width of the channels decreased during electron beam irradiation. Notably, MFM-300(Cr) was found to retain crystallinity while shrinking up to 10%. Thermal stability was studied using in situ synchrotron X-ray diffraction at elevated temperature, which revealed critical temperatures for crystal degradation to be 605, 570, 490 and 480 °C for Al, Cr, Ga, and In, respectively. The pore channel diameters contracted by ≈0.5% on desorption of solvent species, but thermal degradation at higher temperatures was isotropic. The observed electron stabilities were found to scale with the relative inertness of the cations and correlate well to the measured lifetime of the materials when used as photocatalysts., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The fungal disease caused by Magnaporthe oryzae is one of the most devastating diseases that endanger many crops worldwide. Evidence shows that sexual reproduction can be advantageous for fungal diseases as hybridization facilitates host-jumping. However, the pervasive clonal lineages of M. oryzae observed in natural fields contradict this expectation. A better understanding of the roles of recombination and the fungi-specific repeat-induced point mutation (RIP) in shaping its evolutionary trajectory is essential to bridge this knowledge gap. Here we systematically investigate the RIP and recombination landscapes in M. oryzae using a whole genome sequencing data from 252 population samples and 92 cross progenies. Our data reveal that the RIP can robustly capture the population history of M. oryzae, and we provide accurate estimations of the recombination and RIP rates across different M. oryzae clades. Significantly, our results highlight a parent-of-origin bias in both recombination and RIP rates, tightly associating with their sexual potential and variations of effector proteins. This bias suggests a critical trade-off between generating novel allelic combinations in the sexual cycle to facilitate host-jumping and stimulating transposon-associated diversification of effectors in the asexual cycle to facilitate host coevolution. These findings provide unique insights into understanding the evolution of blast fungus., Competing Interests: Conflict of interest The authors declare no conflict of interest., (Copyright © 2024 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Ltd. All rights reserved.)

Mixed matrix membranes represent an important technology for gas separations. Nanosheets of metal-organic framework (MOF) materials of high aspect ratio and size-selective gas transport properties have the potential to promote the efficient mixing of components to form membranes for gas separation. Herein, we report a bottom-up synthesis of extended sheets of kagomé (kgm) topology, kgm t -Bu , via the linkage of [Cu 2 (O 2 CR) 4 ] paddlewheels with 5- tert -butylisophthalic acid. The growth of the layered structure can be controlled by the choice of solvent and modulator. Nanosheets of kgm t -Bu of average thickness of 20 nm and aspect ratio of 40 to 50 can be obtained, and the sieving effect of the channels in kgm t -Bu boost the efficient separation of CO 2 over CH 4 . A mixed matrix membrane comprising kgm t -Bu nanosheets with Matrimid shows a 32% enhancement in CO 2 /CH 4 selectivity compared with the membrane incorporating the MOF in the particulate form.

We report the high adsorption of NH 3 in a titanium-based metal-organic framework, MFM-300(Ti), comprising extended [TiO 6 ] ∞ chains linked by biphenyl-3,3',5,5'-tetracarboxylate ligands. At 273 K and 1 bar, MFM-300(Ti) shows an exceptional NH 3 uptake of 23.4 mmol g -1 with a record-high packing density of 0.84 g cm -3 . Dynamic breakthrough experiments confirm the excellent uptake and separation of NH 3 at low concentration (1000 ppm). The combination of in situ neutron powder diffraction and spectroscopic studies reveal strong, yet reversible binding interactions of NH 3 to the framework oxygen sites.

Conversion of plastic wastes to valuable carbon resources without using noble metal catalysts or external hydrogen remains a challenging task. Here we report a layered self-pillared zeolite that enables the conversion of polyethylene to gasoline with a remarkable selectivity of 99% and yields of >80% in 4 h at 240 °C. The liquid product is primarily composed of branched alkanes (selectivity of 72%), affording a high research octane number of 88.0 that is comparable to commercial gasoline (86.6). In situ inelastic neutron scattering, small-angle neutron scattering, solid-state nuclear magnetic resonance, X-ray absorption spectroscopy and isotope-labelling experiments reveal that the activation of polyethylene is promoted by the open framework tri-coordinated Al sites of the zeolite, followed by β-scission and isomerization on Brönsted acids sites, accompanied by hydride transfer over open framework tri-coordinated Al sites through a self-supplied hydrogen pathway to yield selectivity to branched alkanes. This study shows the potential of layered zeolite materials in enabling the upcycling of plastic wastes., (© 2024. The Author(s).)

Optimization of active sites and stability under irradiation are important targets for sorbent materials that might be used for iodine (I 2 ) storage. Herein, we report the direct observation of I 2 binding in a series of Cu(II)-based isostructural metal-organic frameworks, MFM-170, MFM-172, MFM-174, NJU-Bai20, and NJU-Bai21, incorporating various functional groups (-H, -CH 3 , - NH 2 , -C≡C-, and -CONH-, respectively). MFM-170 shows a reversible uptake of 3.37 g g -1 and a high packing density of 4.41 g cm -3 for physiosorbed I 2 . The incorporation of -NH 2 and -C≡C- moieties in MFM-174 and NJU-Bai20, respectively, enhances the binding of I 2 , affording uptakes of up to 3.91 g g -1 . In addition, an exceptional I 2 packing density of 4.83 g cm -3 is achieved in MFM-174, comparable to that of solid iodine (4.93 g cm -3 ). In situ crystallographic studies show the formation of a range of supramolecular and chemical interactions [I···N, I···H 2 N] and [I···C≡C, I-C═C-I] between -NH 2 , -C≡C- sites, respectively, and adsorbed I 2 molecules. These observations have been confirmed via a combination of solid-state nuclear magnetic resonance, X-ray photoelectron, and Raman spectroscopies. Importantly, γ-irradiation confirmed the ultraresistance of MFM-170, MFM-174, and NJU-Bai20 suggesting their potential as efficient sorbents for cleanup of radioactive waste.

The high structural diversity and porosity of metal-organic frameworks (MOFs) promote their applications in selective gas adsorption. The development of robust MOFs that are stable against corrosive SO 2 remains a daunting challenge. Here, we report a highly robust aluminum-based MOF (HIAM-330) built on a 4-connected Al 3 (OH) 2 (COO) 4 cluster and 8-connected octacarboxylate ligand with a (4,8)-connected scu topology. It exhibits a fully reversible SO 2 uptake of 12.1 mmol g -1 at 298 K and 1 bar. It is capable of selective capture of SO 2 over other gases (CO 2 , CH 4 , and N 2 ) with high adsorption selectivities of 60, 330, and 3537 for equimolar mixtures of SO 2 /CO 2 , SO 2 /CH 4 , and SO 2 /N 2 , respectively, at 298 K and 1 bar. Breakthrough measurements verified the capability of HIAM-330 for selective capture of SO 2 (2500 ppm) over CO 2 or N 2 . High-resolution synchrotron X-ray powder diffraction of SO 2 loaded HIAM-330 revealed the binding domains of adsorbed SO 2 molecules and host-guest interactions., Competing Interests: The authors declare that they have no competing interests., (This journal is © The Royal Society of Chemistry.)

The functionalisation of organic linkers in metal-organic frameworks (MOFs) to improve gas uptake is well-documented. Although the positive role of free carboxylic acid sites in MOFs for binding gas molecules has been proposed in computational studies, relatively little experimental evidence has been reported in support of this. Primarily this is because of the inherent synthetic difficulty to prepare MOF materials bearing free, accessible -COOH moieties which would normally bind to metal ions within the framework structure. Here, we describe the direct binding of CO 2 and C 2 H 2 molecules to the free -COOH sites within the pores of MFM-303(Al). MFM-303(Al) exhibits highly selective adsorption of CO 2 and C 2 H 2 with a high selectivity for C 2 H 2 over C 2 H 4 . In situ synchrotron X-ray diffraction and inelastic neutron scattering, coupled with modelling, highlight the cooperative interactions of adsorbed CO 2 and C 2 H 2 molecules with free -COOH and -OH sites within MFM-303(Al), thus rationalising the observed high selectivity for gas separation., Competing Interests: The authors declare no competing interest., (This journal is © The Royal Society of Chemistry.)

The selective capture of methane (CH 4 ) at low concentrations and its separation from N 2 are extremely challenging owing to the weak host-guest interactions between CH 4 molecules and any sorbent material. Here, we report the exceptional adsorption of CH 4 at low pressure and the efficient separation of CH 4 /N 2 by MFM-300(Fe). MFM-300(Fe) shows a very high uptake for CH 4 of 0.85 mmol g -1 at 1 mbar and 298 K and a record CH 4 /N 2 selectivity of 45 for porous solids, representing a new benchmark for CH 4 capture and CH 4 /N 2 separation. The excellent separation of CH 4 /N 2 by MFM-300(Fe) has been confirmed by dynamic breakthrough experiments. In situ neutron powder diffraction, and solid-state nuclear magnetic resonance and diffuse reflectance infrared Fourier transform spectroscopies, coupled with modelling, reveal a unique and strong binding of CH 4 molecules involving Fe-OH⋯CH 4 and C⋯phenyl ring interactions within the pores of MFM-300(Fe), thus promoting the exceptional adsorption of CH 4 at low pressure., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Heterojunctions combining two photocatalysts of staggered conduction and valence band energy levels can increase the photocatalytic efficiency compared to their individual components. This activity enhancement is due to the minimization of undesirable charge recombination by the occurrence of carrier migration through the heterojunction interface with separated electrons and holes on the reducing and oxidizing junction component, respectively. Metal-organic frameworks (MOFs) are currently among the most researched photocatalysts due to their tunable light absorption, facile charge separation, large surface area and porosity. The present review summarizes the current state-of-the-art in MOF-based heterojunctions, providing critical comments on the construction of these heterostructures. Besides including examples showing the better performance of MOF heterojunctions for three important photocatalytic processes, such as hydrogen evolution reaction, CO 2 photoreduction and dye decolorization, the focus of this review is on describing synthetic procedures to form heterojunctions with MOFs and on discussing the experimental techniques that provide evidence for the operation of charge migration between the MOF and the other component. Special attention has been paid to the design of rational MOF heterojunctions with small particle size and controlled morphology for an appropriate interfacial contact. The final section summarizes the achievements of the field and provides our views on future developments.

Formamides are important feedstocks for the manufacture of many fine chemicals. State-of-the-art synthesis of formamides relies on the use of an excess amount of reagents, giving copious waste and thus poor atom-economy. Here, we report the first example of direct synthesis of N-formamides by coupling two challenging reactions, namely reductive amination of carbonyl compounds, particularly biomass-derived aldehydes and ketones, and fixation of CO 2 in the presence of H 2 over a metal-organic framework supported ruthenium catalyst, Ru/MFM-300(Cr). Highly selective production of N-formamides has been observed for a wide range of carbonyl compounds. Synchrotron X-ray powder diffraction reveals the presence of strong host-guest binding interactions via hydrogen bonding and parallel-displaced π⋅⋅⋅π interactions between the catalyst and adsorbed substrates facilitating the activation of substrates and promoting selectivity to formamides. The use of multifunctional porous catalysts to integrate CO 2 utilisation in the synthesis of formamide products will have a significant impact in the sustainable synthesis of feedstock chemicals., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Dietary exposure to methylmercury (MeHg) causes irreversible damage to human cognition and is mitigated by photolysis and microbial demethylation of MeHg. Rice (Oryza sativa L.) has been identified as a major dietary source of MeHg. However, it remains unknown what drives the process within plants for MeHg to make its way from soils to rice and the subsequent human dietary exposure to Hg. Here we report a hidden pathway of MeHg demethylation independent of light and microorganisms in rice plants. This natural pathway is driven by reactive oxygen species generated in vivo, rapidly transforming MeHg to inorganic Hg and then eliminating Hg from plants as gaseous Hg°. MeHg concentrations in rice grains would increase by 2.4- to 4.7-fold without this pathway, which equates to intelligence quotient losses of 0.01-0.51 points per newborn in major rice-consuming countries, corresponding to annual economic losses of US$30.7-84.2 billion globally. This discovered pathway effectively removes Hg from human food webs, playing an important role in exposure mitigation and global Hg cycling., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

MFM-520(Zn) confines dimers of NO 2 with a high adsorption of 4.52 mmol g -1 at 1 bar at 298 K. The synthesis and the incommensurate structure of Cu-doped MFM-520(Zn) are reported. The introduction of paramagnetic Cu 2+ sites allows investigation of the electronic and geometric structure of metal site by in situ electron paramagnetic resonance (EPR) spectroscopy upon adsorption of NO 2 . By combining continuous wave and electron-nuclear double resonance spectroscopy, an unusual reverse Berry distorted coordination geometry of the Cu 2+ centers is observed. Interestingly, Cu-doped MFM-520(Zn 0.95 Cu 0.05 ) shows enhanced adsorption of NO 2 of 5.02 mmol g -1 at 1 bar at 298 K. Whereas MFM-520(Zn) confines adsorbed NO 2 as N 2 O 4 , the presence of monomeric NO 2 at low temperature suggests that doping with Cu 2+ centers into the framework plays an important role in tuning the dimerization of NO 2 molecules in the pore via the formation of specific host-guest interactions., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Separation of the C 8 aromatic isomers, xylenes (PX, MX, and OX) and ethylbenzene (EB), is important to the petrochemical industry. Whereas physisorptive separation is an energy-efficient alternative to current processes, such as distillation, physisorbents do not generally exhibit strong C 8 selectivity. Herein, we report the mixed-linker square lattice ( sql ) coordination network [Zn 2 (sba) 2 (bis)] n · m DMF ( sql-4,5-Zn , H 2 sba or 4 = 4,4'-sulfonyldibenzoic acid, bis or 5 = trans-4,4'-bis(1-imidazolyl)stilbene) and its C 8 sorption properties. sql-4,5-Zn was found to exhibit high uptake capacity for liquid C 8 aromatics (∼20.2 wt %), and to the best of our knowledge, it is the first sorbent to exhibit selectivity for PX, EB, and MX over OX for binary, ternary, and quaternary mixtures from gas chromatography. Single-crystal structures of narrow-pore, intermediate-pore, and large-pore phases provided insight into the phase transformations, which were enabled by flexibility of the linker ligands and changes in the square grid geometry and interlayer distances. This work adds to the library of two-dimensional coordination networks that exhibit high uptake, thanks to clay-like expansion, and strong selectivity, thanks to shape-selective binding sites, for C 8 isomers., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Deuterium labelling of organic compounds is an important process in chemistry. We report the first example of photocatalytic dehalogenative deuteration of both arylhalides and alkylhalides (40 substrates) over a metal-organic framework, MFM-300(Cr), using CD 3 CN as the deuterium source at room temperature. MFM-300(Cr) catalyses high deuterium incorporation and shows excellent tolerance to various functional groups. Synchrotron X-ray powder diffraction reveals the activation of halogenated substrates via confined binding within MFM-300(Cr). In situ electron paramagnetic resonance spectroscopy confirms the formation of carbon-based radicals as intermediates and reveals the reaction pathway. This protocol removes the use of precious-metal catalysts from state-of-the-art processes based upon direct hydrogen isotope exchange and shows high photocatalytic stability, thus enabling multiple catalytic cycles., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Metal-organic framework (MOF) materials are attracting increasing interest in the field of electronics due to their structural diversity, intrinsic porosity, and designable host-guest interactions. Here, we report the dielectric properties of a series of robust materials, MFM-300(M) (M = Al, Sc, Cr, Fe, Ga, In), when exposed to different guest molecules. MFM-300(Fe) exhibits the most notable increase in dielectric constant to 35.3 ± 0.3 at 10 kHz upon adsorption of NH 3 . Structural analysis suggests that the electron delocalization induced by host-guest interactions between NH 3 and the MOF host, as confirmed by neutron powder diffraction studies, leads to structural polarization, resulting in a high dielectric constant for NH 3 @MFM-300(Fe). This is further supported by ligand-to-metal charge-transfer transitions observed by solid-state UV/vis spectroscopy. The high detection sensitivity and stability to NH 3 suggest that MFM-300(Fe) may act as a powerful dielectric-based sensor for NH 3 .

ConspectusMetal-organic frameworks (MOFs) are a class of hybrid porous materials characterized by their periodic assembly using metal ions and organic ligands through coordination bonds. Their high crystallinity, extensive surface area, and adjustable pore sizes make them promising candidates for a wide array of applications. These include gas adsorption and separation, substrate binding, and catalysis, of relevance to tackling pressing global issues such as climate change, energy challenges, and pollution. In comparison to traditional porous materials such as zeolites and activated carbons, the design flexibility of organic ligands in MOFs, coupled with their orderly arrangement with associated metal centers, allows for the precise engineering of uniform pore environments. This unique feature enables a rich variety of interactions between the MOF host and adsorbed gas molecules, which are fundamental to understanding the observed uptake capacity and selectivity for target gas molecules and thus the overall performance of the material.In this Account, a data set for three-dimensional MOFs has been constructed based upon the structural analysis of host-guest interactions using the largest experimental database, the Cambridge Structural Database (CSD). A full screening was performed on structures with guest molecules of H 2 , C 2 H 2 , CO 2 , and SO 2 , and the relationship between the primary binding site, the isosteric heats of adsorption ( Q st ), and the adsorption uptake was extracted and established. We review the methodologies to refine host-guest interactions based primarily on our studies on the host-guest chemistry of MOFs. The methods include ligand functionalization, variation of metal centers, formation of defects, addition of single atom sites, and control of pore size and structure. In situ structural and dynamic investigations using diffraction and spectroscopic techniques are powerful tools to visualize the details of host-guest interactions upon the above modifications, affording key insights into functional performance at a molecular level. Finally, we give an outlook of future research priorities in the study of host-guest chemistry in MOF materials. We hope this Account will encourage the rational development and improvement of future MOF-based sorbents for applications in challenging gas adsorption, separations, and catalysis.

Conversion of methane (CH 4 ) to ethylene (C 2 H 4 ) and/or acetylene (C 2 H 2 ) enables routes to a wide range of products directly from natural gas. However, high reaction temperatures and pressures are often required to activate and convert CH 4 controllably, and separating C 2+ products from unreacted CH 4 can be challenging. Here, we report the direct conversion of CH 4 to C 2 H 4 and C 2 H 2 driven by non-thermal plasma under ambient (25 °C and 1 atm) and flow conditions over a metal-organic framework material, MFM-300(Fe). The selectivity for the formation of C 2 H 4 and C 2 H 2 reaches 96% with a high time yield of 334 μmol g cat -1 h -1 . At a conversion of 10%, the selectivity to C 2+ hydrocarbons and time yield exceed 98% and 2056 μmol g cat -1 h -1 , respectively, representing a new benchmark for conversion of CH 4 . In situ neutron powder diffraction, inelastic neutron scattering and solid-state nuclear magnetic resonance, electron paramagnetic resonance (EPR), and diffuse reflectance infrared Fourier transform spectroscopies, coupled with modeling studies, reveal the crucial role of Fe-O(H)-Fe sites in activating CH 4 and stabilizing reaction intermediates via the formation of an Fe-O(CH 3 )-Fe adduct. In addition, a cascade fixed-bed system has been developed to achieve online separation of C 2 H 4 and C 2 H 2 from unreacted CH 4 for direct use. Integrating the processes of CH 4 activation, conversion, and product separation within one system opens a new avenue for natural gas utility, bridging the gap between fundamental studies and practical applications in this area.

Proton-exchange membrane fuel cells enable the portable utilization of hydrogen (H 2 ) as an energy resource. Current electrolytic materials have limitation, and there is an urgent need to develop new materials showing especially high proton conductivity. Here, we report the ultra-fast proton conduction in a novel metal-organic framework, MFM-808, which adopts an unprecedented topology and a unique structure consisting of two-dimensional layers of {Zr 6 }-clusters. By replacing the bridging formate with sulfate ligands within {Zr 6 }-layers, the modified MFM-808-SO 4 exhibits an exceptional proton conductivity of 0.21 S·cm -1 at 85 °C and 99% relative humidity. Modeling by molecular dynamics confirms that proton transfer is promoted by an efficient two-dimensional conducting network assembled by sulfate-{Zr 6 }-layers. MFM-808-SO 4 also possesses excellent photocatalytic activity for water splitting to produce H 2 , paving a new pathway to achieve a renewable hydrogen-energy cycle.

We report the modulation of reactivity of nitrogen dioxide (NO 2 ) in a charged metal-organic framework (MOF) material, MFM-305-CH 3 in which unbound N-centres are methylated and the cationic charge counter-balanced by Cl - ions in the pores. Uptake of NO 2 into MFM-305-CH 3 leads to reaction between NO 2 and Cl - to give nitrosyl chloride (NOCl) and NO 3 - anions. A high dynamic uptake of 6.58 mmol g -1 at 298 K is observed for MFM-305-CH 3 as measured using a flow of 500 ppm NO 2 in He. In contrast, the analogous neutral material, MFM-305, shows a much lower uptake of 2.38 mmol g -1 . The binding domains and reactivity of adsorbed NO 2 molecules within MFM-305-CH 3 and MFM-305 have been probed using in situ synchrotron X-ray diffraction, inelastic neutron scattering and by electron paramagnetic resonance, high-field solid-state nuclear magnetic resonance and UV/Vis spectroscopies. The design of charged porous sorbents provides a new platform to control the reactivity of corrosive air pollutants., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Grain size is one of the most frequently selected traits during domestication and modern breeding. The continued discovery and characterization of new genes and alleles in controlling grain size are important in safeguarding the food supply for the world's growing population. Previously, a small grain size was observed in a rice restorer line 'Fuhui212', while the underlying genetic factors controlling this trait were unknown. In this study, by combining QTL mapping, variant effect prediction, and complementation experiments, we recovered a novel allele RGA1-FH that explains most of the phenotypic changes. The RGA1-FH allele contains an A-to-T splicing site variant that disrupts the normal function of RGA1. While population analysis suggests extremely strong artificial selection in maintaining a functional allele of RGA1, our study is the first, to the best of our knowledge, to prove that a dysfunctional RGA1 allele can also be beneficial in real agricultural production. Future breeding programs would benefit from paying more attention to the rational utilization of those overlooked 'unfavored' alleles.

The interactions between adsorbed gas molecules within porous metal-organic frameworks are crucial to gas selectivity but remain poorly explored. Here, we report the modulation of packing geometries of CO 2 and C 2 H 2 clusters within the ultramicroporous CUK-1 material as a function of temperature. In-situ synchrotron X-ray diffraction reveals a unique temperature-dependent reversal of CO 2 and C 2 H 2 adsorption affinities on CUK-1, which is validated by gas sorption and dynamic breakthrough experiments, affording high-purity C 2 H 2 (99.95%) from the equimolar mixture of C 2 H 2 /CO 2 via a one-step purification process. At low temperatures (<253 K), CUK-1 preferentially adsorbs CO 2 with both high selectivity (>10) and capacity (170 cm 3 g -1 ) owing to the formation of CO 2 tetramers that simultaneously maximize the guest-guest and host-guest interactions. At room temperature, conventionally selective adsorption of C 2 H 2 is observed. The selectivity reversal, structural robustness, and facile regeneration of CUK-1 suggest its potential for producing high-purity C 2 H 2 by temperature-swing sorption., (© 2023. The Author(s).)

A core feature of covalent organic frameworks (COFs) is crystallinity, but current crystallization processes rely substantially on trial and error, chemical intuition and large-scale screening, which typically require harsh conditions and low levels of supersaturation, hampering the controlled synthesis of single-crystal COFs, particularly on large scales. Here we report a strategy to produce single-crystal imine-linked COFs in aqueous solutions under ambient conditions using amphiphilic amino-acid derivatives with long hydrophobic chains. We propose that these amphiphilic molecules self-assemble into micelles that serve as dynamic barriers to separate monomers in aqueous solution (nodes) and hydrophobic compartments of the micelles (linkers), thereby regulating the polymerization and crystallization processes. Disordered polyimines were obtained in the micelle, which were then converted into crystals in a step-by-step fashion. Five different three-dimensional COFs and a two-dimensional COF were obtained as single crystals on the gram scale, with yields of 92% and above., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Ultramicroporous materials can be highly effective at trace gas separations when they offer a high density of selective binding sites. Herein, we report that sql-NbOFFIVE-bpe-Cu , a new variant of a previously reported ultramicroporous square lattice, sql , topology material, sql-SIFSIX-bpe-Zn , can exist in two polymorphs. These polymorphs, sql-NbOFFIVE-bpe-Cu-AA ( AA ) and sql-NbOFFIVE-bpe-Cu-AB ( AB ), exhibit AAAA and ABAB packing of the sql layers, respectively. Whereas NbOFFIVE-bpe-Cu-AA ( AA ) is isostructural with sql-SIFSIX-bpe-Zn , each exhibiting intrinsic 1D channels, sql-NbOFFIVE-bpe-Cu-AB ( AB ) has two types of channels, the intrinsic channels and extrinsic channels between the sql networks. Gas and temperature induced transformations of the two polymorphs of sql-NbOFFIVE-bpe-Cu were investigated by pure gas sorption, single-crystal X-ray diffraction (SCXRD), variable temperature powder X-ray diffraction (VT-PXRD), and synchrotron PXRD. We observed that the extrinsic pore structure of AB resulted in properties with potential for selective C 3 H 4 /C 3 H 6 separation. Subsequent dynamic gas breakthrough measurements revealed exceptional experimental C 3 H 4 /C 3 H 6 selectivity (270) and a new benchmark for productivity (118 mmol g -1 ) of polymer grade C 3 H 6 (purity > 99.99%) from a 1:99 C 3 H 4 /C 3 H 6 mixture. Structural analysis, gas sorption studies, and gas adsorption kinetics enabled us to determine that a binding "sweet spot" for C 3 H 4 in the extrinsic pores is behind the benchmark separation performance. Density-functional theory (DFT) calculations and Canonical Monte Carlo (CMC) simulations provided further insight into the binding sites of C 3 H 4 and C 3 H 6 molecules within these two hybrid ultramicroporous materials, HUMs. These results highlight, to our knowledge for the first time, how pore engineering through the study of packing polymorphism in layered materials can dramatically change the separation performance of a physisorbent.

Since its first industrial production in 1890s, acetylene has played a vital role in manufacturing a wide spectrum of materials. Although current methods and infrastructures for various segments of acetylene industries are well-established, with emerging functional porous materials that enabled desired selectivity toward target molecules, it is of timely interest to develop new efficient technologies to promote safer acetylene processes with a higher energy efficiency and lower carbon footprint. In this Minireview, we, from the perspective of materials chemistry, review state-of-the-art examples of advanced porous materials, namely metal-organic frameworks and decorated zeolites, that have been applied to the purification and storage of acetylene. We also discuss the challenges on the roadmap of translational research in the development of new solid sorbent-based separation technologies and highlight areas which require future research efforts., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Electrochemcial reduction of CO 2 to multi-carbon (C 2+ ) products is an important but challenging task. Here, we report the control of structural evolution of two porous Cu(ii)-based materials (HKUST-1 and CuMOP, MOP = metal-organic polyhedra) under electrochemical conditions by adsorption of 7,7,8,8-tetracyanoquinodimethane (TNCQ) as an additional electron acceptor. The formation of Cu(i) and Cu(0) species during the structural evolution has been confirmed and analysed by powder X-ray diffraction, and by EPR, Raman, XPS, IR and UV-vis spectroscopies. An electrode decorated with evolved TCNQ@CuMOP shows a selectivity of 68% for C 2+ products with a total current density of 268 mA cm -2 and faradaic efficiency of 37% for electrochemcial reduction of CO 2 in 1 M aqueous KOH electrolyte at -2.27 V vs. RHE (reversible hydrogen electrode). In situ electron paramagnetic resonance spectroscopy reveals the presence of carbon-centred radicals as key reaction intermediates. This study demonstrates the positive impact of additional electron acceptors on the structural evolution of Cu(ii)-based porous materials to promote the electroreduction of CO 2 to C 2+ products., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)

The development of stable sorbent materials to deliver reversible adsorption of ammonia (NH 3 ) is a challenging task. Here, we report the efficient capture and storage of NH 3 in a series of robust microporous aluminium-based metal-organic framework materials, namely MIL-160, CAU-10-H, Al-fum, and MIL-53(Al). In particular, MIL-160 shows high uptakes of NH 3 of 4.8 and 12.8 mmol g -1 at both low and high pressure (0.001 and 1.0 bar, respectively) at 298 K. The combination of in situ neutron powder diffraction, synchrotron infrared micro-spectroscopy and solid-state nuclear magnetic resonance spectroscopy reveals the preferred adsorption domains of NH 3 molecules in MIL-160, with H/D site-exchange between the host and guest and an unusual distortion of the local structure of [AlO 6 ] moieties being observed. Dynamic breakthrough experiments confirm the excellent ability of MIL-160 to capture of NH 3 with a dynamic uptake of 4.2 mmol g -1 at 1000 ppm. The combination of high porosity, pore aperture size and multiple binding sites promotes the significant binding affinity and capacity for NH 3 , which makes it a promising candidate for practical applications., (© 2023. The Author(s).)

The efficient production of ammonia (NH 3 ) from dinitrogen (N 2 ) and water (H 2 O) using renewable energy is an important step on the roadmap to the ammonia economy. The productivity of this conversion hinges on the design and development of new active catalysts. In the wide scope of materials that have been examined as catalysts for the photo- and electro-driven reduction of N 2 to NH 3 , functional metal-organic framework (MOF) catalysts exhibit unique properties and appealing features. By elucidating their structural and spectroscopic properties and linking this to the observed activity of MOF-based catalysts, valuable information can be gathered to inspire new generations of advanced catalysts to produce green NH 3 . NH 3 is also a surrogate for the hydrogen (H 2 ) economy, and the potential application of MOFs for the practical and effective capture, safe storage, and transport of NH 3 is also discussed. This Perspective analyzes the contribution that MOFs can make toward the ammonia economy.

Persistent organic pollutants (POPs) exist widely in the environment and place significant impact on human health by bioaccumulation. Efficient recognition of POPs and their removal are highly challenging tasks because their specific structures interact often very weakly with the capture materials. Herein, a molecular nanocage ( 1 ) is studied as an efficient sensing and sorbent material for POPs, which is demonstrated by a representative and stable perfluorooctane sulfonate (PFOS) substrate containing a hydrophilic sulfonic group and a hydrophobic fluoroalkyl chain. A highly sensitive and unusual turn-on fluorescence response within 10 s and a 97% total removal of PFOS from water in 20 min have been achieved owing to the strong host-guest interactions between 1 and PFOS. The binding constant of 1 to PFOS is 2 orders of magnitude higher than state-of-the-art adsorbents for PFOS and thus represents a new benchmark material for the recognition and removal of PFOS. The host-guest interaction has been elucidated by solid-state NMR spectroscopy and single-crystal X-ray diffraction, which provide key insights at a molecular level for the design of new advanced sensing/sorbent materials for POPs.

Plants are thought to lack an early segregating germline and often retain both asexual and sexual reproduction, both of which may allow somatic mutations to enter the gametes or clonal progeny, and thereby impact plant evolution. It is yet unclear how often these somatic mutations occur during plant development and what proportion is transmitted to their sexual or cloned offspring. Asexual "seedless" propagation has contributed greatly to the breeding in many fruit crops, such as citrus, grapes and bananas. Whether plants in these lineages experience substantial somatic mutation accumulation is unknown. To estimate the somatic mutation accumulation and inheritance among a clonal population of plant, here we assess somatic mutation accumulation in Musa basjoo, a diploid banana wild relative, using 30 whole-genome resequenced samples collected from five structures, including leaves, sheaths, panicle, roots and underground rhizome connecting three clonal individuals. We observed 18.5 high proportion de novo somatic mutations on average between each two adjacent clonal suckers, equivalent to ~ 2.48 × 10 -8 per site per asexual generation, higher than the per site per sexual generation rates (< 1 × 10 -8 ) reported in Arabidopsis and peach. Interestingly, most of these inter-ramet somatic mutations were shared simultaneously in different tissues of the same individual with a high level of variant allele fractions, suggesting that these somatic mutations arise early in ramet development and that each individual may develop only from a few apical stem cells. These results thus suggest substantial mutation accumulation in a wild relative of banana. Our work reveals the significance of somatic mutation in Musa basjoo genetics variations and contribute to the trait improvement breeding of bananas and other asexual clonal crops., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The production of conjugated C4-C5 dienes from biomass can enable the sustainable synthesis of many important polymers and liquid fuels. Here, we report the first example of bimetallic (Nb, Al)-atomically doped mesoporous silica, denoted as AlNb-MCM-41, which affords quantitative conversion of 2-methyltetrahydrofuran (2-MTHF) to pentadienes with a high selectivity of 91 %. The incorporation of Al III and Nb V sites into the framework of AlNb-MCM-41 has effectively tuned the nature and distribution of Lewis and Brønsted acid sites within the structure. Operando X-ray absorption, diffuse reflectance infrared and solid-state NMR spectroscopy collectively reveal the molecular mechanism of the conversion of adsorbed 2-MTHF over AlNb-MCM-41. Specifically, the atomically-dispersed Nb V sites play an important role in binding 2-MTHF to drive the conversion. Overall, this study highlights the potential of hetero-atomic mesoporous solids for the manufacture of renewable materials., Competing Interests: The authors declare no conflict of interest., (© 2022 The Authors. Angewandte Chemie published by Wiley-VCH GmbH.)

The production of conjugated C4-C5 dienes from biomass can enable the sustainable synthesis of many important polymers and liquid fuels. Here, we report the first example of bimetallic (Nb, Al)-atomically doped mesoporous silica, denoted as AlNb-MCM-41, which affords quantitative conversion of 2-methyltetrahydrofuran (2-MTHF) to pentadienes with a high selectivity of 91 %. The incorporation of Al III and Nb V sites into the framework of AlNb-MCM-41 has effectively tuned the nature and distribution of Lewis and Brønsted acid sites within the structure. Operando X-ray absorption, diffuse reflectance infrared and solid-state NMR spectroscopy collectively reveal the molecular mechanism of the conversion of adsorbed 2-MTHF over AlNb-MCM-41. Specifically, the atomically-dispersed Nb V sites play an important role in binding 2-MTHF to drive the conversion. Overall, this study highlights the potential of hetero-atomic mesoporous solids for the manufacture of renewable materials., (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Increasing levels of air pollution are driving the need for the development of new processes that take "waste-to-chemicals". Herein, we report the capture and conversion under ambient conditions of a major air pollutant, NO 2 , using a robust metal-organic framework (MOF) material, Zr-bptc (H 4 bptc = 3,3',5,5'-biphenyltetracarboxylic acid), comprising {Zr 6 (μ 3 -O) 4 (μ 3 -OH) 4 (COO) 12 } clusters linked by 4-connected bptc 4- ligands in an ftw topology. At 298 K, Zr-bptc shows exceptional stability and adsorption of NO 2 at both low (4.9 mmol g -1 at 10 mbar) and high pressures (13.8 mmol g -1 at 1.0 bar), as measured by isotherm experiments. Dynamic breakthrough experiments have confirmed the selective retention of NO 2 by Zr-bptc at low concentrations under both dry and wet conditions. The immobilized NO 2 can be readily transformed into valuable nitro compounds relevant to construction, agrochemical, and pharmaceutical industries. In situ crystallographic and spectroscopic studies reveal strong binding interactions of NO 2 to the {Zr 6 (μ 3 -O) 4 (μ 3 -OH) 4 (COO) 12 } cluster node. This study paves a circular pathway to enable the integration of nitrogen-based air pollutants into the production of fine chemicals.

The development of cost-effective sorbents for direct capture of trace CO 2 (<1 %) from the atmosphere is an important and challenging task. Natural or commercial zeolites are promising sorbents, but their performance in adsorption of trace CO 2 has been poorly explored to date. A systematic study on capture of trace CO 2 by commercial faujasite zeolites reveals that the extra-framework cations play a key role on their performance. Under dry conditions, Ba-X displays high dynamic uptake of 1.79 and 0.69 mmol g -1 at CO 2 concentrations of 10000 and 1000 ppm, respectively, and shows excellent recyclability in the temperature-swing adsorption processes. K-X exhibits perfect moisture resistance, and >95 % dry CO 2 uptake can be preserved under relative humidity of 74 %. In situ solid-state NMR spectroscopy, synchrotron X-ray diffraction and neutron diffraction reveal two binding sites for CO 2 in these zeolites, namely the basic framework oxygen atoms and the divalent alkaline earth metal ions. This study unlocks the potential of low-cost natural zeolites for applications in direct air capture., (© 2022 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

We report reversible high capacity adsorption of SO 2 in robust Zr-based metal-organic framework (MOF) materials. Zr-bptc (H 4 bptc=biphenyl-3,3',5,5'-tetracarboxylic acid) shows a high SO 2 uptake of 6.2 mmol g -1 at 0.1 bar and 298 K, reflecting excellent capture capability and removal of SO 2 at low concentration (2500 ppm). Dynamic breakthrough experiments confirm that the introduction of amine, atomically-dispersed Cu II or heteroatomic sulphur sites into the pores enhance the capture of SO 2 at low concentrations. The captured SO 2 can be converted quantitatively to a pharmaceutical intermediate, aryl N-aminosulfonamide, thus converting waste to chemical values. In situ X-ray diffraction, infrared micro-spectroscopy and inelastic neutron scattering enable the visualisation of the binding domains of adsorbed SO 2 molecules and host-guest binding dynamics in these materials at the atomic level. Refinement of the pore environment plays a critical role in designing efficient sorbent materials., (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Understanding the structural and chemical changes that reactive metal-organic frameworks (MOFs) undergo is crucial for the development of new efficient catalysts for electrochemical reduction of CO 2 . Here, we describe three Bi(iii) materials, MFM-220, MFM-221 and MFM-222, which are constructed from the same ligand (biphenyl-3,3',5,5'-tetracarboxylic acid) but which show distinct porosity with solvent-accessible voids of 49.6%, 33.6% and 0%, respectively. We report the first study of the impact of porosity of MOFs on their evolution as electrocatalysts. A Faradaic efficiency of 90.4% at -1.1 V vs. RHE (reversible hydrogen electrode) is observed for formate production over an electrode decorated with MFM-220-p, formed from MFM-220 on application of an external potential in the presence of 0.1 M KHCO 3 electrolyte. In situ electron paramagnetic resonance spectroscopy confirms the presence of ·COOH radicals as a reaction intermediate, with an observed stable and consistent Faradaic efficiency and current density for production of formate by electrolysis over 5 h. This study emphasises the significant role of porosity of MOFs as they react and evolve during electroreduction of CO 2 to generate value-added chemicals., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)

Natural gas, consisting mainly of methane (CH 4 ), has a relatively low energy density at ambient conditions (~36 kJ l -1 ). Partial oxidation of CH 4 to methanol (CH 3 OH) lifts the energy density to ~17 MJ l -1 and drives the production of numerous chemicals. In nature, this is achieved by methane monooxygenase with di-iron sites, which is extremely challenging to mimic in artificial systems due to the high dissociation energy of the C-H bond in CH 4 (439 kJ mol -1 ) and facile over-oxidation of CH 3 OH to CO and CO 2 . Here we report the direct photo-oxidation of CH 4 over mono-iron hydroxyl sites immobilized within a metal-organic framework, PMOF-RuFe(OH). Under ambient and flow conditions in the presence of H 2 O and O 2 , CH 4 is converted to CH 3 OH with 100% selectivity and a time yield of 8.81 ± 0.34 mmol g cat -1  h -1 (versus 5.05 mmol g cat -1  h -1 for methane monooxygenase). By using operando spectroscopic and modelling techniques, we find that confined mono-iron hydroxyl sites bind CH 4 by forming an [Fe-OH···CH 4 ] intermediate, thus lowering the barrier for C-H bond activation. The confinement of mono-iron hydroxyl sites in a porous matrix demonstrates a strategy for C-H bond activation in CH 4 to drive the direct photosynthesis of CH 3 OH., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)