Metal–Organic Frameworks against Toxic Chemicals

Crystallographic Visualization of Distinct Iodic Aggregations in Isostructural Metal-Organic Frameworks

Precisely determining the location of adsorbed molecules is essential for illuminating the mechanisms underlying molecular confinement within porous metal-organic frameworks (MOFs). Here, we present the pore-filling and reactive adsorption of iodine in ALP-MOF-1 and its isostructural redox-active ALP-MOF-2. The adsorbed iodine molecules (I2) are unaffected by Zn(II) in ALP-MOF-1 and are exclusively confined into an unusual three-dimensional (3D) iodine aggregation due to the 3D cross-linked pore topology and multiple I2-framework interactions. Conversely, in ALP-MOF-2, the adsorbed I2 enables the oxidation of Co(II) to Co(III), which is accompanied by the reduction of I2 to I3- and the formation of I5- and I2 during continuous I2 loading. Identification of distinct iodine adsorption processes in ALP-MOF-1 and -2 motivated tuning of the metal ion composition to adjust the adsorption mechanism. The iodic aggregations in both MOFs are unambiguously confirmed by the combination of single crystal X-ray diffraction and spectroscopic characterization. The presence of multiple adsorption sites facilitate rapid iodine uptake of ∼179 wt % in ALP-MOF-1 and ∼150 wt % in ALP-MOF-2 within ∼5 h, which could be advantageous for applications requiring rapid and energy-efficient iodine capture.

Simultaneous Capture of N2O and CO2 from a N2O/N2/CO2/O2 Mixture with a Ni(II)-Pyrazolecarboxylate Framework

Nitrous oxide (N2O) is a potent greenhouse gas and a major contributor to ozone depletion. Its primary industrial emission source is tail gas from adipic acid production, which typically comprises a mixture of N2O, CO2, N2, and O2. Current technologies for the removal of N2O and CO2 from tail gas are energy-intensive and operationally complex. Herein, for the first time, simultaneous capture of N2O and CO2 from the quaternary mixture is achieved using a Ni(II)-pyrazolecarboxylate framework, BUT-167. This material demonstrated an exceptional adsorption capacity (135.8 cm3 cm-3 at 40 kPa) and a high packing density (790 mg cm-3) for N2O, outperforming reported sorbents. Moreover, BUT-167 also exhibits a remarkable CO2 adsorption capacity (101.5 cm3 cm-3 at 4 kPa), achieving simultaneously high selectivity values of 257.6 for CO2/N2 (4:96, v/v) and 135.7 for N2O/N2 (40/60). Importantly, BUT-167 exhibits robust and outstanding dual-gas removal performance across multiple adsorption-desorption breakthrough cycles under both dry and humid conditions. The strong affinity toward CO2 and N2O could be attributed to multiple hydrogen bonding interactions facilitated by its highly confined channel structure, as confirmed through single-crystal X-ray diffraction analysis.

Respiration Drives Dynamic Metal-Organic Framework for Smart Photoresponse to Volatile Toxic Vapors and Their Photodynamic Sterilization

Using aggregation-induced emission luminous (AIEgens) containing dynamic molecular rotor structures as linkers to construct flexible smart luminescent metal-organic frameworks (MOFs) has become a transformative approach to constructing artificial intelligence color-changing materials. Herein, 4',4″,4'″,4″″-(ethene-1,1,2,2-tetrayl)tetrabiphenyl-4-carboxylic acid (H4TPPE) is selected as a linker, and octahedral Zr6O4(OH)8(H2O)4 cluster are used as secondary building unit (SBU) to construct the first smart luminescent MOF (Zr-TPE-MOF) that can be driven by CH2Cl2 or CH3COOH vapor for respiration. It is worth noting that Zr-TPE-MOF can absorb trace amounts of CH2Cl2 or CH3COOH vapor into the pores through respiration and shows a blue shift of the emission wavelength up to 479 nm and an increase of emission intensity by nearly three times. In addition, the thermochromic behavior of Zr-TPE-MOF is not obvious in the temperature range of 80-350 K, but it has obvious thermofluorochromics behavior in the temperature range of 350-470 K. Zr-TPE-MOF showed highly sensitive and visualized smart photoresponse to the highly toxic Cr2O7 2-, with a detection limit as low as 7.49 µm. Benefiting from the porous framework structure and organic-inorganic hybrid characteristics of Zr-TPE-MOF, it has excellent ROS generation ability and has excellent application prospects in photodynamic sterilization and rapid degradation of colored dyes.

Metal-organic frameworks for NH3 adsorption and separation

Ammonia (NH3) is not only an air pollutant but also a versatile and favourable chemical with widespread applications in human life. As a key component of nitrogen fertilizers, it plays a crucial role in improving crop yields. Additionally, NH3 serves as a hydrogen carrier and working fluid, contributing to the energy transition process. Given the diverse roles of NH3 and the varying requirements for adsorbents across different application scenarios, the rational design and selection of adsorbent materials are paramount. Metal-organic frameworks (MOFs) have emerged as promising adsorbent candidates due to their highly tunable structure and functionality, which can precisely match the characteristics required for NH3 adsorbents in multiple application scenarios. This review provides a comprehensive evaluation of NH3 adsorbents and delves into the stability characterization of MOFs under NH3 atmospheres and the underlying adsorption/degradation mechanisms. Additionally, we discuss the existing methods used to probe the host-guest interactions between MOFs and NH3. Finally, this study systematically summarizes the latest advancements of MOFs as NH3 adsorbents and classifies them according to the different requirements imposed by the varying roles of NH3. This review provides theoretical support for the design of more efficient NH3 adsorbents in the future.

Enhanced biochemical sensing using metallic nanoclusters integrated with metal-organic frameworks (NCs@MOFs): a comprehensive review

In biochemical sensing, substantial progress has been achieved in the design, development, and application of metallic nanoclusters (NCs) and metal-organic frameworks (MOFs) as distinct entities. Integration of these two nanostructured materials is a promising strategy to form innovative composites with improved properties. Some improvements include (i) supporting platform to minimize the aggregation of NCs and enhance the emission efficiency; (ii) dual-emitting NCs@MOFs from the fluorescent/non-fluorescent MOFs and/or fluorescent NCs; and (iii) stability enhancement. These improvements increase the sensitivity, signal-to-noise ratio, and color tonality, lower the limit of detection, and improve other analytical figures of merits. In this review, we outline the preparation methods of NCs@MOF composites with the improvements offered by them in the field of biochemical analysis. Analytical applications in different fields, such as bioanalysis, environmental monitoring and food safety, are presented. Finally, we address the challenges that remain in the development and application of these composites, such as ensuring stability, enhancing the fluorescence intensity, and improving selectivity and scalability. Furthermore, perspectives on future research directions in this rapidly evolving field are offered.

Ammonia removal from simulated fish farms by metal organic framework ingrained by egg shell and fish bones

The current work focuses on the efficient removal of ammonia by calcium-based metal organic framework. Whereas, for the first time, Ca based metal organic framework was synthesized using either fish bones (FB) or eggshell (ES) as biogenic wastes to act as calcium precursors for synthesis of Ca-BDC, abbreviated as Ca-BDC(FB) & Ca-BDC(ES), respectively, to be sequentially applicable for removal of ammonia. The collected data revealed that; FB showed to be more preferable rather than ES as calcium precursor for preparation of highly efficient Ca-BDC. The obtained Ca-BDC (ES) and Ca-BDC (FB) were shown with orthorhombic crystals, while smaller crystal size was observed in case of Ca-BDC (FB) which is reflected in larger surface area (721.38 m2/g) and in turn higher absorptivity for more efficient removal of ammonia. The adsorption of ammonia followed the pseudo-second ordered reaction and Langmuir isotherm, also R2 values of second ordered and Langmuir models were estimated to be 0.98 & 0.99 for Ca-BDC (ES) & Ca-BDC (FB), respectively. The evaluated maximum adsorption capacities (Qm) onto ES & Ca-BDC (ES) were 86.99 mg/g and 308.16 mg/g, respectively. The maximum capacities of ammonia onto FB & Ca-BDC (FB) were 184.28 mg/g and 616.11 mg/g, respectively. Whereas, Ca-BDC (FB) (721.38 m2/g) was shown with significantly wider surface area by factor of 1.3 compared to Ca-BDC (ES) (563.16 m2/g). Overall, the study provides a promising trend for in designing MOFs with appropriate central metals for capturing of NH3.

Ammonia Hydration in a Cu(II)-Pyrazolate Framework for Efficient Trace Capture

Ammonia (NH3) emissions from industrial and agricultural activities pose severe environmental and health issues. Trace NH3 capture typically relies on chemisorption at Lewis acid sites or physisorption on porous adsorbents but usually suffers from irreversible binding, energy-intensive regeneration, and structural degradation. In this work, for the first time, we demonstrate a new hydration pathway as a promising solution. In a Cu(II)-pyrazolate framework, BUT-64(H2O), the bridging water molecules between adjacent Cu(II) ions serve as Brønsted acid sites to hydrate ammonia, achieving a remarkable NH3 packing density of 0.27 g cm-3 at 0.1 kPa and an adsorption capacity of 1.51 mmol g-1 for 1000 ppm NH3 under 80% relative humidity, among the leading adsorbents. The reversible hydration mechanism combines enhanced NH3 affinity with facile regeneration and mitigated moisture co-adsorption, overcoming the inherent trade-off. The remarkable alkaline stability of this material also highlights its potential as an energy-efficient sorbent for trace NH3 capture.

Reactive Polymers of Intrinsic Microporous Aerogels for Rapid Mustard Gas Detoxification

Polymers of intrinsic microporosity (PIMs) have broad application prospects in the detoxification of chemical warfare agents (CWAs) due to their unique pore structure, good tunable reactivity, and solution processability. However, its pore structure is relatively homogeneous, resulting in high resistance to mass transfer. Here, inspired by fractal structure in nature, a structure engineering strategy is proposed to develop 3D reactive nanofibrous aerogels featuring hierarchical porous structures to minimize mass transfer resistance. These aerogels are fabricated with amidoxime-modified PIM-1 (AO-PIM-1) nanofibers serving as building units and flexible SiO2 nanofibers acting as reinforcement. The macro/mesopores of amidoxime-modified PIM-1 nanofibrous aerogels (APAs) originating from freeze-shaping and electrospinning provide interconnected channels for the diffusion of CWAs, and the intrinsic micropores of AO-PIM-1 can effectively trap and anchor adsorbate molecules. In addition, the reactivity of the APAs can be activated by chlorine bleaching. This process forms an N-chlorine structure, which effectively oxidizes the adsorbed CWAs simulant 2-chloroethyl ethyl sulfide (CEES) by APAs, converting them into non-toxic products. The resulting aerogels have the properties of ultralight weight (8 mg cm-3), reversible compression strain of 60%, and repeatable sulfur mustard decontamination (half-life of 1.27 min). These characteristics indicate significant potential for the use in protective materials against vesicant CWAs.

Conductivity of a series of (4,8)-connected lanthanide metal-organic frameworks with [Ln4O5] clusters and high selectivity for visual sensing of nitrophenol compounds

A series of lanthanide (Ln) metal-organic frameworks, namely [Nd4(Hdtztp)2O(OH)4(H2O)4]·5(H2O)·DMF (Nd4), [Sm4(Hdtztp)2O(OH)4(H2O)4]·5(H2O)·DMF (Sm4), [Tb4(Hdtztp)2O(OH)4(H2O)2(DMF)2] (Tb4), and [Er4(Hdtztp)2O(OH)4(H2O)2(DMF)2] (Er4), were synthesized by using 2,5-bis-(2H-tetrazol-5-yl)-terephthalic acid (H4dtztp) and lanthanide nitrate as raw materials under solvothermal conditions. X-ray single crystal diffraction reveals that the Ln4 compounds crystallize in the orthorhombic Pmmn space group. In these structures, four Ln ions are interconnected through four μ-3 OH and one μ-2 O bridge to form a [Ln4O5] cubane, which is surrounded by eight ligands to form 8-connected building units. These 8-connected building units are linked to 4-connected Hdtztp3- forming the 4,8-connected three-dimensional (3D) frameworks of Ln4. The phase and purity of Ln4 polycrystalline samples were confirmed by elemental analysis, thermogravimetric analysis (TG) and powder X-ray diffraction (PXRD). The conductivity test proves the existence of π-π stacking electron transfer pathways between tetrazolium and aromatic carbon rings in the crystal, where the conductivity of Nd4 with the largest atomic radius is one order of magnitude higher than that of Er4 with the smallest atomic radius. Due to the excellent fluorescence performance and water stability, Tb4 can be used as a fluorescent probe for nitro compounds, and its detection limit of p-nitrophenol (4-NP) is 38.5 nM.

Synergistic Aggregation-Induced Emissive Linkers in Metal-Organic Frameworks for Ultrasensitive and Quantitative Visual Sensing

Luminescent metal-organic frameworks (MOFs) represent an emerging class of materials for visual analyte detection. In this study, we present a strategy that integrates two synergistic aggregation-induced emissive (AIE) linkers into a MOF, significantly enhancing sensing sensitivity, selectivity, and quantification capabilities for practical applications. The dual AIE linkers simultaneously optimize porosity and amplify emission intensity. The tailored pore structure precisely matches the molecular dimensions of the pesticide 2,6-dichloro-4-nitroaniline (DCN), while Förster resonance energy transfer between the linkers achieves an exceptional fluorescence quantum yield of 92.6%. This design enables ultrasensitive DCN detection in water, with an unprecedented detection limit at the ppb level, along with superior selectivity, rapid response time, high quantification accuracy, recyclability, and strong resistance to interference. A comprehensive investigation using UV-vis, fluorescence, transient absorption, X-ray photoelectron, and Raman spectroscopies, supported by theoretical calculations, attributes the efficient fluorescence quenching to photoinduced energy transfer. Additionally, we demonstrate instant, naked-eye detection of DCN residues on fruit surfaces and contaminated soil by applying MOF solutions and illuminating under UV light. Quantitative analysis of DCN residues on fruits was further achieved using computer vision and a custom script, providing a practical, on-site method for rapid and precise detection of pesticide residues.

Activating the Gate-Opening of a Metal-Organic Framework and Maximizing Its Adsorption Capacity

Metal-organic frameworks (MOFs) are well-known porous materials owing to their useful adsorption properties; however, some MOFs have limited adsorption capabilities, which can significantly undermine their success as porous materials. Therefore, maximizing their porosity is critical for unlocking their full potential and expanding their practical utilization, such as gas storage, separation, and removal. In this study, flexible MOFs with defined defects were synthesized using a ligand-mixing strategy to improve their porosity and maximize their adsorption capacities. Specifically, we employed a combination of two organic linkers, 4,4'-biphenyldicarboxylic acid (H2BPDC) and 1,4-benzenedicarboxylic acid (H2BDC), in various ratios, to fabricate flexible In-MIL-53D hybrids containing controllable defects within the structure due to the incorporation of the short linker (H2BDC) compared to the original linker (H2BPDC). These structural defects in the In-MIL-53D hybrids activated their gate-openings and enhanced gas adsorption capacities for N2 and CO2. Moreover, the gate-opened activated hybrids exhibited excellent adsorption capacity for the harmful chemical warfare agent simulant, 2-chloroethyl ethyl sulfide (CEES). However, excessive incorporation of defects disrupted the framework's integrity, compromising its stability and increasing the risk of collapse. Therefore, achieving an optimal level of defect incorporation is essential to balance structural stability with enhanced functionality. Among the hybrids, the sample with approximately 39% incorporation of the short linker exhibited up to an 11-fold increase in adsorption capacity for CO2 at 1 P/P0. In addition, this hybrid demonstrated up to 5-fold higher CEES adsorption capacity compared to the pristine In-MIL-53D, highlighting its potential for advanced utilization in relevant fields.

Advancing Metal-Organic Framework-Based Composites for Effective Chemical Warfare Agent Detoxification under Real-World Conditions

Threats from toxic chemical warfare agents (CWAs) persist due to war and terrorist attacks, endangering both human beings and the environment. Metal-organic frameworks (MOFs), which feature ordered pore structures and excellent tunability at both metal/metal cluster nodes and organic linkers, are regarded as the best candidates to directly remove CWAs and their simulants via both physical adsorption and chemically catalyzed hydrolysis or oxidization. MOFs have attracted significant attention in the last two decades that has resulted from the rapid development of MOF-based materials in both fundamental research and real-world applications. In this review, the authors focus on the recent advancements in designing and constructing functional MOF-based materials toward CWAs detoxification and discuss how to bridge the gap between fundamental science and real-world applications. With detailed summaries from different points of view, this review provides insights into design rules for developing next-generation MOF-based materials for protection from both organophosphorus and organosulfur CWAs to mitigate potential threats from CWAs used in wars and terrorism attacks.

Metal-Organic Frameworks (MOFs): Multifunctional Platforms for Environmental Sustainability

Metal-Organic Frameworks (MOFs) have emerged as versatile materials bridging inorganic and organic chemistry to address critical environmental challenges. Composed of metal nodes and organic linkers, these crystalline structures offer unique properties such as high surface area, tunable pore sizes, and structural diversity. Recent advancements in MOFs synthesis, particularly innovative approaches like mechanochemical, microwave-assisted, and ultrasonic synthesis, have significantly enhanced sustainability by utilizing non-toxic solvents, renewable feedstocks, and energy-efficient processes, offering promising solutions to reduce environmental impact. This review highlights these novel methods and their contributions to improving MOFs functionality for applications in environmental remediation, gas capture, and energy storage. We examine the potential of MOFs in catalysis for pollutant degradation, water purification, and hazardous waste removal, as well as their role in next-generation energy storage technologies, such as supercapacitors, batteries, and hydrogen production. Furthermore, we address challenges including scalability, stability, and long-term performance, underscoring the need for continued innovation in synthesis techniques to enable large-scale MOFs applications. Overall, MOFs hold transformative potential as multifunctional materials, and advancements in synthesis and sustainability are critical for their successful integration into practical environmental and energy solutions.

Development of a Multiparticulate Metal-Organic Framework/Textile Fiber Swatch

The versatility of metal-organic frameworks (MOFs) has led to groundbreaking applications in a wide variety of fields, especially in the areas of energy, environment, and sustainability. For example, MOFs can be designed for high uptake of toxic gases and pollutants, such as CO2, NH3, and SO2, but designing a single MOF that shows tangible uptake for all of these gases is challenging due to the differences in the chemical and physical properties of these molecules. To this end, integrating multiple MOFs onto textile fibers and crafting various structures have emerged as pivotal developments, enhancing framework durability and usability. MOF composites prepared on readily available textile fibers offer the flexibility essential for critical applications, including heterogeneous catalysis, chemical sensing, toxic gas adsorption, and drug delivery, while preserving the unique characteristics of MOFs. This study introduces a scalable and adaptable method for seamlessly embedding multiple high-performing MOFs onto a single textile fiber using a dip-coating method. We explored the uptake capacity of these multi-MOF composites for CO2, NH3, and SO2 and observed a performance similar to that of traditional powdered materials. Along with harmful gas adsorption, we also have evaluated the permeation and reactivity of these MOF/textile composites toward chemical warfare agents (CWAs) like GD (soman), HD (mustard gas), and VX. In combination, these results demonstrate a fundamental advancement toward establishing a consistent strategy for the hydrolysis of nerve agents in real-world scenarios. This approach can substantially increase the protection toward CWAs and enhance the effectiveness of protective equipment such as fabrics for protective garments. This dip-coating method for the integration of multiple MOFs on a single textile fiber unlocks a wealth of possibilities and paves the way for future innovations in the deployment of MOF-based composites.

Dual-MOF-Layered Films via Solution Shearing Approach: A Versatile Platform for Tunable Chemiresistive Sensors

Metal-organic frameworks (MOFs) are ideal for gas sensing due to their high porosity and chemical diversity. However, their low electrical conductivity has traditionally limited their application in chemiresistive-type sensors. The recent development of electrically conductive MOFs (cMOFs) has addressed this limitation. However, directly designing cMOFs with specific sensing properties remains challenging due to the limited understanding of their structure-property relationships. At this stage, the synergistic integration of cMOFs with conventional insulating MOFs has emerged as a viable solution, enabling diverse gas interactions and the rational design of sensing properties. Despite this potential, exploration of the diverse roles of MOFs in such composites remains underutilized. Herein, we develop a series of MOF-on-cMOF sensors and demonstrate their tunable sensing properties. A two-step solution-shearing-based film fabrication method enables facile integration of cMOFs with a wide range of conventional MOFs in layered structures. On cMOF thin film as a primary sensing layer, secondary MOF layers with different pore structures and adsorption properties were strategically selected and deposited. These layered film sensors exhibited tunable sensing properties, including enhanced sensitivity, selectivity, response speed, and recovery for analytes such as NH3, H2S, and NO2. These improvements cannot be achieved solely through the conventional role of MOFs as sieving layers. Furthermore, computational analyses elucidated the structure-property relationships underlying these improvements, offering key insights into the rational design of MOF-based gas sensors.

Continuous and Large-Scale Preparation of Hierarchical Porous HKUST-1 via the "Nanofusion" Mechanism Using Liquid-Assisted Mechanosynthesis

Hierarchical porous metal-organic frameworks (HP-MOFs) have attracted considerable attention because of their hierarchical pores, which can address the slow mass transfer and less exposure of active sites in pristine microporous MOFs. Although several preparation methods have been developed to date, a large-scale technique for the synthesis of HP-MOFs is still lacking. In this study, we report a novel method for the large-scale synthesis of HP-HKUST-1 based on liquid-assisted spiral gas-solid two-phase flow (LA-S-GSF). This method ingeniously uses a nebulizer to promote the rapid synthesis of nano-HKUST-1 by introducing trace amounts of water during the S-GSF reaction. During the washing and drying process, these nanoparticles were fully fused to form nanocrystalline aggregates, resulting in a hierarchical porous structure with a large number of micropores, mesopores, and macropores. The pore size distribution can be regulated by changing the drying temperature to obtain HP products with combinations of micropores and mesopores, micropores and macropores, and the formation mechanism of the HP structure was also explored. This method required only 11 min of reaction time to obtain 25.2 g of HP-HKUST-1 in 96% yield, with a corresponding space-time yield (STY) of 6.9 × 104 kg m-3 day-1.

Functional crystalline porous framework materials based on supramolecular macrocycles

Crystalline porous framework materials like metal-organic frameworks (MOFs) and covalent-organic frameworks (COFs) possess periodic extended structures, high porosity, tunability and designability, making them good candidates for sensing, catalysis, gas adsorption, separation, etc. Despite their many advantages, there are still problems affecting their applicability. For example, most of them lack specific recognition sites for guest uptake. Supramolecular macrocycles are typical hosts for guest uptake in solution. Macrocycle-based crystalline porous framework materials, in which macrocycles are incorporated into framework materials, are growing into an emerging area as they combine reticular chemistry and supramolecular chemistry. Organic building blocks which incorporate macrocycles endow the framework materials with guest recognition sites in the solid state through supramolecular interactions. Distinct from solution-state molecular recognition, the complexation in the solid state is ordered and structurally achievable. This allows for determination of the mechanism of molecular recognition through noncovalent interactions while that of the traditional recognition in solution is ambiguous. Furthermore, crystalline porous framework materials in the solid state are well-defined and recyclable, and can realize what is impossible in solution. In this review, we summarize the progress of the incorporation of macrocycles into functional crystalline porous frameworks (i.e., MOFs and COFs) for their solid state applications such as molecular recognition, chiral separation and catalysis. We focus on the design and synthesis of organic building blocks with macrocycles, and then illustrate the applications of framework materials with macrocycles. Finally, we propose the future directions of macrocycle-based framework materials as reliable carriers for specific molecular recognition, as well as guiding the crystalline porous frameworks with their chemistry, applications and commercialization.

A Hydrolytically Stable Metal-Organic Framework for Simultaneous Desulfurization and Dehydration of Wet Flue Gas

Metal-organic frameworks (MOFs) have great prospects as adsorbents for industrial gas purification, but often suffer from issues of water stability and competitive water adsorption. Herein, we present a hydrolytically stable MOF that could selectively capture and recover trace SO2 from flue gas, and exhibits remarkable recyclability in the breakthrough experiments under wet flue-gas conditions, due to its excellent resistance to the corrosion of SO2 and the water-derived capillary forces. More strikingly, its SO2 capture efficiency is barely influenced by the increasing humidity, even if the pore filling with water is reached. Mechanistic studies demonstrate that the delicate pore structure with diverse pore dimensions and chemistry leads to different adsorption kinetics and thermodynamics as well as segregated adsorption domains of SO2 and H2O. Significantly, this non-competitive adsorption mechanism enables simultaneous desulfurization and dehydration by a single adsorbent, opening an avenue toward cost-effective and simplified processing flowcharts for flue gas purification.

Efficient and Visual Detention of Ammonia and TNP Vapors by a Sustainable Highly Luminescent 1D Zn(II) Coordination Polymer

To realize the aim of easy and accurate detection of ammonia and picric acid (PA) in both aqueous and vapor phases based on function-oriented investigation principles, in the present study, we include a luminescent performance with recognition performance, taking into account the application conditions. Zn(II) ions with luminescence qualities and an amine-substituted imidazole moiety with selective recognition properties towards picric acid and ammonia are coupled to generate a novel 1D luminous Zn(II) coordination polymer, Zn-CP [{Zn(II)( 2-ABZ)2(2-BDC)}].MeOH]∞, where 2-ABZ and 2-BDC stand for terephthalic acid and protonated 2 aminobenzimidazole, respectively. Tests for luminescence recognition demonstrate that Zn-CP has potent selectivity, and strong sensitivity to ammonia and PA in both media. In both detection processes, the limit of detection (LOD) values are determined to be 40 nm. Spectroscopic and DFT studies reveal that the detection of Trinitrophenol (TNP) primarily involves a synergistic mechanism of Photoinduced Electron Transfer (PET), Fluorescence Resonance Energy Transfer (FRET), and Charge Transfer (CT). In contrast, the detection of ammonia (NH3) vapor is predominantly driven by hydrogen bonding (H-bonding) formation. The constructed 1D luminous Zn-CP is a new material that guides the development of novel luminous sensors in the future.

From Nanozymes to Multi-Purpose Nanomaterials: The Potential of Metal-Organic Frameworks for Proteomics Applications

Metal-organic frameworks (MOFs) have the potential to revolutionize the biotechnological and medical landscapes due to their easily tunable crystalline porous structure. Herein, the study presents MOFs' potential impact on proteomics, unveiling the diverse roles MOFs can play to boost it. Although MOFs are excellent catalysts in other scientific disciplines, their role as catalysts in proteomics applications remains largely underexplored, despite protein cleavage being of crucial importance in proteomics protocols. Additionally, the study discusses evolving MOF materials that are tailored for proteomics, showcasing their structural diversity and functional advantages compared to other types of materials used for similar applications. MOFs can be developed to seamlessly integrate into proteomics workflows due to their tunable features, contributing to protein separation, peptide enrichment, and ionization for mass spectrometry. This review is meant as a guide to help bridge the gap between material scientists, engineers, and MOF chemists and on the other side researchers in biology or bioinformatics working in proteomics.

Magnetic rod-shaped Mn-based MOF as a multi-functional and recyclable platform for dual-mode ratiometric-based nitrite detection

The development is shown of rod-shaped manganese-based metal-organic frameworks (Mn-MOFs) as hot- and cold-adapted oxidase-like nanozymes, with strong magnetic properties. These Mn-MOFs enable highly sensitive detection of nitrite ions, utilizing both convenient colorimetric ratio analysis and a visual instrument-free-based approach compatible with smartphone-based detection. The Mn-MOF showed multi-functional activity, such as cold/hot-adapted and magnetic oxidase-like activity, catalyzing the oxidation of chromogenic substrates 3,3',5,5'-tetramethylbenzidine (TMB) to blue oxidized TMB (oxTMB). Mn-MOF shows high oxidase activity with Vmax of 1.39 × 10-8 M/s and Km of 0.068 mM for TMB oxidation. Nitrite ions further react with oxTMB to form a yellow color via diazotization resulting in the ratiometric change in absorbance (A652/A461). The color ratio is also quantified through the naked eye and/or smartphone app by analyzing RGB values, providing a rapid, portable, and cost-effective method for on-site detection. When applying Mn-MOF for smartphone-based nitrite detection, it performs excellent detection, with a linear range of 5.0-55.0 µM and a limit of detection of 0.18 µM, superior to most of the oxidase nanozyme-based nitrite sensing platforms. The detection platforms develop sensing probes using a reusable nanozyme that enables highly sensitive and selective detection of nitrite, featuring a broad linear range and a low limit of detection.

Hydrophobic Metal-Formate Composites for Efficient CO2 Capture

Carbon capture, utilization, and sequestration (CCUS) have emerged as pivotal mitigation strategies in addressing climate change induced by greenhouse gas emissions. In this pursuit, our objective is to enhance the efficacy of adsorptive CO2 capture by harnessing state-of-the-art framework sorbents engineered for exceptional CO2 selectivity, high intrinsic stability in the presence of moisture, and facile regeneration. To this end, a series of ultramicroporous mixed aluminum and iron formate framework materials, Fe-ALFs, were synthesized. Furthermore, their moisture stability has been significantly enhanced by passivation with polyvinylidene fluoride (Fe-ALF-PVDF). Gas sorption and breakthrough measurements demonstrate that Fe-ALF-PVDF exhibits outstanding CO2 adsorption capacities (4.6 mmol/g at 298 K) and remarkable CO2/N2 selectivity (387). In addition, it can be economically produced from readily available chemicals and is easy to regenerate. Fe-ALF-PVDF presents an innovative adsorbent material for efficiently capturing CO2 from humid postcombustion flue gases and other moisture-rich gas streams.

Collaboratively removal of phosphate and glyphosate from wastewater by a macroscopic Zr-SA/Ce-UIO-66 adsorbent: Performance, mechanisms and applicability

Dissolved inorganic and organic phosphorus is a major factor in triggering the eutrophication of water bodies. At present, a novel Zr4+ cross-linked sodium alginate encapsulated in Ce-UIO-66 microspheres (Zr-SA/Ce-UIO-66) was prepared and systematically characterized. Its ability for capture of phosphate and glyphosate in their single and binary systems has been investigated comprehensively. Results showed that Zr-SA/Ce-UIO-66 exhibits excellent phosphate adsorption, achieving 92 % removal and a maximum adsorption capacity of 125 mg P/g at 313 K. Diversified mechanisms, including electrostatic attraction, ligand exchange and hydrogen bonding, have cooperatively participated in phosphate removal. Interestingly, in phosphate and glyphosate mixed solutions, the presence of phosphate significantly enhanced the removal of glyphosate for the formation of complexes between phosphate ions and the adsorbent. And that was similar to the presence of glyphosate in phosphate adsorption. Simulated wastewater experiments demonstrated the adsorbent's practical application in water contaminated with both organic phosphorus and glyphosate composites and its potential for recycling and reuse.

Sabatier Optimal of Mn-N4 Single Atom Catalysts for Selective Oxidative Desulfurization

Understanding the relationship of competitive adsorption between reactants is the prerequisite for high activity and selectivity in heterogeneous catalysis, especially the difference between the adsorption energies (Eads) of two reactive intermediates in Langmuir-Hinshelwood (L-H) models. Using oxidative dehydrogenation of hydrogen sulfide (H2S-ODH) as a probe, we develop various metal single atoms on nitrogen-doped carbon (M-NDC) catalysts for controlling Eads-H2S, Eads-O2 and investigating the difference in activity and selectivity. Combining theoretical and experimental results, a Sabatier relationship between the catalytic performance and Eads-O2/Eads-H2S emerges. Mn-NDC as the optimal catalyst shows excellent H2S conversion (>90 %) and sulfur selectivity (>90 %) in a wide range of O2 concentrations over 100 h. Such a high-efficiency performance is attributed to appropriate Eads-H2S and Eads-O2 on Mn-N4 sites, boosting redox cycle between Mn2+ and Mn3+, as well as preferential formation of sulfur. This work provides a fundamental guidance for designing Sabatier optimal catalysts in L-H models.

Comprehensive DFT investigation of small-molecule adsorption on the paradigm M-MOF-74 family of metal-organic frameworks

The capture of toxic chemicals such as NH3, H2S, NO2 and SO2 is essential due to the tremendous threats they pose to human health and the environment. The M-MOF-74 family of metal-organic frameworks has recently gained attention as a promising category of sorbent materials for the capture of toxic chemicals; however, no clear and comprehensive relationships have been established between the capability of the M-MOF-74 to capture all target toxic chemicals and their properties such as the nature and magnetic state of the metal sites. Density-functional theory (DFT) is employed to investigate the binding energy of target molecules on M-MOF-74 with different metals including Mg, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn. The Hubbard U correction is employed to properly treat d electrons of transition metals and its effect explored on the bandgap of M-MOF-74. The magnetic properties of M-MOF-74 are investigated in detail along with their impact on the target molecule adsorption. Our calculations with DFT+U lead to good agreement with available experimentally determined bandgaps and structural properties. M-MOF-74 (M = Ti, V, Cr, Mn, Fe, Co and Cu) exhibit antiferromagnetic behavior, while ferromagnetic behavior prevails for Ni-MOF-74. Not surprisingly, the coordinatively unsaturated metals (M = Mg, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn) are the most likely sites for chemical adsorption of the target adsorbates, and V-MOF-74 and Ti-MOF-74 predicted to be efficient adsorbents for the target molecules, which can be rationalized on the basis of the metal d-band features. The spin configuration of transition metals in M-MOF-74 is found to have a negligible effect on adsorbate binding energies, which suggests that common DFT calculations without careful consideration of the material magnetic states can indeed be used to rapidly screen binding energies of adsorbates on such MOFs, with some notable exceptions; for instance, V-MOF-74 shows potential for magnetic sensing of NO2. This study provides further insight into the role of different unsaturated metals and their magnetic state for the removal of target toxic molecules by metal-organic frameworks.

Leveraging Ligand Desymmetrization to Enrich Structural Diversity of Zirconium Metal-Organic Frameworks for Toxic Chemical Adsorption

The discovery of metal-organic frameworks (MOFs) with novel structures provides significant opportunities for developing porous solids with new properties and enriching the structural diversity of functional materials for various applications. The rational design of building units with specific geometric conformations is essential to direct the construction of MOFs with unique properties. Herein, we leverage a ligand desymmetrization approach to construct a series of new MOFs. A flexible tetratopic carboxylate ligand with a tetrahedral geometry was designed and assembled with a Zr6 cluster, generating four Zr-based MOF structures: NU-2600, NU-2700, NU-2800, and NU-1802, in which the ligand configurations and Zr6 cluster connectivities can be controlled by varying solvents and modulators during synthesis. Except for NU-1802, these represent entirely new topologies. Notably, NU-1802 exhibits structural flexibility, with up to a 74 % reduction in the unit cell volume as confirmed by single-crystal X-ray diffraction studies. Given their microporous structures, we studied the adsorption behaviors of n-hexane and 2-chloroethyl ethyl sulfide to explore the structure-property relationships of these MOFs. Overall, this work highlights ligand desymmetrization as a powerful method to enrich MOF structural diversity and access complex MOFs with non-default topologies suitable for applications such as toxic gas capture.

A Multi-Method Approach to Analyzing MOFs for Chemical Warfare Simulant Capture: Molecular Simulation, Machine Learning, and Molecular Fingerprints

Mustard gas (HD) is a well-known chemical warfare agent, recognized for its extreme toxicity and severe hazards. Metal-organic frameworks (MOFs), with their unique structural properties, show significant potential for HD adsorption applications. Due to the extreme hazards of HD, most experimental studies focus on its simulants, but molecular simulation research on these simulants remains limited. Simulation analyses of simulants can uncover structure-performance relationships and enable experimental validation, optimizing methods, and improving material design and performance predictions. This study integrates molecular simulations, machine learning (ML), and molecular fingerprinting (MFs) to identify MOFs with high adsorption performance for the HD simulant diethyl sulfide (DES), followed by in-depth structural analysis and comparison. First, MOFs are categorized into Top, Middle, and Bottom materials based on their adsorption efficiency. Univariate analysis, machine learning, and molecular fingerprinting are then used to identify and compare the distinguishing features and fingerprints of each category. Univariate analysis helps identify the optimal structural ranges of Top and Bottom materials, providing a reference for initial material screening. Machine learning feature importance analysis, combined with SHAP methods, identifies the key features that most significantly influence model predictions across categories, offering valuable insights for future material design. Molecular fingerprint analysis reveals critical fingerprint combinations, showing that adsorption performance is optimized when features such as metal oxides, nitrogen-containing heterocycles, six-membered rings, and C=C double bonds co-exist. The integrated analysis using HTCS, ML, and MFs provides new perspectives for designing high-performance MOFs and demonstrates significant potential for developing materials for the adsorption of CWAs and their simulants.

Catalytically Active Site Mapping Realized through Energy Transfer Modeling

The demands of a sustainable chemical industry are a driving force for the development of heterogeneous catalytic platforms exhibiting facile catalyst recovery, recycling, and resilience to diverse reaction conditions. Homogeneous-to-heterogeneous catalyst transitions can be realized through the integration of efficient homogeneous catalysts within porous matrices. Herein, we offer a versatile approach to understanding how guest distribution and evolution impact the catalytic performance of heterogeneous host-guest catalytic platforms by implementing the resonance energy transfer (RET) concept using fluorescent model systems mimicking the steric constraints of targeted catalysts. Using the RET-based methodology, we mapped condition-dependent guest (re)distribution within a porous support on the example of modular matrices such as metal-organic frameworks (MOFs). Furthermore, we correlate RET results performed on the model systems with the catalytic performance of two MOF-encapsulated catalysts used to promote CO2 hydrogenation and ring-closing metathesis. Guests are incorporated using aperture-opening encapsulation, and catalyst redistribution is not observed under practical reaction conditions, showcasing a pathway to advance catalyst recyclability in the case of host-guest platforms. These studies represent the first generalizable approach for mapping the guest distribution in heterogeneous host-guest catalytic systems, providing a foundation for predicting and tailoring the performance of catalysts integrated into various porous supports.

Toward understanding ammonia capture in two amino-functionalized metal-organic frameworks using in-situ infrared spectroscopy and DFT calculation

Two isostructural, three-dimensional, interpenetrated amino-functionalized Metal-Organic Frameworks (Co-2AIN-MOF and Cd-2AIN-MOF) based on 2-aminoisonicotinic acid (2AIN) were synthesized, structurally characterized and determined. Based on the PXRD analysis, the solvent exchange hardly changed their framework structure, and the samples fully activated by methanol can be achieved and examined by infrared spectroscopy. Due to the presence of the carbonyl group and free amino groups in the pore of the framework, the NH3 uptakes of Co-2AIN-MOF and Cd-2AIN-MOF are 11.70 and 13.81 mmol/g and at 1 bar, respectively. In-situ Infrared spectroscopy and DFT calculations revealed the different adsorption sites and processes between Co-2AIN-MOF and Cd-2AIN-MOF.

Development of the design and synthesis of metal-organic frameworks (MOFs) - from large scale attempts, functional oriented modifications, to artificial intelligence (AI) predictions

Owing to the exceptional porous properties of metal-organic frameworks (MOFs), there has recently been a surge of interest, evidenced by a plethora of research into their design, synthesis, properties, and applications. This expanding research landscape has driven significant advancements in the precise regulation of MOF design and synthesis. Initially dominated by large-scale synthesis approaches, this field has evolved towards more targeted functional modifications. Recently, the integration of computational science, particularly through artificial intelligence predictions, has ushered in a new era of innovation, enabling more precise and efficient MOF design and synthesis methodologies. The objective of this review is to provide readers with an extensive overview of the development process of MOF design and synthesis, and to present visions for future developments.

Titanium nitride sensor for selective NO2 detection

Efficient detection methods are needed to monitor nitrogen dioxide (NO2), a major NOx pollutant from fossil fuel combustion that poses significant threats to both ecology and human health. Current NO2 detection technologies face limitations in stability and selectivity. Here, we present a transition metal nitride sensor that exhibits exceptional selectivity for NO2, demonstrating a sensitivity 30 times greater than that of the strongest interfering gas, NO. The sensor maintains stability over 6 months and does not utilize platinum or other precious metals. This notable performance has been achieved through preparation of highly active titanium nitride (TiNx) nanoparticles with exceptionally large surface area and a high concentration of nitrogen vacancies. By contrast, a commercial sample of TiN shows no gas sensing activity. Such devices are potentially scalable for everyday NO2 detection and demonstrate that robust high-performance gas sensors based on inexpensive metal nitrides without precious metals are leading candidates for environmental monitoring technologies.

Integration of metal-organic frameworks and clay toward functional composite materials

Metal-organic frameworks (MOFs) have become increasingly important as a class of porous crystalline materials because of their diverse applications. At the same time, significant progress has been achieved in the field of MOF-based composite materials toward novel applications based on the synergistic effect of two or more different components. Clay materials have been explored recently in MOF chemistry for the synthesis of MOF-clay composites, which are a new class of functional materials synthesized by a cooperative combination of MOFs with clay. Such composites have evolved only in the recent past with important functions and applications, such as enhanced gas storage and separation, CO2 capture and conversion, catalysis, drug delivery, and water harvesting. Notably, the typical shortcomings of MOFs, such as moisture sensitivity, poor water dispersibility, poor thermal and chemical stability, and poor processability, could be overcome by developing novel MOF-clay composites. This article provides a concise overview of MOF-clay composites and their applications in various fields that will drive the interest of researchers to explore the emerging field of MOF-clay chemistry. In the initial sections, we classify the clays that have been used in MOF chemistry and briefly discuss their structures and chemistry. We also present the advantages of MOF-clay composites and discuss their synthetic methodologies. In the later sections, we classify different MOF-clay composites based on the clay and present some representative examples of such composites that show unique properties and applications. Finally, the development in this field is summarized, and the future scope of such composites is discussed.

Functionalized Dual/Multiligand Metal-Organic Frameworks for Efficient CO2 Capture under Flue Gas Conditions

Reducing carbon dioxide (CO2) emissions has become increasingly urgent for China, particularly in the industrial sector. Striking a balance between a high CO2 adsorption capacity and long-term stability under practical conditions is crucial for effectively capturing CO2 from flue gas. In this study, a series of functionalized MFM-136 adsorbents were synthesized in which -NO2 and -NH2 groups were grafted onto the kagome lattice of MFM-136. Modifications with -NH2 groups were found to be highly effective for CO2 adsorption, specifically, the CO2 adsorption capacity peaked at 4.35 mmol/g for NH2(0.6)-MFM-136, representing a 55% enhancement more than MFM-136. Concurrently, the CO2/N2 selectivity for NH2(0.6)-MFM-136 was increased 1.57 times. Verification of novel adsorption sites introduced by NH2-H2L4 was conducted by using in situ DRIFT analysis and DFT calculations. It turns out that NH2-H2L4 modification can effectively mitigate the chemical deposition from the impurity gases and significantly improve the adsorbent's hydrophobicity and its tolerance to impurity gases. Remarkably, the reduction in the CO2 absorption capacity for NH2(0.6)-MFM-136 was 34% less than that for MFM-136 after 24 h of exposure to simulated flue gas, making NH2(0.6)-MFM-136 a promising candidate for the potential application of stable and selective CO2 capture under industrial flue gas conditions.

Scalable Melt Polymerization Synthesis of Covalent Organic Framework Films for Room Temperature Low-Concentration SO2 Detection

The development of highly efficient sensors for low-concentration SO2 at room temperature is important for human health and fine chemistry, but it still faces critical challenges. Herein, a scalable olefin-linked covalent organic framework (COF) with an ultramicroporous structure and abundant binding sites is first developed as the SO2 sensing material. The COF can adsorb SO2 of 220 cm3/g at 1 bar and 40 cm3/g at 0.01 bar and 298 K, surpassing all reported COFs. The computational and kinetic adsorption studies deeply unveil the selective adsorption mechanism for low-concentration SO2. Furthermore, the multicomponent gas mixture breakthrough experiments confirm that the COF can specifically capture low-concentration (2000 ppm) SO2. We innovated a melt polymerization technology to fabricate COF films with adjustable substrates and film thicknesses. COF films are directly grown on the interdigital electrodes to prepare the SO2 sensor device, which possesses a low detection limit (86 ppb) and excellent selectivity for SO2 in the presence of 10 other potentially interfering gases. Compared to other reported SO2 sensors, its overall performance is among the top. Prominently, the sensor maintains a stable output signal for more than two months, and recovery can be easily achieved by simply purifying nitrogen at room temperature without heating. This study marks the first use of COFs for SO2 sensing, opening new possibilities for COFs in the detection of low-concentration toxic gases and manufacturing gas sensor devices.

Nitrogen-rich and core-sheath polyamide/polyethyleneimine@Zr-MOF for iodine adsorption and nerve agent simulant degradation

Radioactive nuclides and highly toxic organophosphates are typical deadly threats. Materials with the function of radioactive substances adsorption and organophosphates degradation provide double protection. Herein, dual-functional polyamide (PA)/polyethyleneimine (PEI)@Zr-MOF fiber composite membranes, fabricated by in-situ solvothermal growth of Zr-MOF on PA/PEI electrospun fiber membranes, are designed for protection against two typical model compounds of iodine and dimethyl 4-nitrophenyl phosphate (DMNP). Benefiting from the unique core-sheath structure composed of inner nitrogen-rich fibers and outer porous Zr-MOF, the composite membranes rapidly enrich iodine through abundant active sites of the outer sheath and form complexes with the amine of inner PEI, exhibiting a highly competitive adsorption capacity of 609 mg g-1. Moreover, it can adsorb and degrade DMNP with the synergy of PEI component and Zr-MOF, achieving an 80 % removal of DMNP within 7 min without any additional co-catalyst. This work provides a feasible strategy to fabricate dual-functional materials that protect against radioactive and organophosphorus contaminants.

Portable on-off visual-mode detection using intrinsic fluorescent zinc-based metal-organic framework for detection of diclofenac in pharmaceutical tablets

On-site, robust, and quantitative detection of diclofenac (DCF) is highly significant in bioanalysis and quality control. Fluorescence-based metal-organic frameworks (MOFs) play a pivotal role in biochemical sensing, offering a versatile platform for detecting various biomolecules. However, conventional fluorescent MOF sensors often rely on lanthanide metals, which can pose challenges in terms of cost, accessibility, and environmental impact. Herein, an intrinsic blue fluorescent zinc-based metal-organic framework (FMOF-5) was prepared free from lanthanide metals. Coordination-induced emission as an effective strategy was followed wherein a non-fluorescent ligand is converted to a fluorescent one after insertion in a framework. Conventional fluorometry and smartphone-assisted visual methods were employed for the detection of DCF. The fluorescence emission of the FMOF-5 was effectively quenched upon the addition of the DCF, endowing it an "off" condition, which permits the construction of a calibration curve with a wide linear range of 30-670 µM and a detection limit of about 4.1 µM. Other analytical figures of merit, such as linearity, sensitivity, selectivity, accuracy, and precision were studied and calculated. Furthermore, the proposed sensor was successfully applied to quantify DCF in pharmaceutical tablets with reliable recovery and precision. Importantly, the elimination of lanthanide metals from the fluorescence detection system enhances its practicality and sustainability, making it a promising alternative for DCF detection in pharmaceutical analysis applications.

Nb(V)-containing saponite: A versatile clay for the catalytic degradation of the hazardous organophosphorus pesticide paraoxon under very mild conditions

A synthetic saponite clay containing structural Nb(V) metal centres (NbSAP) was investigated in the abatement of paraoxon-ethyl, an anti-cholinergic organophosphorus pesticide, under mild conditions (neutral pH, room temperature and ambient pressure) in heterogenous phase, without additional basic additives. The material was selected according to its high surface acidity and ease of preparation through a one-step hydrothermal synthesis. The presence of Nb(V) ions played a crucial role in efficiently catalysing the degradation of aggressive chemical substrates. A niobium(V) oxide with very low surface acidity was also tested as a reference material. The study employed a multi-technique approach to monitor the pesticide degradation pathway and by-products formed during abatement experiments in polar non-protic and aqueous solvents. Notably, in water, the concentration of paraoxon-ethyl significantly decreased by 82 % within the first hour of contact with the clay. Additionally, NbSAP demonstrated a good performance after three repeated catalytic cycles and subsequent reactivation.

Computational Analysis of Sarin, Soman, and Their Water Mixtures in NU-1000: Interaction Mechanisms, Distribution Patterns, and Pairing Effects

Due to their extraordinary structural stability under humid conditions, zirconium-based metal-organic frameworks (Zr-MOFs) have been widely investigated for the hydrolytic degradation of nerve agents. That said, mechanisms of hydrolysis in the solid state and the participation of environmental water are not well understood. This work utilizes computational techniques to evaluate the behavior of water and two organophosphorus nerve agents (sarin and soman) in NU-1000, a Zr-MOF with the characteristic attributes for hydrolytic efficiency under humid conditions. Density functional theory (DFT) calculations reveal that soman binds more favorably to NU-1000 active sites than sarin, resulting in different preferential locations of each nerve agent within the framework. The strength of nerve agent binding is also found to vary depending on the site environment, with more favorable binding of both nerve agents occurring in the c-pores of NU-1000 than in the mesopores. Molecular dynamics (MD) simulation results further illustrate that free water molecules in NU-1000 prioritize interactions with nerve agents. Given the variation in their affinity for active site interactions, the introduction of different nerve agents to the framework results in substantial differences in water distribution and behavior. The results give insight into potential variances in the functionality of NU-1000 toward the hydrolysis of each nerve agent. More importantly, they emphasize the significance of considering the role of environmental water in hydrolysis and the possibility of diverse reaction variables based on the type of nerve agent and the properties of the MOF.

Hydrophobic ZIF-8 nanoparticles loaded on chitosan for improved methanol adsorption from fermented wine

Metal-organic frameworks (MOFs) have great potential for the adsorption of minor molecular alcohols in the vapor phase. However, the drawbacks of powdered MOFs, including low recyclability and problematic separation, limit their application in fermented wine. Chitosan (CS) is a low-cost, eco-friendly, moldable matrix used in the food industry. In this study, a novel CS@ZIF-8 adsorbent with excellent microporous surface area was successfully synthesized by incorporating hydrophobic ZIF-8 into CS. The results showed that CS@ZIF-8 beads had a high adsorption affinity for methanol at a Zn2+/2-methylimidazole molar ratio of 1:5. The adsorption mechanism of methanol on CS@ZIF-8 beads was systematically studied by X-ray photoelectron spectroscopy, isotherms, and kinetics. The Langmuir model calculated the maximum adsorption of methanol to 56.8 mg/g. Adsorption kinetics are consistent with pseudo-second-order models. Furthermore, CS@ZIF-8 beads presented excellent recyclability for removing methanol for five consecutive cycles. It could treat 60 bed volumes of Chinese yellow wine in column filtration experiments to make the concentration below 50 mg/L. In summary, the highly efficient CS@ZIF-8 adsorbent has great potential for methanol adsorption from fermented wines. PRACTICAL APPLICATION: Methanol will exhibit adverse symptoms such as weakness and headaches after it is ingested. Therefore, methanol control is an important safety factor in the production of fermented wine. The adsorption method is recognized as a widely used technique due to its high efficiency and selectivity. The CS@ZIF-8 adsorbent synthesized in this paper provides a new idea for methanol removal.

Organophosphorus Hydrolase-like Nanozyme with an Activity-Quenched Aggregation-Induced Emission Effect: A Self-Reporting and Specific Assay of Nerve Agents

Given the promising prospect of aggregation-induced emission luminogens (AIEgens) in fluorescence assays, it is interesting and significant to endow AIEgens with molecular recognition capability (such as enzyme-like activity). Here, an AIE nanomaterial with intrinsic enzyme-like activity (named as "AIEzyme") is designed and synthesized via a facile coordination polymerization of Zr4+ and AIE ligands. AIEzyme possesses enhanced and stable fluorescence in different solvents because of the AIE effect of ligands in the rigid structure of a coordination polymer. On the other hand, the organophosphorus hydrolase (OPH)-mimicking activity of AIEzyme exhibits excellent affinity and specific activity. Interestingly, the OPH-like activity can quench the inherent fluorescence of AIEzyme by the hydrolysate of a typical organophosphorus nerve agent (OPNA), diethyl-4-nitrophenylphosphate. Due to the sensitive activity-induced quenching effect for AIE, the self-reporting fluorescence assay method based on AIEzyme was established, which shows ultrahigh sensitivity, high selectivity, good storage stability, and acceptable reliability for a real sample assay. Moreover, the simultaneous colorimetric method broadens the detection range and the application scenarios. The proposed assay method avoided the interference of O2 during detection because the OPH-like activity does not derive from the generation of ROS. As a bonus, AIEzyme can also be used for the degradation of OPNAs by OPH-like activity, and the process can be self-monitored by AIE quenching. This work would provide a new opportunity for expanding the application of AIEgens and artificial enzymes by endowing AIEgens with enzyme-like activity.

Systematic design and functionalisation of amorphous zirconium metal-organic frameworks

Controlling the structure and functionality of crystalline metal-organic frameworks (MOFs) using molecular building units and post-synthetic functionalisation presents challenges when extending this approach to their amorphous counterparts (aMOFs). Here, we present a new bottom-up approach for synthesising a series of Zr-based aMOFs, which involves linking metal-organic clusters with specific ligands to regulate local connectivity. In addition, we overcome the limitations of post-synthetic modifications in amorphous systems, demonstrating that homogeneous functionalisation is achievable even without regular internal voids. By altering the acidity of the side group, length, and degree of connectivity of the linker, we could control the porosity, proton conductivity, and mechanical properties of the resulting aMOFs.

MIL-101(Cr)/aminoclay nanocomposites for conversion of CO2 into cyclic carbonates

We present the use of an amine functionalized two-dimensional clay i.e., aminoclay (AC), in the chemistry of a three-dimensional metal-organic framework (MOF) i.e., MIL-101(Cr), to prepare MIL-101(Cr)/AC composites, which are exploited as catalysts for efficient conversion of CO2 gas into cyclic carbonates under ambient reaction conditions. Three different MOF nanocomposites, denoted as MIL-101(Cr)/AC-1, MIL-101(Cr)/AC-2, and MIL-101(Cr)/AC-3, were synthesized by an in situ process by adding different amounts of AC to the precursor solutions of the MIL-101(Cr). The composites were characterized by various techniques such as FT-IR, PXRD, FESEM, EDX, TGA, N2 adsorption, as well as CO2 and NH3-TPD measurements. The composites were exploited as heterogeneous catalysts for CO2 cycloaddition reactions with different epoxides and the catalytic activity was investigated at atmospheric pressure under solvent-free conditions. Among all the materials, MIL-101(Cr)/AC-2 shows the best catalytic efficiency under the optimized conditions and exhibits enhanced efficacy compared to various MIL-101(Cr)-based MOF catalysts, which typically need either high temperature and pressure or a longer reaction time or a combination of all the parameters. The present protocol using MIL-101(Cr)/AC-2 as the heterogeneous catalyst gives 99.9% conversion for all the substrates into the products at atmospheric pressure.

Application of machine learning in the study of development, behavior, nerve, and genotoxicity of zebrafish

Machine learning (ML) as a novel model-based approach has been used in studying aquatic toxicology in the environmental field. Zebrafish, as an ideal model organism in aquatic toxicology research, has been widely used to study the toxic effects of various pollutants. However, toxicity testing on organisms may cause significant harm, consume considerable time and resources, and raise ethical concerns. Therefore, ML is used in related research to reduce animal experiments and assist researchers in conducting toxicological research. Although ML techniques have matured in various fields, research on ML-based aquatic toxicology is still in its infancy due to the lack of comprehensive large-scale toxicity databases for environmental pollutants and model organisms. Therefore, to better understand the recent research progress of ML in studying the development, behavior, nerve, and genotoxicity of zebrafish, this review mainly focuses on using ML modeling to assess and predict the toxic effects of zebrafish exposure to different toxic chemicals. Meanwhile, the opportunities and challenges faced by ML in the field of toxicology were analyzed. Finally, suggestions and perspectives were proposed for the toxicity studies of ML on zebrafish in future applications.

Tuning the structure of N-methyldiethanolamine-based deep eutectic solvents for efficient and reversible SO2 capture

Three cheap DESs comprising of N-methyldiethanolamine (MDEA) and imidazole (Im), 1,2,4-triazole, and tetrazole were investigated for capturing SO2 at low concentrations. Surprisingly, with the addition of Im, the SO2 absorption capacity and desorption efficiency were improved. Spectroscopic analysis and quantum chemical calculations confirmed that MDEA-Im effectively and reversibly captured SO2 through the hydrogen bond network and synergistic action between MDEA and Im.

Mechanical Grinding-Induced Intermolecular Charge Transfer for Near-Infrared Photothermal Conversion

In this study, charge-transfer-type compounds comprising synthesized naphthalenediimide derivative (H4NDISA) or its Pb-based coordination polymer (Pb-NDISA) and suitable primary or secondary amine organic molecules were prepared by the solvent-free mechanical grinding method. The coloration phenomenon arising from charge transfer during grinding serves as a discriminative tool for distinguishing various organic guest molecules. The porous structure of Pb-NDISA crystals facilitates the infiltration of guest molecules and contributes to the preservation of the intermolecular charge transfer state. Moreover, the intermolecular charge transfer induced by grinding exhibits remarkable stability in an ambient atmosphere, underscoring the pivotal role of well-ordered molecules in the mechanical grinding procedure. This mechanochromic phenomenon holds promise for the detection and sensing of organic molecules, while the exceptional charge-transfer absorption characteristics offer the potential for efficient near-infrared photothermal conversion.

A Pillar[5]arene-Containing Metal-Organic Framework for Rapid and Highly Capable Adsorption of a Mustard Gas Simulant

Mustard gas causes irreversible damage upon inhalation or contact with the human body. Consequently, the development of adsorbents for effective interception of mustard gas at low concentrations and high flow rates is an urgent necessity. Here we report a stable porous pillar[5]arene-containing metal-organic framework (MOF) based on zirconium (EtP5-Zr-scu), demonstrating that embedding pillar[5]arene units in MOFs can provide specific binding sites for efficient adsorption of a mustard gas simulant, 2-chloroethyl ethyl sulfide (CEES). EtP5-Zr-scu achieves a higher capacity and more rapid adsorption compared to its counterpart without embedded pillar[5]arene units (H4tcpt-Zr-scu) and perethylated pillar[5]arene (EtP5) alone. Single crystal X-ray diffraction and solid-state nuclear magnetic resonance reveal that the enhanced performance of EtP5-Zr-scu is derived from the host-guest complexation between CEES and pillar[5]arene moieties. Moreover, breakthrough experiments confirmed that the interception performance of EtP5-Zr-scu against CEES (800 ppm, 120 mL/min) was significantly improved (566 min/g) compared with H4tcpt-Zr-scu (353 min/g) and EtP5 (0.873 min/g), attributed to the integration of open channels with specific recognition sites. This work marks a significant advancement in the development of macrocycle-incorporated crystalline framework materials with recognition sites for the efficient capture of guest molecules.

Recognition and order of multiple sidechains by metal-organic framework enhances the separation of hexane isomers

Porous materials perform molecular sorting, separation and transformation by interaction between their framework structures and the substrates. Proteins also interact with molecules to effect chemical transformations, but rely on the precise sequence of the amino acid building units along a common polypeptide backbone to maximise their performance. Design strategies that positionally order sidechains over a defined porous framework to diversify the internal surface chemistry would enhance control of substrate processing. Here we show that different sidechains can be ordered over a metal-organic framework through recognition of their distinct chemistries during synthesis. The sidechains are recognised because each one forces the common building unit that defines the backbone of the framework into a different conformation in order to form the extended structure. The resulting sidechain ordering affords hexane isomer separation performance superior to that of the same framework decorated only with sidechains of a single kind. The separated molecules adopt distinct arrangements within the resulting modified pore geometry, reflecting their strongly differentiated environments precisely created by the ordered sidechains. The development of frameworks that recognize and order multiple sidechain functionality by conformational control offers tailoring of the internal surfaces within families of porous materials to direct interactions at the molecular level.

Efficient Capture and Low Energy Release of NH3 by Azophenol Decorated Photoresponsive Covalent Organic Frameworks

In NH3 capture technologies, the desorption process is usually driven by high temperature and low pressure (such as 150-200 °C under vacuum), which accounts for intensive energy consumption and CO2 emission. Developing light responsive adsorbent is promising in this regard but remains a great challenge. Here, we for the first time designed and synthesized a light responsive azophenol-containing covalent organic framework (COF), COF-HNU38, to address this challenge. We found that at 25 °C and 1.0 bar, the cis -COF exhibited a NH3 uptake capacity of 7.7 mmol g-1 and a NH3/N2 selectivity of 158. In the adsorbed NH3, about 29.0 % could be removed by vis-light irradiated cis-trans isomerization at 25 °C, and the remaining NH3 might be released at 25 °C under vacuum. Almost no decrease in adsorption capacity was observed after eight adsorption-desorption cycles. As such, an efficient NH3 capture and low energy release strategy was established thanks to the multiple hydrogen bond interactions (which are strong in total but weak in individuals) between NH3 and the smart COF, as well as the increased polarity and number of hydrogen bond sites after the trans-cis isomerization.