COF-supported zirconium oxyhydroxide as a versatile heterogeneous catalyst for Knoevenagel condensation and nerve agent hydrolysis.

A composite of catalytic Lewis acidic zirconium oxyhydroxides (8 wt %) and a covalent organic framework (COF) was synthesized. X-ray diffraction and infrared (IR) spectroscopy reveal that COF's structure is preserved after loading with zirconium oxyhydroxides. Electron microscopy confirms a homogeneous distribution of nano- to sub-micron-sized zirconium clusters in the COF. 3D X-ray tomography captures the micron-sized channels connecting the well-dispersed zirconium clusters on the COF. The crystalline ZrOx(OH)y@COF's nanostructure was model-optimized via simulated annealing methods. Using 0.8 mol % of the catalyst yielded a turnover number of 100-120 and a turnover frequency of 160-360 h-1 for Knoevenagel condensation in aqueous medium. Additionally, 2.2 mol % of catalyst catalyzes the hydrolysis of dimethyl nitrophenyl phosphate, a simulant of nerve agent Soman, with a conversion rate of 37% in 180 min. The hydrolytic detoxification of the live agent Soman is also achieved. Our study unveils COF-stabilized ZrOx(OH)y as a new class of zirconium-based Lewis + Bronsted-acid catalysts.

Deleterious and Adaptive Mutations in Plant Germplasm Conserved Ex Situ.

Conserving more than 7 million plant germplasm accessions in 1,750 genebanks worldwide raises the hope of securing the food supply for humanity for future generations. However, there is a genetic cost for such long-term germplasm conservation, which has been largely unaccounted for before. We investigated the extent and variation of deleterious and adaptive mutations in 490 individual plants representing barley, wheat, oat, soybean, maize, rapa, and sunflower collections in a seed genebank using RNA-Seq technology. These collections were found to have a range of deleterious mutations detected from 125 (maize) to 83,695 (oat) with a mean of 13,537 and of the averaged sample-wise mutation burden per deleterious locus from 0.069 to 0.357 with a mean of 0.200. Soybean and sunflower collections showed that accessions acquired earlier had increased mutation burdens. The germplasm with more years of storage in several collections carried more deleterious and fewer adaptive mutations. The samples with more cycles of germplasm regeneration revealed fewer deleterious and more adaptive mutations. These findings are significant for understanding mutational dynamics and genetic cost in conserved germplasm and have implications for long-term germplasm management and conservation.

Toxin-Blocking Textiles: Rapid, Benign, Roll-to-Roll Production of Robust MOF-Fabric Composites for Organophosphate Separation and Hydrolysis.

Current approaches to create zirconium-based metal-organic framework (MOF) fabric composites for catalysis, water purification, wound healing, gas sorption, and other applications often rely on toxic solvents, long reaction/post processing times, and batch methods hindering process scalability. Here, a novel mechanism was reported for rapid UiO-66-NH2 synthesis in common low-boiling-point solvents (water, ethanol, and acetic acid) and revealed acid-base chemistry promoting full linker dissolution and vapor-based crystallization. The mechanism enabled scalable roll-to-roll production of mechanically resilient UiO-66-NH2 fabrics with superior chemical protective capability. Solvent choice and segregated spray delivery of organic linker and metal salt MOF precursor solutions allowed for rapid MOF nucleation on the fiber surface and decreased the energy and time needed for post-processing, producing an activated composite in less than 165 min, far outpacing conventional MOF-fabric synthesis approaches. The MOF-fabric hydrolyzed and blocked permeation of the chemical warfare agent soman, outperforming the protection-standard activated carbon cloth. This work presents both chemical insights into Zr-MOF powder and fabric composite formation by a rapid, industrially relevant approach and demonstrates its practicality and affordability for high-performing personal protective equipment.

Fabrication of Multifunctional Electronic Textiles Using Oxidative Restructuring of Copper into a Cu-Based Metal-Organic Framework.

This paper describes a novel synthetic approach for the conversion of zero-valent copper metal into a conductive two-dimensional layered metal-organic framework (MOF) based on 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) to form Cu3(HHTP)2. This process enables patterning of Cu3(HHTP)2 onto a variety of flexible and porous woven (cotton, silk, nylon, nylon/cotton blend, and polyester) and non-woven (weighing paper and filter paper) substrates with microscale spatial resolution. The method produces conductive textiles with sheet resistances of 0.1-10.1 MΩ/cm2, depending on the substrate, and uniform conformal coatings of MOFs on textile swatches with strong interfacial contact capable of withstanding chemical and physical stresses, such as detergent washes and abrasion. These conductive textiles enable simultaneous detection and detoxification of nitric oxide and hydrogen sulfide, achieving part per million limits of detection in dry and humid conditions. The Cu3(HHTP)2 MOF also demonstrated filtration capabilities of H2S, with uptake capacity up to 4.6 mol/kgMOF. X-ray photoelectron spectroscopy and diffuse reflectance infrared spectroscopy show that the detection of NO and H2S with Cu3(HHTP)2 is accompanied by the transformation of these species to less toxic forms, such as nitrite and/or nitrate and copper sulfide and Sx species, respectively. These results pave the way for using conductive MOFs to construct extremely robust electronic textiles with multifunctional performance characteristics.

Graphene Oxide and Metal-Organic Framework-Based Breathable Barrier Membranes for Toxic Vapors.

Garments protective against chemical warfare agents (CWAs) or accidently released toxic chemicals must block the transport of toxic gases/vapors for a substantial time and allow moisture transport for breathability. These demands are challenging: either the barriers block CWAs effectively but have poor breathability or barriers have excellent breathability but cannot block CWAs well. Existing protective garments employ large amounts of active carbon, making them quite heavy. Metal-organic framework (MOF)-based adsorbents are being investigated as sorbents for CWAs. Breathable laminate of graphene oxide (GO) flakes supported on a porous membrane reduces permeation rates of CWA simulants substantially. We developed a multilayered membrane-based flexible barrier: GO laminate-based membrane over a MOF nanocrystal-filled expanded polytetrafluorethylene (ePTFE) membrane having submicrometer pores. The GO laminate-based layer developed a steady breakthrough concentration level almost 2 orders of magnitude below the usual breakthrough level. This highly reduced level of CWA was blocked by the MOF nanocrystal-filled membrane substrate layer over a highly extended period. We demonstrated the blocking of CWAs, mustard (HD), soman (GD), a sarin simulant [dimethyl methyl phosphonate (DMMP)], and ammonia for an extended period while the moisture transmission rate was substantial. The times for complete blockage of ammonia, HD, GD, and DMMP were 2750 min, 1075 min, 176 min, and 7 days, respectively. This remarkable performance resulted from a very low steady-state penetrant permeation through GO-laminate membrane and substantial penetrant sorption by MOF nanocrystals; furthermore, both layers show high moisture vapor transmission.

Environmentally Benign Biosynthesis of Hierarchical MOF/Bacterial Cellulose Composite Sponge for Nerve Agent Protection.

The fabrication of MOF polymer composite materials enables the practical applications of MOF-based technology, in particular for protective suits and masks. However, traditional production methods typically require organic solvent for processing which leads to environmental pollution, low-loading efficiency, poor accessibility, and loss of functionality due to poor solvent resistance properties. For the first time, we have developed a microbial synthesis strategy to prepare a MOF/bacterial cellulose nanofiber composite sponge. The prepared sponge exhibited a hierarchically porous structure, high MOF loading (up to ≈90 %), good solvent resistance, and high catalytic activity for the liquid- and solid-state hydrolysis of nerve agent simulants. Moreover, the MOF/ bacterial cellulose composite sponge reported here showed a nearly 8-fold enhancement in the protection against an ultra-toxic nerve agent (GD) in permeability studies as compared to a commercialized adsorptive carbon cloth. The results shown here present an essential step toward the practical application of MOF-based protective gear against nerve agents.

Immobilized Regenerable Active Chlorine within a Zirconium-Based MOF Textile Composite to Eliminate Biological and Chemical Threats.

The most recent global health crisis caused by the SARS-CoV-2 outbreak and the alarming use of chemical warfare agents highlight the necessity to produce efficient protective clothing and masks against biohazard and chemical threats. However, the development of a multifunctional protective textile is still behind to supply adequate protection for the public. To tackle this challenge, we designed multifunctional and regenerable N-chlorine based biocidal and detoxifying textiles using a robust zirconium metal-organic framework (MOF), UiO-66-NH2, as a chlorine carrier which can be easily coated on textile fibers. A chlorine bleaching converted the amine groups located on the MOF linker to active N-chlorine structures. The fibrous composite exhibited rapid biocidal activity against both Gram-negative bacteria (E. coli) and Gram-positive bacteria (S. aureus) with up to a 7 log reduction within 5 min for each strain as well as a 5 log reduction of SARS-CoV-2 within 15 min. Moreover, the active chlorine loaded MOF/fiber composite selectively and rapidly degraded sulfur mustard and its chemical simulant 2-chloroethyl ethyl sulfide (CEES) with half-lives less than 3 minutes. The versatile MOF-based fibrous composite designed here has the potential to serve as protective cloth against both biological and chemical threats.

Patterns of Genetic Variation in a Soybean Germplasm Collection as Characterized with Genotyping-by-Sequencing.

Genomic characterization is playing an increasing role in plant germplasm conservation and utilization, as it can provide higher resolution with genome-wide SNP markers than before to identify and analyze genetic variation. A genotyping-by-sequencing technique was applied to genotype 541 soybean accessions conserved at Plant Gene Resources of Canada and 30 soybean cultivars and breeding lines developed by the Ottawa soybean breeding program of Agriculture and Agri-Food Canada. The sequencing generated an average of 952,074 raw sequence reads per sample. SNP calling identified 43,891 SNPs across 20 soybean chromosomes and 69 scaffolds with variable levels of missing values. Based on 19,898 SNPs with up to 50% missing values, three distinct genetic groups were found in the assayed samples. These groups were a mixture of the samples that originated from different countries and the samples of known maturity groups. The samples that originated from Canada were clustered into all three distinct groups, but 30 Ottawa breeding lines fell into two groups only. Based on the average pairwise dissimilarity estimates, 40 samples with the most genetic distinctness were identified from three genetic groups with diverse sample origin and known maturity. Additionally, 40 samples with the highest genetic redundancy were detected and they consisted of different sample origins and maturity groups, largely from one genetic group. Moreover, some genetically duplicated samples were identified, but the overall level of genetic duplication was relatively low in the collection. These findings are useful for soybean germplasm management and utilization.

Battling Chemical Weapons with Zirconium Hydroxide Nanoparticle Sorbent: Impact of Environmental Contaminants on Sarin Sequestration and Decomposition.

The promising reactive sorbent zirconium hydroxide (ZH) was challenged with common environmental contaminants (CO2, SO2, and NO2) to determine the impact on chemical warfare agent decomposition. Several environmental adsorbates rapidly formed on the ZH surface through available hydroxyl species and coordinatively unsaturated zirconium sites. ZH decontamination effectiveness was determined using a suite of instrumentation including in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to monitor sarin (GB) decomposition in real time and at ambient pressure. Surface products were characterized by ex situ X-ray photoelectron spectroscopy (XPS). The adsorption enthalpies, entropies, and bond lengths for environmental contaminants and GB decomposition products were estimated using density functional theory (DFT). Consistent with the XPS and DRIFTS results, DFT simulations predicted the relative stabilities of molecular adsorbates and reaction products in the following order: CO2 < NO2 < GB ≈ SO2. Microbreakthrough capacity measurements on ZH showed a 7-fold increase in the sorption of NO2 vs SO2, which indicates differences in the surface reactivity of these species. GB decomposition was rapid on clean and CO2-dosed ZH and showed reduced decomposition on SO2- and NO2-predosed samples. Despite these findings, the total GB sorption capacity of clean and predosed ZH was consistent across all samples. These data provide insight into the real-world use of ZH as a reactive sorbent for chemical decontamination applications.

Stretchable and Multi-Metal-Organic Framework Fabrics Via High-Yield Rapid Sorption-Vapor Synthesis and Their Application in Chemical Warfare Agent Hydrolysis.

Protocols to create metal-organic framework (MOF)/polymer composites for separation, chemical capture, and catalytic applications currently rely on relatively slow solution-based processing to form single MOF composites. Here, we report a rapid, high-yield sorption-vapor method for direct simultaneous growth of single and multiple MOF materials onto untreated flexible and stretchable polymer fibers and films. The synthesis utilizes favorable reactant absorption into polymers coupled with rapid vapor-driven MOF crystallization to form high surface area (>250 m2/gcomposite) composites, including UiO-66-NH2, HKUST-1, and MOF-525 on spandex, nylon, and other fabrics. The resulting composites are robust and maintain their functionality even after stretching. Stretchable MOF fabrics enable rapid solid-state hydrolysis of the highly toxic chemical warfare agent soman and paraoxon-methyl simulant. We show that this approach can readily be scaled by solution spray-coating of MOF precursors and to large area substrates.

Doubly Protective MOF-Photo-Fabrics: Facile Template-Free Synthesis of PCN-222-Textiles Enables Rapid Hydrolysis, Photo-Hydrolysis and Selective Oxidation of Multiple Chemical Warfare Agents and Simulants.

New materials and chemical knowledge for improved personal protection are among the most pressing needs in the international community. Reported attacks using chemical warfare agents (CWAs,) including organophosphate soman (GD) and thioether mustard gas (HD) are driving research in field-deployable catalytic composites for rapid toxin degradation. In this work, we report simple template-free low temperature synthesis that enables for the first time, a deployable-structured catalytic metal-organic framework/polymer textile composite "MOF-fabric" showing rapid hydrolysis and oxidation of multiple active chemical warfare agents, GD and HD, respectively, and their simulants. Our method yields new zirconium-porphyrin based nano-crystalline PCN-222 MOF-fabrics with adjustable MOF loading and robust mechanical adhesion on low-cost nonwoven polypropylene fibers. Importantly, we describe quantitative kinetic analysis confirming that our MOF-fabrics are as effective as or better than analogous MOF powders for agent degradation, especially for oxidation. Faster oxidation using the MOF-fabrics is ascribed to the composite geometry, where active MOF catalysts are uniformly displayed on the MOF-textile enabling better reactant transport and reactive oxidant generation. Furthermore, we note the discovery of visible photo-activation of GD hydrolysis by a MOF-fabric, which is ascribed to oxidation at the active metal node site, significantly increasing the rate over that observed without illumination. These results provide important new insights into the design of future materials and chemical systems to protect military, first-responders, and civilians upon exposure to complex chemical toxins.

Structural Diversity of Zirconium Metal-Organic Frameworks and Effect on Adsorption of Toxic Chemicals.

While linkers with various conformations pose challenges in the design and prediction of metal-organic framework (MOF) structures, they ultimately provide great opportunities for the discovery of novel structures thereby enriching structural diversity. Tetratopic carboxylate linkers, for example, have been widely used in the formation of Zr-based MOFs due to the ability to target diverse topologies, providing a promising platform to explore their mechanisms of formation. However, it remains a challenge to control the resulting structures when considering the complex assembly of linkers with unpredicted conformations and diverse Zr6 node connectivities. Herein, we systematically explore how solvents and modulators employed during synthesis influence the resulting topologies of Zr-MOFs, choosing H4TCPB-Br2 (1,4-dibromo-2,3,5,6-tetrakis(4-carboxyphenyl)benzene) as a representative tetratopic carboxylate linker. By modulating the reaction conditions, the conformations of the linker and the connectivities of the Zr6 node can be simultaneously tuned, resulting in four types of structures: a new topology (NU-500), she (NU-600), scu (NU-906), and csq (NU-1008). Importantly, we have synthesized the first 5-connected Zr6 node to date with the (4,4,4,5)-connected framework, NU-500. We subsequently performed detailed structural analyses to uncover the relationship between the structures and topologies of these MOFs and demonstrated the crucial role that the flexible linker played to access varied structures by different degrees of linker deformation. Due to a variety of pore structures ranging from micropores to hierarchical micropores and mesopores, the resulting MOFs show drastically different behaviors for the adsorption of n-hexane and dynamic adsorption of 2-chloroethyl ethyl sulfide (CEES) under dry and humid conditions.

Graphene Oxide-Based Membrane as a Protective Barrier against Toxic Vapors and Gases.

Traditional protective garments loaded with activated carbons to remove toxic gases are very bulky. Novel graphene oxide (GO) flake-based composite lamellar membrane structure is being developed as a potential component of a garment for protection against chemical warfare agents (CWAs) represented here by simulants, dimethyl methyl phosphonate (DMMP) (a sarin-simulant), and 2-chloroethyl ethyl sulfide (CEES) (a simulant for sulfur mustard), yet allowing a high-moisture transmission rate. GO flakes of dimensions 300-800 nm, 0.7-1.2 nm thickness and dispersed in an aqueous suspension were formed into a membrane by vacuum filtration on a porous poly(ether sulfone) (PES) or poly(ether ether ketone) (PEEK) support membrane for noncovalent π-π interactions with GO flakes. After physical compression of such a membrane, upright cup tests indicated that it can block toluene for 3-4 days and DMMP for 5 days while exhibiting excellent water vapor permeation. Further, they display very low permeances for small-molecule gases/vapors. The GO flakes underwent cross-linking later with ethylenediamine (EDA) introduced during the vacuum filtration followed by physical compression and heating. With a further spray coating of polyurethane (PU), these membranes could be bent without losing barrier properties vis-à-vis the CWA simulant DMMP for 5 days; a membrane not subjected to bending blocked DMMP for 15 days. For the PEEK-EDA-GO-PU-compressed membranes after bending, the separation factors of H2O over other species for low gas flow rates in the dynamic moisture permeation cell (DMPC) are: αH2O-He is 42.3; αH2O-N2 is 110; and αH2O-ethane is 1800. At higher gas flow rates in the DMPC, the moisture transmission rate goes up considerably due to reduced boundary layer resistances and exceeds the threshold water vapor flux of 2000 g/(m2·day) that defines a breathable fabric. This membrane displayed considerable resistance to permeation by CEES as well. The PES-EDA-GO-PU-compressed membrane shows good mechanical property under tensile strength tests.

A Flexible Interpenetrated Zirconium-Based Metal-Organic Framework with High Affinity toward Ammonia.

Flexible metal-organic frameworks (MOFs) are highly attractive porous crystalline materials presenting structural changes when exposed to external stimuli, the mechanism of which is often difficult to glean, owing to their complex and dynamic nature. Herein, a flexible interpenetrated Zr-MOF, NU-1401, composed of rare 4-connected Zr6 nodes and tetratopic naphthalenediimide (NDI)-based carboxylate linkers, was designed. The intra-framework pore opening deformation and inter-framework motions, when subjected to different solvent molecules, were investigated by single-crystal XRD. The distance and overlap angle between the stacked NDI pairs in the entangled structure could be finely tuned, and the interactions between NDI and solvent molecules led to solvochromism. Furthermore, the presence of electron-deficient NDI units in the linker and acid sites on the node of the interpenetrated porous structure offered high density of adsorption sites for ammonia molecules, resulting in high uptake at low pressures.

High-Throughput Screening of MOFs for Breakdown of V-Series Nerve Agents.

Metal-organic frameworks (MOFs) have shown promise for the catalytic decomposition of chemical weapons. Finding the best materials for the degradation of nerve agents requires the ability to screen a high number of samples and elucidate the key parameters of effective catalysis. In this work, a high-throughput screening (HTS) method has been developed to evaluate MOFs as catalysts, specifically against the V-class of nerve agents. Over 100 MOFs have been tested using the V-class simulant, O,O-diethyl S-phenyl phosphorothioate (DEPPT), revealing good activity for some UiO-66 derivatives. A medium-throughput hydrolysis assay for the nerve agent O-ethyl S-[2-(diisopropylamino)ethyl]methylphosphonothioate (VX) was also performed using six MOFs selected from HTS and was validated by 31P NMR. The results demonstrated that the DEPPT-based assay is a good indicator of V-series agent reactivity and should be considered in addition to the common (4-nitrophenyl)phosphate (DMNP) assay that is used for G-series agents.

Integration of Metal-Organic Frameworks on Protective Layers for Destruction of Nerve Agents under Relevant Conditions.

Metal-organic frameworks (MOFs) are promising candidates for the catalytic hydrolysis of nerve agents and their simulants. Though highly efficient, bulk water and volatile bases are often required for hydrolysis with these MOF catalysts, preventing real-world implementation. Herein we report a generalizable and scalable approach for integrating MOFs and non-volatile polymeric bases onto textile fibers for nerve agent hydrolysis. Notably, the composite material showed similar reactivity under ambient conditions compared to the powder material in aqueous alkaline solution. This represents a critical step toward a unified strategy for nerve agent hydrolysis in practical settings, which can significantly reduce the dimensions of filters and increase the efficiency of protective suits.

Elevated mutation and selection in wild emmer wheat in response to 28 years of global warming.

Global warming has been documented to threaten wild plants with strong selection pressures, but how plant populations respond genetically to the threats remains poorly understood. We characterized the genetic responses of 10 wild emmer wheat (Triticum dicoccoides Koern.; WEW) populations in Israel, sampling them in 1980 and again in 2008, through an exome capture analysis. It was found that these WEW populations were under elevated selection, displayed reduced diversity and temporal divergence, and carried increased mutational burdens forward. However, some populations still showed the ability to acquire beneficial alleles via selection or de novo mutation for future adaptation. Grouping populations with mean annual rainfall and temperature revealed significant differences in most of the 14 genetic estimates in either sampling year or over the 28 y. The patterns of genetic response to rainfall and temperature varied and were complex. In general, temperature groups displayed more temporal differences in genetic response than rainfall groups. The highest temperature group had more deleterious single nucleotide polymorphisms (dSNPs), higher nucleotide diversity, fewer selective sweeps, lower differentiation, and lower mutational burden. The least rainfall group had more dSNPs, higher nucleotide diversity, lower differentiation and higher mutational burden. These characterized genetic responses are significant, allowing not only for better understanding of evolutionary changes in the threatened populations, but also for realistic modeling of plant population adaptability and vulnerability to global warming.

Scalable and Template-Free Aqueous Synthesis of Zirconium-Based Metal-Organic Framework Coating on Textile Fiber.

Organophosphonate-based nerve agents, such as VX, Sarin (GB), and Soman (GD), are among the most toxic chemicals to humankind. Recently, we have shown that Zr-based metal-organic frameworks (Zr-MOFs) can effectively catalyze the hydrolysis of these toxic chemicals for diminishing their toxicity. On the other hand, utilizing these materials in powder form is not practical, and developing scalable and economical processes for integrating these materials onto fibers is crucial for protective gear. Herein, we report a scalable, template-free, and aqueous solution-based synthesis strategy for the production of Zr-MOF-coated textiles. Among all MOF/fiber composites reported to date, the MOF-808/polyester fibers exhibit the highest rates of nerve agent hydrolysis. Moreover, such highly porous fiber composites display significantly higher protection time compared to that of its parent fabric for a mustard gas simulant, 2-chloroethyl ethyl sulfide (CEES). A decreased diffusion rate of toxic chemicals through the MOF layer can provide time needed for the destruction of the harmful species.

Ligand-Directed Reticular Synthesis of Catalytically Active Missing Zirconium-Based Metal-Organic Frameworks.

Zirconium-based metal-organic frameworks (Zr-MOFs) based on edge-transitive nets such as fcu, spn, she, csq, and ftw with diverse potential applications have been widely reported. Zr-MOFs based on the highly connected 6,12-connected alb net, however, remain absent on account of synthetic challenges. Herein we report the ligand-directed reticular syntheses and isoreticular expansion of a series of Zr-MOFs with the edge-transitive alb net from 12-connected hexagonal-prismatic Zr6 nodes and 6-connected trigonal-prismatic linkers, i.e., microporous NU-1600, mesoporous NU-1601, and mesoporous NU-1602. These Zr-MOFs exhibit remarkable activities toward the destruction of a nerve agent (soman) and a nerve agent simulant (DMNP).