Catalytic Detoxification Research Articles

Engineering the defects of UiO-66 MOF for an improved catalytic detoxification of CWA simulant: methyl paraoxon.

Exigency in search of an ideal candidate for an effective detoxification of chemical warfare agents is still continuing. Zirconium-based Metal-organic Framework (MOF) UiO-66 has shown a significant detoxification of such toxic chemicals owing to its tunable physio-chemical properties and profuse catalytic sites. In this context, a series of UiO-66 MOFs synthesized by tuning the acidity constant (pK a) and concentration of the modulator, synthesis temperature and water molecules was tested for their detoxification efficiency against the simulant 'methyl-paraoxon' at room temperature. Amongst, HCl modulated UiO-66 across the considered synthesis temperature have shown competent catalytic performance in virtue of defects generation within its structure. In addition, the role of catalytic features of UiO-66 obtained by tailoring its defects in enhancing the degradation efficiency has been systematically investigated. The detoxification efficiency of 98.5% with a half-life time of 0.23 min has confirmed the effectiveness of engineered defects in enhancing the catalytic activity of UiO-66 in detoxifying the identified simulant.

Self-Healing Conjugated Microporous Polyanilines for Effective and Continuous Catalytic Detoxification of 4-Nitrophenol to 4-Aminophenol.

Detoxification of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with high efficiency and dynamic performance is challenging for a polymeric catalyst. Herein, a series of conjugated microporous polyanilines (CMPAs), capable of efficiently catalytically reducing 4-NP, were synthesized based on the Buchwald-Hartwig cross-coupling reaction mechanism. By adjusting the types of linkers and the molar ratios of linker to core, CMPAs with different Brunauer-Emmett-Teller (BET) specific surface areas and reduction degrees were obtained and used as the catalysts in reducing 4-NP. The ultrahigh catalytic reduction efficiency (K = 141.32 s-1 g-1, kapp = 0.00353 s-1) was achieved when using CMPA-3-0.7 as the catalyst (prepared with 4,4'-diaminodiphenylamine as the linker and a 0.7:1 molar ratio of linker to core). The catalytic reduction performance exhibited a strong correlation with the reduction degree and BET specific surface area of CMPAs. Furthermore, they also exhibit excellent cycling stability and dynamic performance. The coexistence of a microporous structure and high BET specific surface area endowed CMPAs with an increased number of catalytic active centers. The reversible redox transformation of CMPAs in the presence of NaBH4 and air enabled self-healing (the oxidation units in CMPAs were reduced to reduction units by NaBH4, and the newly generated reduction unit in CMPAs was subsequently oxidized to its original state by the O2 in the air), leading to the reduction reaction of 4-NP proceeded continuously and stably. The aforementioned factors resulted in the high efficiency of CMPAs for reducing 4-NP to 4-AP, enhancing the practical application prospects of CMPAs in the detoxification of 4-NP wastewater.

Supramolecular elastomers with high strength and low toxicity are suitable for safety protection

Elastomer with high strength and toughness, temperature resistance and low smoke toxicity have shown great application prospects in the field of safety protection. In order to meet the needs of high strength, high toughness and smoke toxicity safety, a high-strength structural elastomer is formed by introducing the integration of hard skeleton and soft elastomer, that is, two-dimensional black phosphorus with high flame retardant efficiency and bimetallic hydroxide with catalytic detoxification (BP-MA-LDH) as the hard skeleton, based on the special combination of internal hydrogen bonds. High strength supramolecular poly(Urethane) (SPU) elastomer was manufactured by molecular design. The high strength and toughness SPU elastomer also has a tensile strength of 53.77 Ma and a elongation at break of 715.26 %. The addition of 2.0 wt% BP-MA-LDH reduces the heat release rate of SPU by 58.84 % and the smoke production release by 61.54 %. In terms of flue gas toxicity inhibition, Fractional Effective Dose was used to evaluate the flue gas toxicity of elastomer composites, and the release of CO, HCN, oxynitride and other toxic gases were greatly reduced. The synthetic performance of SPU elastomer composites in strengthening and toughening, smoke suppression and toxicity reduction is much better than that reported by peers.

Catalytic detoxification of mitoxantrone by graphitic carbon nitride (g-C3N4) supported Fe/Pd bimetallic nanoparticles

The overuse of antibiotics and antitumor drugs has resulted in more and more extensive pollution of water bodies with organic drugs, causing detrimental ecological effects, which have attracted attention towards effective and sustainable methods for antibiotics and antitumor drug degradation. Here, the hybrid nanomaterial (g-C3N4@Fe/Pd) was synthesized and used to remove a kind of both an antibiotic and antitumor drug named mitoxantrone (MTX) with 92.0% removal efficiency, and the MTX removal capacity is 450 mg/g. After exposing to the hybrid material the MTX aqueous solution changed color from dark blue to lighter progressively, and LC-UV results of residual solutions show that a new peak at 3.0 min (MTX: 13.2 min) after removal by g-C3N4@Fe/Pd appears, with the simultaneous detection of intermediate products indicating that g-C3N4@Fe/Pd indeed degrades MTX. Detailed mass spectrometric analysis suggests that the nuclear mass ratio decreased from 445.2 (M+1H) to 126.0 (M+1H), 169.1 (M+1H), 239.2 (M+1H), 267.3 (M+1H), 285.2 (M+1H), 371.4 (M+1H) and 415.2 (M+1H), and the maximum proportion (5.63%) substance of all degradation products (126.0 (M+1H)) is 40-100 times less toxic than MTX. A mechanism for the removal and degradation of mitoxantrone was proposed. Besides, actual water experiments confirmed that the maximum removal capacity of MTX by g-C3N4@Fe/Pd is up to 492.4 mg/g (0.02 g/L, 10 ppm).

Enhancement of catalytic detoxification of polycyclic aromatic hydrocarbons in fly ash from municipal solid waste incineration via magnetic hydroxyapatite-assisted hydrothermal treatment

The emission of carcinogenic, teratogenic, and mutagenic polycyclic aromatic hydrocarbons (PAHs) during municipal solid waste incineration (MSWI) of fly ash (FA) has attracted significant attention. Hydrothermal treatment (HT) has emerged as a practical approach for degrading PAHs during MSWI of FA by utilizing magnetite (Fe3O4) as a catalyst and hydrogen peroxide (H2O2) as an oxidizing agent. In this study, as an alternative to traditional hydroxyapatite (HAP), eggshell-derived magnetic hydroxyapatite (MHAP) was synthesized and applied in the hydrothermal catalytic degradation of PAHs in MSWI FA in an H2O2 system for the first time. The degradation efficiency of the PAHs is influenced not only by H2O2 but also by the choice of hydroxyapatite. Adding HAP or MHAP during hydrothermal treatment with H2O2 substantially reduced the overall PAH concentration and toxicity equivalent quantity (TEQ), superior to that without H2O2. MHAP demonstrated superior catalytic activity compared to HAP in the presence of H2O2 in the hydrothermal system. The hydrothermal detoxification of the PAHs increased with increasing MHAP dosage. By employing 0.5 mol/L H2O2 as the oxidant and 15 wt% MHAP as the catalyst, a total PAH degradation rate of 88.9 % was achieved, with a remarkable TEQ degradation rate of 98.3 %. Notably, the level of 4–6-ring PAHs, particularly benzo(a) pyrene (BaP) and dibenz(a,h)anthracene (DahA), with a TEQ of 1.0, was significantly reduced (by 69.4 % and 46.0 %, respectively). MHAP remained stable during the hydrothermal catalytic process, whereas H2O2 was effectively activated by MHAP and decomposed to produce strongly oxidizing hydroxyl (•OH) under hydrothermal conditions. •OH produced from the decomposition of H2O2 and metals on the surface of MHAP act as catalytically active centers, efficiently converting high-ring PAHs to low-ring PAHs. These findings provide valuable insights and a technological foundation for PAH detoxification in MSWI FA via hydrothermal catalytic oxidation.

Luminescent Bacteria as Bioindicators in Screening and Selection of Enzymes Detoxifying Various Mycotoxins.

Interest in enzymes capable of neutralizing various mycotoxins is quite high. The methods used for the screening and selection of enzymes that catalyze the detoxification of mycotoxins should be sensitive and fast. However toxic compounds can be generated under the action of such enzymes. Thus, the assessment of the overall reduction in the toxic properties of reaction media towards bioluminescent bacteria seems to be the most reasonable control method allowing a quick search for the effective enzymatic biocatalysts. The influence of a wide range of mycotoxins and glucanases, which hydrolyze toxins with different chemical structures, on the analytical characteristics of luminescent photobacteria as a biosensing element has been studied. Different glucanases (β-glucosidase and endoglucanase) were initially selected for reactions with 10 mycotoxins based on the results of molecular docking which was performed in silico with 20 mycotoxins. Finally, the biorecognizing luminescent cells were used to estimate the residual toxicity of reaction media with mycotoxins after their interaction with enzymes. The notable non-catalytic decrease in toxicity of media containing deoxynivalenol was revealed with luminous cells for both types of tested glucanases, whereas β-glucosidase provided a significant catalytic detoxification of media with aflatoxin B2 and zearalenone at pH 6.0.

Metal-Organic Framework Gels for Adsorption and Catalytic Detoxification of Chemical Warfare Agents: A Review.

Chemical warfare agents (CWAs) have brought great threats to human life and social stability, and it is critical to investigate protective materials. MOF (metal-organic framework) gels are a class with an extended MOF architecture that are mainly formed using metal-ligand coordination as an effective force to drive gelation, and these gels combine the unique characteristics of MOFs and organic gel materials. They have the advantages of a hierarchically porous structure, a large specific surface area, machinable block structures and rich metal active sites, which inherently meet the requirements for adsorption and catalytic detoxification of CWAs. A series of advances have been made in the adsorption and catalytic detoxification of MOF gels as chemical warfare agents; however, overall, they are still in their infancy. This review briefly introduces the latest advances in MOF gels, including pure MOF gels and MOF composite gels, and discusses the application of MOF gels in the adsorption and catalytic detoxification of CWAs. Meanwhile, the influence of microstructures (pore structures, metal active site, etc.) on the detoxification performance of protective materials is also discussed, which is of great significance in the exploration of high-efficiency protective materials. Finally, the review looks ahead to next priorities. Hopefully, this review can inspire more and more researchers to enrich the performance of MOF gels for applications in chemical protection and other purification and detoxification processes.

Biosynthesis of gold nanoparticles by Penicillium rubens and catalytic detoxification of ochratoxin A and organic dye pollutants.

The environmental pollution caused by chemical dyes is a growing concern nowadays. Limitations of traditional methods opened the route for nanotechnology; owing to the versatile properties of nanomaterials, gold nanoparticles (AuNPs) became a potential strategy for different applications. In the present study, biosynthesis of gold nanoparticles (BioAuNPs) was carried out by reacting chloroauric acid (HAuCl4) with cell-free filtrate of Penicillium rubens sp. nov. NCIM 1937. The AuNPs were then characterized by UV-visible spectroscopy, HR-TEM, FTIR, and DLS analysis to further examine their efficacious biosynthesis and morphological properties including size, shape, and stability. The biogenic AuNPs are polydisperse in nature, with a mean size of 14.92 ± 5nm. These AuNPs exhibited promising antimicrobial activity against Escherichia coli NCIM-2065, Bacillus subtilis NCIM-2010, and Penicillium verrucosum MTCC 4935. In vitro quantitative HPLC results revealed that BioAuNPs significantly inhibited the biosynthesis of ochratoxin A (OTA). Microbial fuel cells (MFCs) are intriguing for power generation and wastewater treatment since they can directly transform chemical energy stored in organic matter to electricity by extracellular electron transfer (EET) via membrane proteins. AuNPs also showed excellent potential for dye degradation of organic pollutants, viz., methylene blue (MB), phenol red (PR), bromothymol blue (BTB), Congo red (CR), and 4-nitrophenol (4-NP). All dye removal efficiencies were estimated and fitted to pseudo-first-order processes using kinetic rate constants (Ka).The present study reveals a simple, original, and eco-friendly method for the synthesis of multifunctional biogenic AuNPs that could be effective in OTA detoxification in food products and organic pollutant removal during wastewater treatment for a sustainable environment.

Superparamagnetic Mn[sbnd]Fe alloy composite derived from cross-bindered of chitosan/rice husk waste/iron aluminate spinel hercynite for rapid catalytic detoxification of aflatoxin B1: Structure, performance and synergistic mechanism

The contamination of foodstuffs with aflatoxins B1 (AFB1) as carcinogen/mutagens toxin produced by Aspergillus fungi that are a major threat to the economy, safe food supply, and human health. To, we present a facile wet-impregnation and co-participation strategies for the construction of a novel superparamagnetic MnFe biocomposite (MF@CRHHT), in which dual metal oxides MnFe were anchored in/on agricultural/forestry residues (chitosan/rice husk waste/hercynite hybrid nanoparticles) and applied for rapid AFB1 detoxification by destroying in a non-thermal/microbial way. Structure, and morphology were comprehensively characterized by various spectroscopic analyses. The AFB1 removal in PMS/MF@CRHHT system followed pseudo-first-order kinetics, and exhibited excellent efficiency (99.3 % in 20 min and 83.1 % in 5.0 min) over a broad pH range (5.0–10.0). Importantly, relationship between high efficiency and physical-chemical properties, and mechanistic insight reveals that the synergistic effect could be related to the formation MnFe bond in MF@CRHHT and then mutual electron transfer between them to enhanced electron density and generate reactive oxygen species. An AFB1 decontamination pathway proposed was based on the free radical quenching experiments and analysis of the degradation intermediates. Thus, the MF@CRHHT can be applied as an efficient, cost-effective, recoverable, environment-friendly and highly efficient biomass-based activator for remediate pollution.

Rational Design of a Zr-MOF@Curli-Polyelectrolyte Hybrid Membrane toward Efficient Chemical Protection, Moisture Permeation, and Catalytic Detoxification.

Developing high-performance protective materials is important for soldiers and civilians who are exposed to the atmosphere of highly toxic chemical warfare agents (CWAs). Polyelectrolyte membranes are promising candidates with excellent chemical resistance and moisture permeability, but they cannot efficiently degrade CWAs. Here, we design and prepare a hybrid membrane through in situ growth of catalytically active zirconium-based metal-organic frameworks (Zr-MOFs) on a polyelectrolyte membrane mediated by biofilm-inspired curli nanofibers (CNFs). Superior to the bare polyelectrolyte membrane, the prepared MOF-808@CNF-PQ hybrid membrane exhibits improved rejection of the nerve agent simulant dimethyl methyl phosphonate (DMMP) vapor and permeation of the water vapor by 113 and 45%, respectively. The water/DMMP selectivity of the hybrid membrane reaches 498.6, approximately 13 times that of the commercial polyelectrolyte membrane Nafion 117. In addition, the hybrid membrane possesses appreciable catalytic activity for the hydrolysis of the nerve agent simulant dimethyl 4-nitrophenyl phosphate (DMNP) with a half-life of ∼38 min. Nanomechanical characterization results based on atomic force microscopy (AFM) techniques demonstrate the critical role of CNFs in mediating Zr-MOF nucleation and the dominant effect of electrostatic interactions on self-assembly of CNFs on polyelectrolyte base. It is also confirmed that the Zr-MOF toppings serve as the key components in physically adsorbing and chemically degrading the DMNP molecules through multiple strong intermolecular interactions. Our work offers a rational strategy to develop advanced membranes toward efficient chemical protection, moisture permeation, and catalytic detoxification against CWAs.

Isomeric sp2-C-conjugated porous organic polymer-mediated photo- and sono-catalytic detoxification of sulfur mustard simulant under ambient conditions

Isomeric sp2-C-conjugated porous organic polymer-mediated photo- and sono-catalytic detoxification of sulfur mustard simulant under ambient conditions

Facile synthesis of zero valent sulfur nanoparticles for catalytic detoxification of hexavalent chromium, cytotoxicity against microalgae and ultraviolet protection properties

Facile synthesis of zero valent sulfur nanoparticles for catalytic detoxification of hexavalent chromium, cytotoxicity against microalgae and ultraviolet protection properties

Near-instantaneous catalytic hydrolysis of organophosphorus nerve agents with zirconium-based MOF/hydrogel composites

Zirconium-based metal-organic frameworks (Zr-MOFs) with Lewis-acidic sites are potent catalysts for degrading organophosphorus nerve agents. However, a volatile basic solution must regenerate the Zr-MOF catalysts, challenging its real-world implementation. By crosslinking polyethylene imine with an epoxide in the presence of selected Zr-MOFs, we prepared Zr-MOF/hydrogel composite catalysts for the rapid degradation of organophosphorus chemicals under atmospheric conditions. We developed a series of Zr-MOF hydrogel powder composites varying in Zr-node connectivity, linker functionality, and topology. The MOF-808 hydrogel powder was the highest-performing MOF-based composite for the hydrolysis of organophosphorus nerve-agent simulants. We coated the MOF-808 hydrogel onto a textile, and the composite rapidly detoxified nerve-agent simulants and actual nerve agents. The resulting half-lives are the fastest reaction rates to date among MOF-based composite materials, representing a critical step toward the production of protective gear for the instantaneous detoxification of nerve agents in practical conditions. • An amine-based hydrogel integrated with Zr-MOFs forms active detoxification catalysts • The MOF/hydrogel composites detoxify two organophosphorus nerve-agent simulants • The MOF/hydrogel composites integrated onto fiber detoxify GD and VX under ambient conditions Chemical warfare agents (CWAs) threaten the health and security of the global population, which motivates the development of protective wear that can rapidly detoxify CWAs into less-toxic species. Metal-organic frameworks (MOFs) are hybrid materials offering exceptional porosity and rich structural chemical diversity. The incorporation of Lewis-acidic sites into MOFs, specifically zirconium-based building blocks, forms highly active catalysts for the hydrolysis of organophosphorus nerve agents. However, a regenerating base and a source of water are needed, limiting the practical incorporation of Zr-MOFs in protective gear. To date, the subsequent incorporation of the active MOF onto a fiber composite has resulted in slow kinetics. Herein, we have designed a MOF/hydrogel powder and fibrous composites for the ultrafast solid-state catalytic detoxification of the phosphoester agents under ambient conditions. This scalable methodology is critical for realizing MOF-based protective masks and clothing. The development of heterogeneous catalyst composites that can detoxify organophosphorus chemical nerve agents through hydrolysis reactions is limited by slow kinetics and the need for water, as well as a base to regenerate the catalyst. We report the incorporation of an amine-based hydrogel integrated with Zr-MOFs onto a fibrous composite that results in the ultrafast solid-state catalytic detoxification of the phosphoester nerve agents (GD and VX) and their less-toxic chemical simulants under ambient conditions.

Role of Zr6 Metal Nodes in Zr-Based Metal-Organic Frameworks for Catalytic Detoxification of Pesticides.

Pesticides are chemicals widely used for agricultural industry, despite their negative impact on health and environment. Although various methods have been developed for pesticide degradation to remedy such adverse effects, conventional materials often take hours to days for complete decomposition and are difficult to recycle. Here, we demonstrate the rapid degradation of organophosphate pesticides with a Zr-based metal-organic framework (MOF), showing complete degradation within 15 min. MOFs with different active site structures (Zr node connectivity and geometry) were compared, and a porphyrin-based MOF with six-connected Zr nodes showed remarkable degradation efficiency with half-lives of a few minutes. Such a high efficiency was further confirmed in a simple flow system for several cycles. This study reveals that MOFs can be highly potent heterogeneous catalysts for organophosphate pesticide degradation, suggesting that coordination geometry of the Zr node significantly influences the catalytic activity.

Photo-assisted enhancement performance for rapid detoxification of chemical warfare agent simulants over versatile ZnIn2S4/UiO-66-NH2 nanocomposite catalysts

Constructing versatile materials with self-detoxification properties are highly desired for emergency destruction of chemical warfare agents (CWAs). Herein, we first reported in-situ fabrication of ZnIn2S4/UiO-66-NH2 nanocomposites (ZnInS/UiO) and their application in catalytic detoxification of two CWA simulants. For nerve agent simulant dimethyl 4-nitrophenyl phosphate (DMNP), the optimal ZnInS/UiO-23.9 displayed 5.9 times increase in hydrolysis rate having the turnover frequency (TOF) of 0.0586 s-1 under simulated solar light (SSL), which is superior to the reported UiO-based catalysts. Photo-assisted enhancement in DMNP detoxification was due to photothermal effect of ZnInS and close interfacial contact in ZnInS/UiO heterostructures, facilitating instantaneous heat transfer from ZnInS to UiO catalytic sites. As for mustard gas surrogate 2-chloroethyl ethyl sulfide (CEES), under SSL irradiation for 15 min, ZnInS/UiO-23.9 can eliminate 96.7% of CEES in droplet experiment, being 4.17 and 3.24 times of ZnInS and UiO accordingly. It was ascribed to spatial separation of photoinduced electron-hole pairs and photothermally-assisted charge transfer in ZnInS/UiO composites, improving catalytic activity for CEES detoxification. Besides, the detected products suggested that CEES conversion underwent reductive dechlorination, radical reactions and hydrolysis. This study can be extended to other multifunctional catalysts based on metal-organic frameworks and provides new opportunities for photoassisted enhanced detoxification of CWAs.

CATALYTIC DETOXIFICATION OF AQUEOUS CYANIDE USING COPPER CROWN ELECTROSPUN CHITOSAN NANOFIBER

Owing to the common phenomenon of cyanide toxicity, this study focused on oxidative catalytic detoxification of aqueous cyanide in the presence of copper-crown chitosan nanofiber. To overcome the difficulty in electrospinning chitosan, chitosan-salicylaldehyde was initially synthesized via Schiff base condensation, electrospun, and post neutralised into chitosan nanofiber. The copper-crown nanofiber was prepared using the impregnation method. The nanofiber material was characterized using FT-IR, SEM, TGA and DSC. The observed pseudo first-order rate constant for the catalytic H2O2 oxidation of aqeous cyanide with copper-crown nanofiber as catalyst was found to be 16 times greater than the oxidation with only copper catalyst. In addition, the reaction was found to be dependent on the size of the copper-crown nanofiber, pH, temperature, and H2O2/CN-. The reusability of the copper-crown nanofiber catalyst makes the process economically and potentially viable for commercial application.

Function-Topology Relationship in the Catalytic Hydrolysis of a Chemical Warfare Simulant in Two Zr-MOFs.

Owing to their high surface area, high concentration of active metal sites, and water stability, zirconium(VI)-based metal-organic frameworks (Zr-MOFs) have shown excellent activity in the hydrolysis of organophosphorus nerve agents (OPNs). In this regard, for the first time, two topologically different Zr-MOFs (Zr-fcu-tmuc and Zr-bcu-tmuc, constructed from the same organic and inorganic building blocks; fcu=face-centered cubic, bcu=body-centered cubic) have been rationally chosen to investigate the effect of network topology on the catalytic hydrolysis of the nerve agent simulant, dimethyl 4-nitrophenyl phosphate (DMNP). A remarkable enhancement in the hydrolysis rate of DMNP was observed with Zr-bcu-tmuc, reducing the half-life more than three-fold compared with Zr-fcu-tmuc. Greater accessibility of the active ZrVI sites in the 8-connected bcu net compared with the 12-connected fcu leads to a faster hydrolysis of DMNP on Zr-bcu-tmuc. Interestingly, the higher activity of Zr-bcu-tmuc was also confirmed by its higher fluorescence sensitivity towards DMNP (limit of detection (LOD)=0.557 μm) compared with Zr-fcu-tmuc (LOD=1.09 μm). The results show that controlling the desired topology of Zr-MOFs is a useful strategy for improving their performance in the detection and catalytic detoxification of OPNs.

Reaction Chemistry of the syn-[Mo2O2(μ-S)2(S2)(DMF)3] Complex with Cyanide and Catalytic Thiocyanate Formation.

Removal of cyanide as nontoxic thiocyanate under physiological conditions may serve as a catalytic detoxification route in vivo. Aqueous catalytic reaction conditions were explored where at the conditions employed the reaction proceeded to exhaustion in 1 h. The complex, syn-[Mo2O2(μ-S)2(S2)(DMF)3] 1, participates in a ligand exchange reaction of the dimethylformamide ligands and cyanide. Simultaneous sulfur abstraction reaction from the terminal disulfide group forms thiocyanate and terminal sulfido ligand. Respective reaction rates for the two reactions appear competitive where different products were isolated solely based on change of reaction temperature. The approach to determine the number of cyanide ligands participating in the ligand exchange reaction by varying the stoichiometry and reaction temperature led to identification and isolation of tetranuclear complexes 2 and 5 and dinuclear complexes 3, 4, and 6. A synthesized and fully characterized thiocyanate analog of 6 (7) supports spectroscopic characterization of 6. The tetranuclear anion, [Mo4O4(μ-S)6(CN)4]4-, 2, was crystallized from a reaction at ambient temperature. The dinuclear anion, [Mo2O2(μ-S)2(S)(CN)3]3-, 3, was crystallized from similar reaction conditions at lower temperature. The reaction yield of thiocyanate obtained at pH of 7.4 and at 9.2 as a function of time, for several ratios of cyanide, favors the sulfur abstraction reaction at elevated pH. The sulfur abstraction reaction is the first step in a proposed mechanism of the reaction of cyanide and thiosulfate to form thiocyanate and sulfite by 1.

Ultra-fast catalytic detoxification of organophosphates by nano-zeolitic imidazolate frameworks

Detrimental and injurious impacts of Organophosphates that have had on environment, humans, organisms and the other animals or plants have not been surreptitious to anyone worldwide. Nevertheless, up to now, among many efforts that have been devoted to detoxification of Organophosphates (OPs), catalytic detoxification has been the most applicable, cost-effective, efficacious and safest way to break down these dangerous materials. Herein, the utilization of zeolitic imidazolate frameworks (ZIFs), for the first time, has been reported to deactivate Diazinon as an organophosphate agent demonstrated at room temperature. In the following research, the catalysts were analyzed by PXRD, FT-IR, FE-SEM, BET, CO2 adsorption/desorption and TG. The decontamination processes were followed by 31P NMR, HPLC, and UV–vis to evaluate catalytic efficiency. Interestingly, supreme reusability, durability and potentially stunning catalytic activity represent them as alternate materials for their amazing elimination of OPs compared to the other MOFs.

Structural Characterization of the Covalent Binding of Keap1 and Thiol‐containing Small Molecules

Oxidative stress is involved in a wide range of human diseases such as cancer, diabetes, and Alzheimer’s disease. High levels of reactive oxygen species (ROS) cause oxidative damage to DNA and other molecules vital to cell function, such as membrane lipids and proteins. Kelch‐like ECH‐associated protein 1 (Keap1) is a primary regulator of the body’s natural defense system against oxidative stress. In the absence of oxidative stress, Keap1 forms a homodimer that binds a single molecule of transcription factor nuclear factor‐like 2 (Nrf2), causing Nrf2 ubiquitination and degradation. Oxidative stress causes Keap1 to release Nrf2, allowing it to translocate to the nucleus, bind to Maf protein, and activate the production of antioxidant enzymes by binding to the antioxidant response element (ARE). Blocking the protein‐protein interaction (PPI) between Keap1 and Nrf2 could have great therapeutic value. The antioxidant enzymes upregulated by free Nrf2 provide an efficient, catalytic detoxification of ROS. However, as PPIs frequently take place between large, flat interfaces on the two participating proteins, these interactions can be difficult to block. A previous study by our collaborators at UCSF identified 43 thiol‐containing compounds (monophores) that can be covalently tethered to Keap1 at a cysteine near the protein interface. The goal of this project is to characterize the interaction between Keap1 and the monophores using X‐ray crystallography to obtain structures of the protein‐monophore complexes, or adducts. This structural data will allow us to judge which compounds are suitable for scaffold optimization, a technique in which a larger molecule is built from an initial smaller compound to improve its potency and selectivity. Information about the binding modes of the monophores could also be incorporated into the design of other types of drugs that have proven effective in blocking PPIs, such as macrocycles. To identify adduct crystallization conditions, a DTNB assay, which measures the number of reactive sulfhydryl groups in a protein, was used to screen buffer conditions without dithiothreitol (DTT) present. A high‐throughput version of this assay was developed and utilized, in combination with differential scanning fluorimetry (DSF), to identify stabilizing conditions in which adduct can form. This assay was validated with a monophore known to have a stabilizing effect on Keap1, and a new buffer condition (50 mM EPPS, 50 mM NaCl, pH 8.0) was identified in which adduct crystallization attempts can be made.Support or Funding InformationThis work was supported by the Arnold and Mabel Beckman Foundation.