Effect of Co‐Surfactants on Properties and Bactericidal Activity of Cu2O and Hybrid Cu2O/Ag Particles

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Effect of Co-Surfactants on Properties and Bactericidal Activity of Cu2O and Hybrid Cu2O/Ag Particles

This study focuses on a green synthesis of Cu2O and Cu2O−Ag particles using ascorbic acid (LAA) as a reducing agent in the presence of two surfactants, polyethylene glycol 6000 and sodium dodecyl sulfate. The hybrid materials exhibit strongly antibacterial activity and are potential for the application in the acrylic emulsion coating.


Abstract

Nanomaterials based on metal oxides, especially Cu2O, have received much attention in recent years due to the many unique properties of the surface plasmon resonance they provide. The report presented the co-precipitation method, a simple preparation method to produce Cu2O oxide particles. In addition, to improve the unique antibacterial properties of Cu2O, a proposed method is to attach Ag nanoparticles to the surface of Cu2O particles. The Cu2O and Cu2O−Ag particles were synthesized based on redox reactions using ascorbic acid (LAA) as a reducing agent. Moreover, in this experiment, two surfactants, polyethylene glycol 6000 (PEG 6000) and sodium dodecyl sulfate (SDS), were added during the manufacturing process to create particle samples and particle combinations with better properties than the original sample. Changes in the characteristics and properties of particle samples are determined by many different physical and chemical methods such as ultraviolet-visible spectroscopy (UV-Vis), infrared spectroscopy (IR), noise X-ray radiation (XRD), scanning electron microscope (SEM), dynamic light scattering (DLS), energy dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). Finally, the activity against bacteria, including E. coli and S. aureus, was also tested using the agar well diffusion method to determine the zone of inhibition. The results improved the particle size value, which decreased by half to 200 nm when two additional surfactants, PEG and SDS, were added. In addition, the antibacterial ability has also been shown to increase significantly when the diameter of the bacterial inhibition zone increased significantly, reaching values of 20 mm (Cu2O/Ag/SDS) and 32 mm (Cu2O/Ag/PEG) for the E. coli bacterial strain. The initial test sample was only about 14 mm in size. The S. aureus bacterial strain also had a similar improvement trend after adding Ag to the Cu2O surface with the appearance of two surfactants, SDS and PEG. The inhibition zone diameter values reached the optimal value at 36 mm in the Cu2O/Ag/PEG particle combination sample compared to only the initial 26 mm in the Cu2O particle sample. Finally, the particle samples are added to the acrylic emulsion paint film to evaluate the changes. Positive results were obtained, such as improvement in adhesion (1.22 MPa), relative hardness (240/425), and sand drop resistance (100 L/mil) in the Cu2O/Ag/PEG particle combination sample, which showed the correctness and accuracy of the research.

Electrochemical intercalation of anions into graphite: Fundamental aspects, material synthesis, and application to the cathode of dual‐ion batteries

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Electrochemical intercalation of anions into graphite: Fundamental aspects, material synthesis, and application to the cathode of dual-ion batteries

This article first describes fundamental aspects of the electrochemical intercalation of anions into graphite. Then, the electrochemical preparation of covalent-type graphite intercalation comopouds, especially, graphite oxide and application of graphite as the cathode of dual-ion battery are discussed.


Abstract

In this review, fundamental aspects of the electrochemical intercalation of anions into graphite have been first summarized, and then described the electrochemical preparation of covalent-type GICs and application of graphite as the cathode of dual-ion battery. Electrochemical overoxidation of anion GICs provides graphite oxide and covalent-fluorine GICs, which are key functional materials for various applications including energy storage devices. The reaction conditions to obtain fully oxidized graphite has been mentioned. Concerning the application of graphite for the cathode of dual-ion battery, it stably delivers about 110 mA h g−1 of reversible capacity in usual organic electrolyte solutions. The combination of anion and solvent as well as the concentration of the anions in the electrolyte solutions greatly affect the performance of graphite cathode such as oxidation potential, rate capability, cycling properties, etc. The interfacial phenomenon is also important, and fundamental studies of charge transfer resistance, anion diffusion coefficient, and surface film formation behavior have also been summarized. The use of smaller anions, such as AlCl4 −, Br− can increase the capacity of graphite cathode. Several efforts on the structural modification of graphite and development of electrolyte solutions in which graphite cathode delivers higher capacity were also described.

Computational Design of Phosphotriesterase Improves V‐Agent Degradation Efficiency

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Computational Design of Phosphotriesterase Improves V-Agent Degradation Efficiency

Organophosphates (OPs) are potent neurotoxins whose current remedies are not very effective. Here we design and characterize variants of the enzyme phosphotriesterase, which can degrade OPs. We report mutations improving catalytic efficiency between 2- and 5-fold and confirm folding and stability of the resulting variants. These findings are a step towards improved OP bioscavengers.


Abstract

Organophosphates (OPs) are a class of neurotoxic acetylcholinesterase inhibitors including widely used pesticides as well as nerve agents such as VX and VR. Current treatment of these toxins relies on reactivating acetylcholinesterase, which remains ineffective. Enzymatic scavengers are of interest for their ability to degrade OPs systemically before they reach their target. Here we describe a library of computationally designed variants of phosphotriesterase (PTE), an enzyme that is known to break down OPs. The mutations G208D, F104A, K77A, A80V, H254G, and I274N broadly improve catalytic efficiency of VX and VR hydrolysis without impacting the structure of the enzyme. The mutation I106 A improves catalysis of VR and L271E abolishes activity, likely due to disruptions of PTE's structure. This study elucidates the importance of these residues and contributes to the design of enzymatic OP scavengers with improved efficiency.

Operando DRIFTS Investigations on Surface Intermediates and Effects of Potassium in CO2 Hydrogenation over a K−Fe/YZrOx Catalyst

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Operando DRIFTS Investigations on Surface Intermediates and Effects of Potassium in CO2 Hydrogenation over a K−Fe/YZrOx Catalyst

Operando DRIFTS study of K−Fe/YZrOx catalyst under CO2 Fischer-Tropsch condition has found the formation of bicarbonate, carbonate, formate, formyl and methoxy species on the surface of the catalyst. It could be established, that bicarbonate species are involved in the formation of CO by RWGS reaction, meanwhile other adsorbents could be hydrogenated to hydrocarbons and CH4.


Abstract

A detailed operando DRIFTS study on the CO2 Fischer-Tropsch reaction with K-promoted Fe/YZrOx catalysts was performed to investigate the influence of this modification on the catalytic performance in the formation of lower olefins as well as higher hydrocarbons and to gain insights into mechanistic aspects. Catalytic testing revealed an enhanced formation of olefins and hydrocarbons by adding potassium to the catalysts, while spectroscopic studies revealed various stable adsorbates and intermediates such as monodentate carbonates, bicarbonates, formates, formyl, and methoxy on the surface of the K-promoted Fe/YZrOx catalysts compared to the unpromoted one. Based on gas-feed switching experiments and statistical analysis of literature IR data regarding Fe-containing catalysts, it was found that carbonate species interacting with H2 are transformed to higher hydrocarbons and methane via formate and formyl formation, while bicarbonate species are decomposed accompanied by the formation of CO, which then further reacts to form formate or formyl and finally hydrocarbons.

Mechanistic Pathways for the Dehydrogenation of Alkanes on Pt(111) and Ru(0001) Surfaces

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Mechanistic Pathways for the Dehydrogenation of Alkanes on Pt(111) and Ru(0001) Surfaces

There is a growing awareness of the negative effects of plastic waste on the environment, leading to a shift towards a more sustainable “circular plastic economy.” However, current recycling methods are limited by being primarily mechanical based, hindering the full realization of a truly circular plastics economy. In this paper, we explore a promising catalytic chemical recycling process that can convert polyolefins into olefins, offering new pathways for upcycling and contributing to the goal of a circular plastics economy.


Abstract

The dehydrogenation of alkanes is a critical process to enable olefin upcycling in a circular economy. A suitable selective catalyst is required in order to avoid demanding reaction conditions and ensure the activation of the C−H bond rather than breaking the C−C bond, which is the weaker of the two. Herein, using periodic density functional theory, we have investigated the dehydrogenation of n-pentane (as a model compound) on Pt and Ru surface catalysts. The results show that the first dehydrogenation occurs through the dissociative adsorption of the C−H bond, resulting in pentyl and H intermediates on the metal surfaces. A successive dehydrogenation creates pentene via a hydride di-σ state, leaving the abstracted hydrogen atoms on the metal surfaces. In agreement with recent experiments, Pt and Ru catalysts show a similar reactivity trend: pentane dehydrogenation yields pent-1-ene and pent-2-ene. The simulations reveal that the 1st C−H dissociation is the rate-determining step, whereas the double-bonded alkenes (pent-1-ene and pent-2-ene) are formed due to fast successive dehydrogenation processes. Pt favors the formation of pent-1-ene, whereas Ru favors the formation of pent-2-ene.

Discovery of a Photoaffinity Probe that Captures the Active Conformation of the Cannabinoid CB2 Receptor

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Discovery of a Photoaffinity Probe that Captures the Active Conformation of the Cannabinoid CB2 Receptor

We present a series of bifunctional photoaffinity CB2R selective probes based on the 5-fluoropyridin-2-yl-benzyl-imidazoleidine-2,4-dione derivative LEI-102, with both inverse agonist and partial agonist behaviour in vitro. These photoaffinity probes have improved affinity and potency compared to previously published LEI-121.


Abstract

The cannabinoid receptor type 2 (CB2R) is a G protein-coupled receptor with therapeutic potential for the treatment of inflammatory disorders. Fluorescent probes are desirable to study its receptor localization, expression and occupancy. Previously, we have reported a photoaffinity probe LEI-121 that stabilized the inactive conformation of the CB2R. Here, we report the structure-based design of a novel bifunctional probe that captures the active conformation of the CB2R upon irradiation with light. An alkyne handle was incorporated to visualize the receptor using click-chemistry with fluorophore-azides. These probes may hold promise to study different receptor conformations in relation to their cellular localization and function.

O‐nitrobenzyl Caged Molecule Enables Photo‐controlled Release of Thiabendazole

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O-nitrobenzyl Caged Molecule Enables Photo-controlled Release of Thiabendazole

NP-TBZ is developed by covalently linking o-nitrobenzyl (NP) with thiabendazole (TBZ). Compound NP-TBZ can be controlled to release TBZ in dependent to light, which resulted in controllable in-vivo activity against wheat scab. It is promising for spatiotemporal controlled-release of TBZ in factual applications, posing a theoretical guidance in development of controlled-release pesticides.


Abstract

Pesticides are essential in agricultural development. Controlled-release pesticides have attracted great attentions. Base on a principle of spatiotemporal selectivity, we extended the photoremovable protective group (PRPG) into agrochemical agents to achieve controllable release of active ingredients. Herein, we obtained NP-TBZ by covalently linking o-nitrobenzyl (NP) with thiabendazole (TBZ). Compound NP-TBZ can be controlled to release TBZ in dependent to light. The irradiated and unirradiated NP-TBZ showed significant differences on fungicidal activities both in vitro and in vivo. In addition, the irradiated NP-TBZ displayed similar antifungal activities to the directly-used TBZ, indicating a factual applicability in controllable release of TBZ. Furthermore, we explored the action mode and microcosmic variations by SEM analysis, and demonstrated that the irradiated NP-TBZ retained a same action mode with TBZ against mycelia growth.

Covalent Organic Frameworks as a Versatile Platform for Iron‐Catalyzed sp3 C−H Activation and Cross‐Coupling via Decarboxylative Oxidation

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Covalent Organic Frameworks as a Versatile Platform for Iron-Catalyzed sp3 C−H Activation and Cross-Coupling via Decarboxylative Oxidation

Efficient oxidative cross-coupling of cinnamic acids with toluene using FeCl3 immobilized on COF pore walls, producing 1,3-arylpropene derivatives. Fine-tuning adjustment of heterogeneous catalytic systems to uncover a significant relationship between pore size and the efficiency of the reaction.


Abstract

This work demonstrates the oxidative cross-coupling of cinnamic acids with toluene using FeCl3 immobilized on a covalent organic framework (COF) pore wall, resulting in the synthesis of 1,3-arylpropene derivatives. This iron-based heterogeneous catalytic system affords the desired products in moderate yields ranging from 51 % to 65 %. Investigations using COFs with varying pore sizes indicate that larger pores facilitate the reaction, suggesting a spatial requirement for this transformation within the catalyst. The correlation between pore size and reaction efficiency provides insights into developing tailored catalysts to match the spatial requirements of the transformation. This version emphasizes the novelty of the study and the synthesis of 1,3-arylpropene derivatives. It also clarifies that the iron-based heterogeneous catalytic system is responsible for the reaction. Additionally, it provides a more detailed explanation of the findings regarding pore size and spatial requirements.

Chiral Phenol‐2NO Ligand Cooperation with Achiral Organic Base in the Zn(II)‐Catalyzed Asymmetric Alkylation Reaction of Indoles

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Chiral Phenol-2NO Ligand Cooperation with Achiral Organic Base in the Zn(II)-Catalyzed Asymmetric Alkylation Reaction of Indoles

A new class of rigid-featured chiral tridentate Phenol-2NO ligands, that incorporate the advantages of both the phenol skeleton and pyrroloimidazolone-based N-oxide moiety, was rationally designed and developed. This represented the first activation of phenol-type ligand/metal complex by an achiral organic base as the additive in asymmetric catalysis.


Comprehensive Summary

The privileged C 2-symmetric rigid phenol-type ligand is more attractive but challenging in asymmetric catalysis. Herein, we designed and synthesized a class of rigid-featured chiral tridentate Phenol-2NO ligands, that incorporate the advantages of both the phenol skeleton and pyrroloimidazolone-based N-oxide moiety, from readily available L-prolinamides in operationally simple two steps and up to 44% overall yield. More importantly, using an achiral quinoline derivative as an additive, the newly developed Phenol-2NO ligand could serve as the anioic ligand upon deprotonative activation to coordinate to Zn(II) to form a highly enantioselective catalyst for the asymmetric Michael-type Friedel-Crafts alkylation reaction of indoles with 2,3-dioxopyrrolidines. Excellent yields (up to 90%) and high enantioselectivities (up to 99% ee) are obtained for a wide range of substrates under mild conditions. Experiments and DFT calculations revealed the reaction mechanism and the origins of the enantioselectivity. This also represented the first activation of phenol-type ligand/metal complex by an achiral organic base as the additive in asymmetric catalysis.

Phosphorescence Properties of Boron/Bismuth Hybrid Conjugated Materials

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By introducing main-group elements such as boron and bismuth to π-conjugated systems, it is possible to modify the optical properties of π-conjugated materials through orbital interactions between the orbital on the elements and π/π*-orbitals, and the heavy atom effect. Moreover, bismuth, which is the heaviest stable element, induces a significant heavy atom effect, making organobismuth compounds promising for applications as phosphorescent materials. In this study, we synthesized new room-temperature phosphorescent materials by incorporating bismuth into thiophene units. The phosphorescence properties of these materials, such as emission lifetime and wavelength, could be further controlled by combining tricoordinate boron with the thienylbismuth structures. The synthesized bismuth- and boron-containing thiophene compounds exhibited phosphorescence at room temperature in both solution and solid states. Furthermore, the introduction of boron raised the energy of the triplet state in the π-conjugated system, resulting in a blue shift of the phosphorescence wavelength. The analysis of photoluminescence properties and TD-DFT calculations revealed that the introduction of bismuth enhances phosphorescence properties, whereas the introduction of boron further promotes intersystem crossing.