Ag System Research Articles

Diffusion coefficients calculations of 110mAg in ZrC at very high temperature using machine-learning interatomic potential

The ternary machine-learning interatomic potential for a Zr–C–Ag system was developed using first-principles calculations, moment tensor potential, and molecular dynamics simulations to calculate the diffusion coefficient of Ag in ZrC. The developed potential was utilized to investigate the vacancy formation energy, Ag substitutional energy, binding energy between Ag and vacancy, Ag interstitial energy, migration energy of Ag to an adjacent C vacancy in ZrC, and thermal expansion of ZrC. The results conformed to previously reported experimental and computational results, thereby validating the accuracy of the developed potential. The diffusion coefficients of Ag in ZrC0.94 and ZrC0.97 in the temperature range of 2800–3200 K were calculated using molecular dynamics simulations with the developed machine-learning interatomic potential. These calculation results can aid the safety analysis of radioactive 110mAg release in nuclear thermal propulsion reactors.

Silver- and gold-catalyzed azide−alkyne cycloaddition by functionalized NHC-based polynuclear catalysts: Computational investigation and mechanistic insights

This study evaluated the catalytic efficiency of Au(I), Ag(I), and Cu(I) complexes in the azide‒alkyne cycloaddition (AAC) reaction through density functional theory (DFT) calculations. Cu(I) complexes exhibit superior catalytic performance, with lower energy barriers (8.8 kcal/mol) and a favorable Gibbs free energy of -0.9 kcal/mol in the key cycloaddition step, significantly outperforming Ag and Au complexes. Structural analysis revealed that shorter M−C bond lengths in the Cu complex contributed to increased stability. Additionally, the copper complex has a more negative Gibbs free energy for the formed metallacycle, indicating a thermodynamically favorable reaction pathway. Noncovalent interaction (NCI) and reduced density gradient (RDG) analyses of the Cu, Ag, and Au systems highlighted distinct interaction patterns influencing the reactivity. Furthermore, electron localization function (ELF) and localized orbital locator (LOL) analyses revealed bonding characteristics in those complexes. This study offers valuable insights into the mechanistic differences among Au(I), Ag(I), and Cu(I) complexes, paving the way for future research on enhancing the catalytic activity of copper, silver and gold complexes through ligand modification.

B-071 Unraveling Histamine Intolerance: Exploring DAO Quantity, Elimination Ratios and Cofactor Influences

Abstract Background Non-allergic reactions to food, often triggered by biogenic amines like histamine, result in symptoms such as headache, rhinitis, respiratory issues, digestive complaints, and eczema. The symptomatic overlap between histamine intolerance (HIT) and allergies may contribute to potential underdiagnosis. Limited data impedes precise incidence determination, but estimates suggest 1-3% of the population is affected, with increasing cases anticipated as knowledge and diagnostic tools for HIT advance. Despite histamine's physiological importance, elevated levels pose health risks. HIT arises when ingested or internally released histamine surpasses rapid breakdown capacity. Studies link HIT to DAO deficiency and/or impaired DAO activity, often in subgroups with genetic, pathological, or pharmacological factors. DAO cofactor deficiencies like copper, zinc, vitamin C or vitamin B6 may exacerbate DAO impairment. The trial aimed to explore the relationship of histamine elimination, DAO quantity, and essential cofactors for DAO activity. Methods Serum samples from 40 patients underwent analysis for DAO quantity and histamine elimination ratio using Immundiagnostik AG test kits. ELISA quantification employed a sandwich technique with polyclonal antibodies against recombinant DAO. Low DAO levels (< 3 U/ml) indicated histamine intolerance, moderate levels (3 - 10 U/ml) suggested probability, and high levels (< 10 U/ml) initially ruled out intolerance. Histamine elimination efficiency was assessed by comparing spiked sample levels at 0 and 24 hours after incubation, gauging histamine breakdown mechanisms without directly measuring enzyme quantity. Histamine elimination > 40% indicated unlikely intolerance, 25 - 40% (moderate) suggested probability, and < 25% (poor) indicated likelihood. Additionally, vitamin B6 influence was explored using Immundiagnostik AG's microbiological ID-VIT Test system, spiking samples with DAO for supplementation. Six samples with varying B6 levels underwent investigation. Results The investigation revealed that DAO quantity and histamine elimination highlight the enzyme's pivotal role. Distinctions emerged in histamine intolerance classification, with more than 25% of the population showing reduced elimination in samples with moderate DAO levels (3-10 U/mL), and more than 10% showing reduced elimination in samples with high DAO levels (>10 U/mL), suggesting potential DAO inhibition contributing to impaired histamine breakdown. Analyses based on functional vitamin B6 levels demonstrated varying responses to DAO supplementation. Samples with high functional B6 levels (>20 µg/l) showed a 20% increase in elimination with DAO supplementation of 3 U/mL. In contrast, samples with lower B6 levels (<7 µg/l) exhibited minimal to no additional elimination, despite supplemental DAO at 6 U/mL. These findings underscore the nuanced interplay among DAO levels, histamine elimination, and the influence of vitamin B6, providing insights into factors impacting histamine metabolism across diverse patient profiles. Conclusions The data unveil a high potential for differential diagnosis, particularly in the realm of moderate to high DAO quantity, where the dependence on DAO inhibition yields a different classification of HIT probability. Analyzing DAO cofactors, such as vitamin B6, emerges as a valuable complementary tool for the diagnosis and treatment of HIT. These findings underscore the importance of considering DAO levels, their inhibition, and cofactors in a comprehensive approach to enhance the accuracy of HIT assessment and guide effective therapeutic interventions.

Triple synergistic effects of bismuth doping in spinel-LiMn2O4: A path to high-performance electrochemical lithium extraction from salt-lake brine

The electrochemical extraction of lithium-ion from salt-lake brine has attracted significant global interest due to the rising requirement for lithium resources. The electrochemical extraction system based on LiMn2O4 has emerged as one of the most promising methods for commercial lithium extraction. However, the dissolution of manganese in LiMn2O4 material, caused by the Jahn-Teller effect, poses a significant obstacle to achieving large lithium extraction capacity and long lifespan simultaneously. In this study, we addressed the issue by incorporating Bi3+ into the material. The resulted LMBO material displays a truncated octahedral morphology, with {100} crystal faces facilitating Li+ diffusion. Additionally, Bi3+-doping inhibits the Jahn-Teller effect and expands the Li+ diffusion pathway, thereby, enhancing the stability and Li+ diffusion rate of LMO. In particular, LMBO-2 material exhibits an excellent lithium ion diffusion rate of 2.03 × 10−9 cm2·s−1, and demonstrates outstanding Li+ release efficiency, which reaches 26.46 mg·g−1 per cycle with an average energy consumption of 2.04 Wh·mol−1 in the 30 mmol⋅L−1 simulated salt-lake brine. In simulated Zabuye brine solution, LMBO//Ag system displayed an admirably release capacity of 26.17 mg·g−1 characterized by an ultra-low Li/Na ratio, with Li/Na ratio in recovery solution reaching as high as 0.54. These significant findings advance practical applications of LiMn2O4 in brine lithium extraction processes.

Understanding the Roles of Thiophenol-Ligated Ag-Based Nanoclusters on TiO2 during the Catalytic Hydrogenation of Nitroarenes.

Elucidating the correlations between the core structure of atomically precise nanoclusters and their catalytic activities is fundamentalfor exploring highly efficient nanocatalysts. Herein, a series of Ag-based nanoclusters protected by 2,4-dimethylphenylthiophenol (specifically Ag4Pd2(SPhMe2)8 and Ag24M(SPhMe2)18 where M = Ag, Pd, and Pt) were synthesized and deposited on TiO2 supports as heterogeneous catalysts for the selective hydrogenation of nitroarenes with NaBH4 as the reductant. It was found that Ag4Pd2(SPhMe2)8 could spontaneously lose its ligands during catalysis, leading to the formation of polydispersed AgPd nanoparticles. This transformation endows the system with extraordinary activity for driving the hydrogenation of nitroarenes. However, the Ag24M (M = Ag, Pd, and Pt) systems, maintain their core structures during catalysis. They follow the generally reported ligand-mediated hydride-involved process, with catalytic activities depending on the central atom (Pt > Pd > Ag), which affects the hydride transferred from the nanoclusters to the reactant to regulate the catalysis.

Molecular dynamics simulation of the diffusion behaviour in Ti–Ag using diffusion couple method

The diffusion behaviour of the Ti–Ag system was investigated using classical molecular dynamics by simulating a diffusion couple at various temperatures. One bulk of the diffusion couple consisted of titanium atoms arranged in a hexagonal close-packed (hcp) structure, i.e., α-Ti, and the other consisted of silver atoms arranged in a face-centred cubic (fcc) structure. The modern second nearest-neighbour modified embedded-atom method (2NN-MEAM) interatomic potential was used. The mean square displacement (MSD) of Ti atoms diffusing into Ag and Ag atoms into α-Ti was recorded during the simulation. Diffusion coefficients were determined from the slopes of lines fit to linear regions of MSD dependence on time. The Arrhenius relation was used to determine the activation energy and the frequency of attempts. The activation energy of Ti was 0.61eV and frequency of attempts 1.90⋅10−8m2s−1. The determined activation energy of Ag and frequency of attempts were not considered reliable because the Ag diffusion coefficient did not grow exponentially with temperature. Ti atoms penetrated deeper and greater amounts into Ag than Ag into α-Ti and also had a greater diffusion coefficient at all temperatures. The results were compared with the available experimental data, and for these purposes, self-diffusion in α-Ti and Ag was further investigated. Finally, it was determined that Ag diffuses in α-Ti by hopping over interstitial positions and Ti in Ag via vacancies.

Prediction of ferromagnetism in GaN:Ag and SiC:Ag nanotubes

Ferromagnetism in single-walled (6,0) GaN(SiC):Ag nanotubes were studied based on ab initio simulations within a pseudopotential method. For the GaN:Ag single-walled nanosystems, the width of the band gap reduces with the increase of dopant concentration. While Ag-doped SiC nanotubes, the band gap of majority-spin states decrease and these systems show metallic character. The first-principles results of total energies for SiC(GaN):Ag nanotubes predicted the stability of the ferromagnetic and antiferromagnetic phase, respectively. The obtained values of total magnetic moments of Ag-GaN and Ag-SiC systems are ∼2.0 and ∼3.2 μB, respectively. The analysis of the results of density of states show the significant contribution to the magnetization of both defected GaN:Ag and SiC:Ag systems come from three nitrogen and carbon atoms which are bonded with the dopant. First-principles investigation, suggest that the SiC(GaN):Ag nanotubes can be made into magnetic materials, and these are promising candidates for electronic, optoelectronic, and spintronic devices.

Multistage regulation of LiMn2O4 electrode for electrochemical lithium extraction from salt-lake

The sustainable development of future energy relies significantly on the abundant lithium resources present in salt-lake brines. LiMn2O4 (LMO) electrochemical Li+ pump has garnered substantial attention due to its capacity to efficiently extract lithium resources from aqueous solutions with minimal energy consumption. However, the industrial application of LMO electrodes is often limited by Mn dissolving during cycles, as well as the complex and variable brine environment. To address these challenges, this study conducted a multistage regulation of LMO electrodes. Originally, the sol-gel technique was used to prepare CePO4 loading LMO. Due to CePO4 rivet load reforming LMO surface charge, the best-performing 1 wt% CePO4-loaded LMO exhibited a remarkable capacity retention rate of 83.8 % after 30 cycles. Subsequently, a comprehensive hydrophilic modification was applied to the entire electrode. 20%PAA-1CP-LMO//Ag system displayed an admirably release capacity of 24.7 mg·g−1 in Zabuye real brine characterized by an ultra-low Li/Na ratio, with Li/Na ratio in recovery solution reaching as high as 0.62.

Peritectic solidification patterns in the Zn–Ag system captured in three- and four-dimensions

Microstructure selection in two-phase peritectic alloys has been a long-standing topic of fundamental importance. The bicontinuous microstructures arising from peritectic solidification have presented significant challenges for analysis due (in part) to our reliance on two-dimensional (2D) sections, which limits our ability to interpret the full three-dimensional (3D) complexity. Additionally, understanding growth mechanisms based solely on postmortem data has proven to be challenging because the extent of the solid-state peritectic transformation is unknown. Here, we employed X-ray imaging techniques to acquire detailed 3D data and visualize in real-time the dynamics of peritectic solidification in a model system of composition Zn-9.53 wt.% Ag. This paper offers a detailed examination of the origin of two-phase (Zn) + AgZn3 microstructures during directional solidification: specifically, our work investigates the influence of velocity, thermal gradient, and sample size on microstructure selection, namely, rod-like, singly-banded, and multiply-banded structures. Importantly, we find at low velocities V (0.07–0.1 μm/s) and a low thermal gradient G (3 K/mm) the emergence of peritectic (Zn) channels, interwoven within and between primary AgZn3 columnar grains. While these microstructures are suggestive of coupled growth morphologies, real-time imaging proves that the two solids are instead decoupled at the growth front. Meanwhile, at thermal gradients 10× higher, we observe a partially dendritic and partially banded structure that has not been reported before, to the best of our knowledge. We initiate a discussion on the formation of such structures, with broad implications to a wide range of metallic, semi-metallic, and organic peritectic alloys.

In English

Currently, textile and food industries produce a significant volume of sewages containing azo dyes and other organic pollutants. These effluents are serious environmental threats, so new methods for their treatment and the degradation of azo dyes are attracting much attention. Composite materials based on TiO2 modified by noble metals and nanoceria show high activity in the photodegradation of organic contaminates and are proposed for hydrogen synthesis as well. To optimize the treatment of contaminants, different processes can combine including the strategies of adsorption, photoluminescence, photocatalysis, etc. The synthesized TiO2-based nanomaterials (sols, powders) will be exploited for bioremediation due to their small size and surface plasmon resonance from noble metals. Binary nanocomposites based on TiO2 were obtained by the chemical co-precipitation method from solutions of titanium tetraisopropoxide (TTIP) and inorganic salts of cerium, silver, and palladium. It has been stated that TiO2 is represented by anatase with primary particle size (CSR) from 8.5 to 16.8 nm, depending on the nature and concentration of the dopant. It is shown that Ag is reduced on the surface of anatase particles and blocks their growth, while Pd and Ce penetrate the titanium dioxide matrix in the form of small clusters with the deformation of the anatase crystal lattice. Nanocomposite particles formed loose and fragile aggregates, which spontaneously dispersed in solutions of dyes with the formation of colloid-stable sols, required the use of a centrifugal field for their sedimentation. Nanoparticles of TiO2&Pd were electronegative and others were electropositive according to the values 4.1÷9.6 of ZPC (zero point of charge). It was shown that the particles of all composites sorbed Methylene Blue (MB) without photocatalytic activity under the visible light to any dye. Moreover, anionic dyes such as Orange-G (Or-G) and Methyl Orange (MO) were excellently discolorated in the presence of TiO2&Pd system; cationic dyes of MB and Rhodamine B (RhB) discolorated too with the TiO2, TiO2&CeO2, and TiO2&Ag systems under UV light action. As such, photocatalysis tests showed that Orange-G’s and MO’s discoloration was higher for TiO2&Pd (2 wt. %) and TiO2 systems with the correlation coefficient R2 0.999.

Enhancing Sustainable Crop Production through Innovations in Precision Agriculture Technologies

Precision agriculture technologies provide innovative tools to optimize crop production while minimizing environmental impacts. This review examines recent advances in precision ag systems to enhance sustainable agriculture. Key innovations include: remote and proximal crop sensing techniques leveraging hyperspectral imaging, thermal imaging, and Lidar to assess crop health and stress status; variable rate technologies like targeted sprayers and precision planters to reduce input waste; data analytics and decision support systems that integrate multi-source data streams to guide site-specific intervention; robotics and automation for precision field operations; and advanced breeding techniques and genomic tools enabling development of stress resilient, high yielding varieties. Adoption barriers, future technology trajectories, and priority research needs are discussed to further advance precision solutions that support productivity, efficiency, and sustainability goals.

Atomic Layer Deposition of Antibacterial Nanocoatings: A Review.

In recent years, antibacterial coatings have become an important approach in the global fight against bacterial pathogens. Developments in materials science, chemistry, and biochemistry have led to a plethora of materials and chemical compounds that have the potential to create antibacterial coatings. However, insufficient attention has been paid to the analysis of the techniques and technologies used to apply these coatings. Among the various inorganic coating techniques, atomic layer deposition (ALD) is worthy of note. It enables the successful synthesis of high-purity inorganic nanocoatings on surfaces of complex shape and topography, while also providing precise control over their thickness and composition. ALD has various industrial applications, but its practical application in medicine is still limited. In recent years, a considerable number of papers have been published on the proposed use of thin films and coatings produced via ALD in medicine, notably those with antibacterial properties. The aim of this paper is to carefully evaluate and analyze the relevant literature on this topic. Simple oxide coatings, including TiO2, ZnO, Fe2O3, MgO, and ZrO2, were examined, as well as coatings containing metal nanoparticles such as Ag, Cu, Pt, and Au, and mixed systems such as TiO2-ZnO, TiO2-ZrO2, ZnO-Al2O3, TiO2-Ag, and ZnO-Ag. Through comparative analysis, we have been able to draw conclusions on the effectiveness of various antibacterial coatings of different compositions, including key characteristics such as thickness, morphology, and crystal structure. The use of ALD in the development of antibacterial coatings for various applications was analyzed. Furthermore, assumptions were made about the most promising areas of development. The final section provides a comparison of different coatings, as well as the advantages, disadvantages, and prospects of using ALD for the industrial production of antibacterial coatings.

Watching (De)Intercalation of 2D Metals in Epitaxial Graphene: Insight into the Role of Defects.

Intercalation forms heterostructures, and over 25 elements and compounds are intercalated into graphene, but the mechanism for this process is not well understood. Here, the de-intercalation of 2D Ag and Ga metals sandwiched between bilayer graphene and SiC are followed using photoemission electron microscopy (PEEM) and atomistic-scale reactive molecular dynamics simulations. By PEEM, de-intercalation "windows" (or defects) are observed in both systems, but the processes follow distinctly different dynamics. Reversible de- and re-intercalation of Ag is observed through a circular defect where the intercalation velocity front is 0.5nm s-1 ± 0.2nm s.-1 In contrast, the de-intercalation of Ga is irreversible with faster kinetics that are influenced by the non-circular shape of the defect. Molecular dynamics simulations support these pronounced differences and complexities between the two Ag and Ga systems. In the de-intercalating Ga model, Ga atoms first pile up between graphene layers until ultimately moving to the graphene surface. The simulations, supported by density functional theory, indicate that the Ga atoms exhibit larger binding strength to graphene, which agrees with the faster and irreversible diffusion kinetics observed. Thus, both the thermophysical properties of the metal intercalant and its interaction with defective graphene play a key role in intercalation.

Theoretical and experimental studies on the electrodeposited nanocrystalline Ag coatings from a novel Ag2O-based non-cyanide electrolyte

Functional silver coatings have been widely applied in fields of electrochemical energy conversion systems, electronics industry and antibacterial materials, and exploiting new non-cyanide silver electroplating bath system is of great significance for promoting the application. In this work, a new type of cyanide-free electrodeposited silver (Ag) system was developed with Ag2O as the main salt, 5,5-dimethyl hydantoin (DMH) as the silver ion complexing agent and potassium carbonate as the conductive salt. Comprehensive quantum chemical calculations demonstrate that the new silver-based system has the solvation structure of [Ag(C5H7N2O2)2]−(5N(2)-Ag). To further, roles of additives combination (L-cysteine and 2,2-bipyridine) and their fundamental mechanism on the silver electrodeposition process was further investigated by electrochemical tests and theoretical calculations. First-Principles calculation and simulation of molecular dynamics reveal that this additive couple have coordination interactions with Ag+, while strong adsorption on the Ag (111) surface. SEM and XRD analyses showed that the combination of L-cysteine and 2,2-bipyridine achieved an ideal silver coating with good morphology and a low grain size of 22.1 nm, verifying the great potential of the novel system to prepare high-quality silver coatings.

Pd‐Catalyzed δ‐C(sp3)−H Thiolation of Amino Acid Derivatives

AbstractHerein, we report a protocol for the selective δ‐thiolation of aliphatic α‐amino acids catalyzed by a Pd(II)/Ag(I) system. This reaction employs disulfides as thiolating agents and N‐COPy as directing group, providing valuable non‐proteinogenic amino acid derivatives in moderate to good diastereoselectivities and yields. Remarkably, the method is also suitable for the late‐stage functionalization of a dipeptide. Experimental and DFT studies have provided significant insights into the mechanism and underlying factors controlling the selectivity of the process and determining the key role of the silver salt.

Multifunctional AlPO4 reconstructed LiMn2O4 surface for electrochemical lithium extraction from brine

LiMn2O4 (LMO) electrochemical lithium-ion pump has gained widespread attention due to its green, high efficiency, and low energy consumption in selectively extracting lithium from brine. However, collapse of crystal structure and loss of lithium extraction capacity caused by Mn dissolution loss limits its industrialized application. Hence, a multifunctional coating was developed by depositing amorphous AlPO4 on the surface of LMO using sol-gel method. The characterization and electrochemical performance test provided insights into the mechanism of Li+ embedment and de-embedment and revealed that multifunctional AlPO4 can reconstruct the physical and chemical state of LMO surface to improve the interface hydrophilicity, promote the transport of Li+, strengthen cycle stability. Remarkably, after 20 cycles, the capacity retention rate of 0.5AP-LMO reached 93.6% with only 0.147% Mn dissolution loss. The average Li+ release capacity of 0.5AP-LMO//Ag system in simulated brine is 28.77 mg/(g h), which is 90.4% higher than LMO. Encouragingly, even in the more complex Zabuye real brine, 0.5AP-LMO//Ag can still maintain excellent lithium extraction performance. These results indicate that the 0.5AP-LMO//Ag lithium-ion pump shows promising potential as a Li+ selective extraction system.

First-principles calculation of cresol contaminants removal from wastewater environment

In this study, the environment of different cresol (O-cresol, M-cresol, P-cresol) molecules in wastewater were simulated, so as to construct calculation models for the adsorption of single and multiple cresol molecules on Ag(111) surface. All the first-principles calculations are based on the density functional theory. The analysis of adsorption parameters shows that the aromatic ring plane remained horizontal orientation, but the methyl group and the hydroxyl group tilt upward. With the increasing number of cresol molecules, angles between the aromatic ring plane and the top atomic plane of Ag(111) surface increase, and this phenomenon is more obvious in 1O-1M_Ag(111) system. The angle between the aromatic ring plane of cresol molecule and the top atomic plane of Ag(111) surface does not change significantly when three types of cresol molecules are adsorbed, indicating that there is no strong effect between adsorbed cresol molecule and Ag(111) surface. The shortest atomic distance of 3O_Ag(111) system is 1.418 Å and its corresponding maximum adsorption energy is 13.190 eV. It indicates that the structure is the most stable and the adsorption process is the easiest to occur. Results of electron structure analysis show that the superposition peaks (-1.6eV) of O-p orbital and C-p orbital are closer to the Fermi level during the adsorption of single P-cresol molecule, indicating that the system is unstable. For two cresol molecules, 1O-1P_Ag(111) adsorption system shows more superimposed peaks in the range of (-15∼-2) eV. The number of overlapping peaks of adsorption of three types of cresols decreases due to the addition of the third type of cresol molecule. More charge transfers between Ag(111) surface and cresol molecules are observed in 3O_Ag(111) and 1O-1M_Ag(111) adsorption systems, which confirm the strong adsorption effect between them.

Effect of oxygen on trace impurities in extremely pure metal ingots used for realising ITS-90 fixed point temperatures

The International Temperature Scale of 1990 (ITS-90) provides a scheme for calibrating thermometers which is largely based on the freezing points of pure metals such as indium, tin, zinc, aluminium and silver. The existence of trace impurities in pure metals results in uncertainties in the realization of these freezing points. Several methods such as the sum of individual estimates (SIE) and overall maximum estimate (OME) are used to assess the uncertainties due to the presence of impurities. However, it is becoming evident that the oxidation of impurities results in their precipitation, which means that these insoluble oxides no longer play a significant role in the elevation or depression of the freezing temperature. Hence the conventional correction techniques may overestimate the magnitude of the effect. In this study, the thermodynamic modelling software MTDATA was used to evaluate the effect of oxygen on selected impurities in In, Sn, Zn, Al and Ag by calculating the binary impurity-metal phase diagram in the presence of specific amounts of oxygen. It was found that oxygen has a significant effect on many of the systems studied. The most significant effect was observed in the Ag system, and then, in decreasing order of significance, In, Sn, Zn and Al.

Adsorption of Metal Atoms on SiC Monolayer

The electronic, magnetic, and optical behaviors of metals (M = Ag, Al, Au, Bi, Ca, Co, Cr, Cu, Fe, Ga, K, Li, Mn, Na, Ni) adsorbed on the SiC monolayer have been calculated based on density functional theory (DFT). The binding energy results show that all the M-adsorbed SiC systems are stable. All the M-adsorbed SiC systems are magnetic with magnetic moments of 1.00 μB (Ag), 1.00 μB (Al), 1.00 μB (Au), 1.01 μB (Bi), 1.95 μB (Ca), 1.00 μB (Co), 4.26 μB (Cr), 1.00 μB (Cu), 2.00 μB (Fe), 1.00 μB (Ga), 0.99 μB (K), 1.00 μB (Li), 3.00 μB (Mn), and 1.00 μB (Na), respectively, except for the Ni-adsorbed SiC system. The Ag, Al, Au, Cr, Cu, Fe, Ga, Mn, and Na-adsorbed SiC systems become magnetic semiconductors, while Bi, Ca, Co, K, and Li-adsorbed SiC systems become semimetals. The Bader charge results show that there is a charge transfer between the metal atom and the SiC monolayer. The work function of the K-adsorbed SiC system is 2.43 eV, which is 47.9% lower than that of pristine SiC and can be used in electron-emitter devices. The Bi, Ca, Ga, and Mn-adsorbed SiC systems show new absorption peaks in the visible light range. These results indicate that M-adsorbed SiC systems have potential applications in the field of spintronic devices and solar energy conversion photovoltaic devices.

Double Pseudopolymeric [Au{S2CN(CH2)5}2]2[Ag2Cl4]·CH2Cl2 Complex: Preparation, Principles of Supramolecular Self-Assembly, Thermal Behavior, and Biological Activity against Mycolicibacterium smegmatis Strain

The double Au(III)–Ag(I) complex crystallizing as the solvated form of [Au{S2CN(CH2)5}2]2[Ag2Cl4]· CH2Cl2 (I) was obtained by the reaction of silver(I) N,N-pentamethylenedithiocarbamate with a solution of Na[AuCl4]/5.15 M NaCl. According to X-ray diffraction data (CIF file CCDC no. 2062810), the structural units of the compound are nonequivalent [Au{S2CN(CH2)5}2]+ cations (noncentrosymmetric A and centrosymmetric B and C in a ratio of 2 : 1 : 1), cyclic tetrachlorodiargentate(I) anions, [Ag2Cl4]2–, and solvating CH2Cl2 molecule. The latter is retained in the structure due to two nonequivalent C–H···Cl hydrogen bonds formed with the cyclic [Ag2Cl4]2– anion involving its terminal Cl(1) and bridging Cl(2) chlorine atoms. The supramolecular self-organization of I is based on a system of multiple Ag···S and Cl···S secondary interactions that сombine the ionic structural units of the complex into an intricate two-dimensional pseudopolymer layer. A study of the thermal behavior of I by simultaneous thermal analysis established the conditions for quantitative reduction of bound gold(III) and silver(I). The studied Au(III)–Ag(I) compound exhibits a high level of biological activity against the nonpathogenic M. smegmatis strain.