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A nitrogen K-edge x-ray absorption near-edge structure (XANES) survey is presented for tetrapyrido[3,2-a:2′,3′-c:3″,2″-h:2‴,3‴-j]phenazine (tpphz)-bridged bimetallic assemblies that couple chromophore and catalyst transition metal complexes for light driven catalysis, as well as their individual molecular constituents. We demonstrate the high N site sensitivity of the N pre-edge XANES features, which are energetically well-separated for the phenazine bridge N atoms and for the individual metal-bound N atoms of the inner coordination sphere ligands. By comparison with the time-dependent density functional theory calculated spectra, we determine the origins of these distinguishable spectral features. We find that metal coordination generates large shifts toward higher energy for the metal-bound N atoms, with increasing shift for 3d < 4d < 5d metal bonding. This is attributed to increasing ligand-to-metal σ donation that increases the effective charge of the bound N atoms and stabilizes the N 1s core electrons. In contrast, the phenazine bridge N pre-edge peak is found at a lower energy due to stabilization of the low energy electron accepting orbital localized on the phenazine motif. While no sensitivity to ground state electronic coupling between the individual molecular subunits was observed, the spectra are sensitive to structural distortions of the tpphz bridge. These results demonstrate N K-edge XANES as a local probe of electronic structure in large bridging ligand motifs, able to distinctly investigate the ligand-centered orbitals involved in metal-to-ligand and ligand-to-ligand electron transfer following light absorption. [ABSTRACT FROM AUTHOR]

The (Ti 3 AlC 2 +Al 2 O 3) p /Al 3 Ti composite was fabricated through hot pressing. The Ti 3 AlC 2 (0001)/TiC(111) interface in the (Ti 3 AlC 2 +Al 2 O 3) p /Al 3 Ti composite was clearly observed, and its interface properties were conducted using first-principles calculations. The results show that: for the TiC(111) surface, the surface energy of Ti-terminated TiC(111) is lower than that of C-terminated TiC(111), indicating that Ti-terminated TiC(111) is more stable. For the Ti 3 AlC 2 (0001) surface, surface energy from high to low is: C-terminated > Ti(Al)-terminated > Ti(C)-terminated > Al-terminated Ti 3 AlC 2 (0001) surfaces in environments of Ti-rich and Al-rich, while the stability is opposite. Among the 24 interface models, Ti(Al)-on-top-C1 has the highest work of adhesion (13.1552 J/m2) and the lowest interface energy (−3.3553 J/m2), indicating the best interface bonding strength and stability. During the relaxation process, the stacking sites of the three interface models, which were named C-hcp-hollow-C2, C-fcc-rollow-C3, and Ti(Al)-on-top-C1, changed. By analyzing the electronic structure of eight interface models, it was found that covalent and metal bonds form at the interface, such as Ti-C covalent bond, Al-C covalent bond, C-C covalent bond, and Ti-Ti metallic bond. This indicates that the type of chemical bonds at the Ti 3 AlC 2 (0001)/TiC(111) interface is determined by the TiC(111) surface termination and Ti 3 AlC 2 (0001) surface termination. In the first-principles tensile test, the critical strain and ultimate tensile strength of the Ti(Al)-on-top-C1 interface model are 8 % and 23.55 GPa, respectively. [ABSTRACT FROM AUTHOR]

The ultrafine PtNiRu ternary alloy nanowires exhibit exceptional catalytic activity and durability for both oxygen reduction reaction and methanol oxidation reaction. The incorporation of Ru modulates the d-band center of Pt atoms, facilitating the desorption of oxygenated intermediates and enhancing stability through the formation of robust Pt Ru metal bonds. [Display omitted] Direct methanol fuel cells rely on the efficiency of their anode/cathode electrocatalysts to facilitate the methanol oxidation reaction and oxygen reduction reaction, respectively. Platinum-based nanocatalysts are at the forefront due to their superior catalytic properties. However, the high-cost, scarcity, and low CO tolerance of platinum pose challenges for the scalable application of DMFCs. Herein, we report novel ultrathin ternary PtNiRu alloy nanowires to improve Pt utilization and CO tolerance. These novel electrocatalysts incorporate the oxophilic metal Ru into ultrathin PtNi nanowires, aiming to enhance the intrinsic activity of platinum while leveraging the long-term durability and high utilization efficiency provided by the bimetallic synergistic effect. The PtNiRu NWs significantly enhance both mass activity and specific activity for ORR, performing about 6.9 times and 3.9 times better than commercial Pt/C, respectively. After a rigorous durability test of 10,000 cycles, the PtNiRu NWs only exhibited a 25.2 % loss in mass activity. Additionally, for MOR, the MA and SA of PtNiRu NWs exceed that of Pt/C catalyst by 4.30 and 2.72 times, respectively, and exhibit exceptional resistance to CO poisoning. Theoretical insights from density functional theory calculations suggest that the introduction of Ru modulates the d-band center of the surface Pt atoms, which contributes to decreased binding strength of oxygenated species and an elevated dissolution potential, substantiating the enhanced performance metrics, and the durability enhancement stems from the stronger Pt M bonds than those in PtNiRu NWs resulted from Pt Ru covalent interactions. These findings not only provide a new perspective on platinum-based nanocatalysts but also significantly advance the quest for more efficient and durable electrocatalysts for DMFCs, representing a substantial stride in fuel cell technology. [ABSTRACT FROM AUTHOR]

The refractoriness of the vitrified bond significantly influences the properties of the vitrified metal-composite bond. In this study, we examined the effects of refractoriness and number of vitrified bonds incorporated into vitrified metal composite bonds in diamond abrasive tools. Furthermore, the effects of vitrified metal composite bonds on the microstructure, mechanical properties, and sintering process were systematically evaluated. Techniques, such as X-ray diffraction (XRD), thermogravimetry-differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), and white light interferometry (WLI) were employed to analyze the phase composition of the vitrified metal composite bond, changes during the hot-pressing sintering process, microstructural morphology, and friction and wear behavior of the diamond abrasive composite bond. The flexural and impact strengths of the composite bond decreased with an increase in the refractoriness of the vitrified bond and number of bonds introduced. In particular, as the refractoriness of the vitrified bonds increased, their fluidity decreased. Finally, the hardness of the vitrified metal composite bond containing 3 % vitrified bond (4#) reached 66.34–69.2 HRB, the porosity was 22.08 %, and the surface roughness of the workpiece was 0.06 μm. [ABSTRACT FROM AUTHOR]

Adhesive bonding of composite laminates to metals is an increasingly employed technique to manufacture lightweight structures. However, this type of joints is sensitive to defects and composite delamination near the bonded area. Thus, increasing their damage tolerance is fundamental to design reliable multi-material components. This work is the first step in a project aimed at improving the fracture toughness of Carbon Fibre Reinforced Polymer (CFRP)/metal joints, exploiting Additive Manufacturing (AM) to produce small features on the metal adherend. This first step is devoted to the qualification of the Mode I fracture toughness of the as-built AM surface. Thus, Double Cantilever Beam (DCB) tests are carried out on metal/metal secondary bonded and CFRP/metal co-bonded joints. The metal part is obtained by Selective Laser Melting (SLM) of AlSi10Mg aluminium alloy, without surface pre-treatment to preserve the as-built roughness. The fracture toughness of the AM un-treated joints is also compared to that of joints in which the metal adherend is sandblasted. Optical profilometry is employed to evaluate the surface morphology of both as printed and sandblasted adherends. The results show that the untreated joints have comparable fracture toughness to their treated counterparts, despite manifesting dissimilar failure modes due to the different surface morphologies. [ABSTRACT FROM AUTHOR]

Explosive welding is a crucial technique for fusing metals and creating composite materials. This study investigates various combinations of Al 5052, wire-mesh, SiCp, and Al 1100 through explosive welding, adjusting welding parameters to alter cladded interface morphology. It evaluates resulting composites' microstructure, tensile strength, shear strength, and impact resistance. Optimal welding outcomes occurred at a dynamic bend angle of 17.8 degrees. A wavelength to amplitude ratio of less than 8.4 shows improved clad strength. The maximum impact strength observed was 18.3 N-m in sample E22. The research introduces a 3D welding window, integrating kinetic energy, wavelength-to-amplitude ratio, and dynamic bend angle. This tool correlates microstructural attributes with material properties during the manufacturing process, enhancing understanding. The study emphasizes explosive welding's potential and the importance of comprehending factors affecting product morphology and characteristics. The 3D welding window's development offers promise in optimizing explosive welding and crafting tailored composites. Findings from this research are significant for the materials science and engineering community, offering insights crucial for advancement in the field. Article highlights: Explosive welding enhances metal bonding and composites production. Optimized explosive welding achieved at dynamic bend angle of 17.8°. 3D welding window links kinetic energy, bend angle, and microstructural properties. SiCp reinforcement prevents molten layer formation in clad interface. Understanding parameters vital for creating high-strength composites. [ABSTRACT FROM AUTHOR]

This paper discusses cavitation within a two-phase solid–liquid enclosed system due to interdiffusion. This mechanism is discussed within the context of solid–liquid interdiffusion bonding for metal systems and the voids which are caused by this mechanism. A case study composed of liquid (Sn), Ni3Sn4, and (Ni) phases was used. The mechanical tension and bubble volume resulting from the mechanically enclosed system during isothermal solidification at 250 °C were calculated using a fitted 1D growth model coupled with thermodynamics. Thermodynamic energy calculations showed that it becomes favorable for cavitation after 6 seconds for a starting liquid pocket of 5 µm3. The critical pressure for this cavitation was − 0.029 GPa. The volumetric change for the reaction was determined to be − 12.3 vol pct by a partial molar volume balance. While the volumetric change determined by the thermodynamics found − 7.2 vol pct. The likely presence of unwettable inclusions in non-pure liquids would circumvent this cavitation mechanism, even though cavitation conditions are present. Meaning cavitation for these systems can only be expected when the liquid metal purity is sufficient. Lastly, the bubble growth is attributed to a combination of thermodynamic bubble growth and Kirkendall vacancies. [ABSTRACT FROM AUTHOR]

Metal-ceramic crowns and bridges provide a stable and aesthetic tooth reconstruction. Hot pressing of veneering ceramics to metal substructure minimizes the formation of pores. Within the oral cavity, prosthetic structures are exposed to thermal stress. The study examines the influence of temperature changes on the quality and durability of the metal-ceramic bond using thermocyclic loading. Prior to the ceramic pressing, 40 cylindrical alloy specimens (height: 15 mm, diameter: 7 mm) were treated with abrasive blasting using Al2O3 (250 µm) or SiC (250 µm). They were divided into four groups: two control groups (sandblasted with Al2O3 or SiC) and two groups subjected to thermocyclic simulation. The ceramic-to-metal bond strength was measured with a shear test before and after thermocyclic loading. A statistically significant reduction in the bond strength between the metal substructure and the pressed ceramic was found after thermocyclic exposure. The bond strength decreased by 57% for Al2O3 sandblasted specimens and 36% for those sandblasted with SiC, as against the control group. This indicates that thermocycling weakens the bond between the metal alloy and pressed ceramic. The SiC blasting of the cobalt-chromium alloy results in a higher shear bond strength of the material connection after thermocyclic stimulation than the abrasive blasting with Al2O3. [ABSTRACT FROM AUTHOR]

The behaviour of the interdiffusion layer between the ceramic layer and the metal bonding layer in thermal barrier coatings, resulting from high-energy beam coating deposition, is a critical factor influencing the thermal cycle life of these coatings. Given that the interdiffusion layer at the interface of plasma spray-physical vapour deposition (PS-PVD) coatings has been relatively underexplored and its influencing mechanisms remain unclear, this study investigates how different pre-oxidation layer states affect the thermal cycle life of PS-PVD coatings. Under conditions conducive to effective pre-oxidation film formation and minimal interdiffusion between NiCrAlYSi and 8YSZ, we observed an increase in thermal cycle life from 1000 h at 1100 °C to 2150 h. The application of high-heat flux jets, along with coupling factors related to preheating and pre-oxidation processes, can modulate interdiffusion at the interface. A thinner interdiffusion layer not only reduces oxidation rates but also enhances the longevity of the coating's thermal cycle. Ultimately, cracks may develop within the composite oxide film, leading to coating failure. The Al-rich component present in both the interdiffusion composite oxide diffusion layer and initially deposited gas phase 8YSZ contributes to a reduction in TGO growth rate, as well as interface stress levels. In scenarios involving high-heat flux jet preheating coupled with coating deposition processes, the oxygen ion concentration emerges as a pivotal factor regulating interdiffusion dynamics. This research holds significant implications for elucidating the formation mechanisms underlying interdiffusion layers while simultaneously enhancing PS-PVD coating lifespans. [ABSTRACT FROM AUTHOR]

Double polymer networks (DNs) consist of two interpenetrating polymer networks and can offer properties that are not merely a sum of the parts. Here, we report an elastic DN made from two supramolecular polymers (SMPs) that consist of the same poly(n‐butyl acrylate) (BA) backbone. The two polymers feature different non‐covalent binding motifs, which form dynamic, reversible cross‐links. The polymers were prepared by reversible addition−fragmentation chain‐transfer polymerization of n‐butyl acrylate and either the self‐complementary hydrogen‐bonding motif 2‐ureido‐4[1H]pyrimidinone, or the 2,6‐bis(1′‐methylbenzimidazolyl)pyridine ligand, which forms complexes with metal ions. The supramolecular DN made by these components combines features of the single networks, including high thermal stability and resistance to creep. The DN further exhibits excellent healability and displays a higher extensibility and a higher toughness than its constituents. The mechanical characteristics of the DN can be further enhanced by selectively pre‐stretching one of the networks, which is readily possible due to the reversible formation of the supramolecular cross‐links and their orthogonal stimuli‐responsiveness. [ABSTRACT FROM AUTHOR]

The reactions of [M2(CO)8(NCMe)2] (M=Re, Mn) with thiosaccharin (tsacH) have been investigated. TsacH reacts with [Re2(CO)8(NCMe)2] at room temperature to furnish [Re2(CO)8(μ‐H)(μ‐sac‐κN,S)] (1) and [Re(CO)5(sac‐κS)] (2), while a similar reaction with [Mn2(CO)8(NCMe)2] affords only [Mn(CO)5(sac‐κS)] (3). The dinuclear 1 contains a bridging tsac ligand coordinated to both rhenium centers using the nitrogen and thiocarbonylic sulfur atoms, while the tsac ligand is bonded to the metal center only through the sulfur atom in mononuclear 2 and 3. The molecular structures of 1–3 have also been determined by X‐ray crystallography. [ABSTRACT FROM AUTHOR]

In this study, comparative analysis of calculated and experimental 13C NMR shifts for a wide range of model platinum complexes showed that, on the whole, the theory reproduces the experimental data well. The chemical shifts of carbon atoms directly bonded to Pt can be calculated well only within the framework of the fully relativistic matrix Dirac−Kohn−Sham (mDKS) level (R2 = 0.9973, RMSE = 3.7 ppm); however, for carbon atoms not bonded to metal, a more simple, non-relativistic approach can be used. Effective locally dense basis set schemes were developed for practical applications. The efficiency of the protocol is demonstrated using the example of the isomeric structure determination in case of several possible coordination modes. [ABSTRACT FROM AUTHOR]

A three‐component denitrative cross‐coupling reaction mediated by visible light has been developed. Various 2‐arylvinyl thiophosphate compounds were synthesized with moderate‐to‐good yields using cheap, nontoxic, nonvolatile, and non‐hygroscopic elemental sulfur (S8) as the raw material. These transformations allow the direct formation of C−S and S−P bonds without metal catalyst via a one‐pot procedure. [ABSTRACT FROM AUTHOR]

N-Heterocyclic carbenes (NHCs) have recently emerged as a popular ligand for the functionalization of metal nanoparticles and atomically precise metal clusters. The strong electron-donating properties of NHCs and robust NHC-metal covalent bonding endow metal nanostructures with improved stability and enhanced catalytic performances. In this review, we focus on NHC-coordinated metal nanoparticles and nanoclusters for the electrochemical CO2 reduction reaction (eCO2RR), selective hydrogenation of unsaturated compounds, and asymmetrical catalytic reactions. We discuss the underlying factors that may be at play in determining the improved activity of NHC-functionalized metals and address a few promising perspectives of NHC functionalization for new and better catalytic metal nanostructures. [ABSTRACT FROM AUTHOR]

The synthesis of large, freestanding, single-atom-thick two-dimensional (2D) metallic materials remains challenging due to the isotropic nature of metallic bonding. Here, we present a bottom-up approach for fabricating macroscopically large, nearly freestanding 2D gold (Au) monolayers, consisting of nanostructured patches. By forming Au monolayers on an Ir(111) substrate and embedding boron (B) atoms at the Au/Ir interface, we achieve suspended monoatomic Au sheets with hexagonal structures and triangular nanoscale patterns. Alternative patterns of periodic nanodots are observed in Au bilayers on the B/Ir(111) substrate. Using scanning tunneling microscopy, X-ray spectroscopies, and theoretical calculations, we reveal the role of buried B species in forming the nanostructured Au layers. Changes in the Au monolayer's band structure upon substrate decoupling indicate a transition from 3D to 2D metal bonding. The resulting Au films exhibit remarkable thermal stability, making them practical for studying the catalytic activity of 2D gold. 2D metals are desired for their potential photonic and catalytic properties, but their synthesis is challenging due to the isotropic nature of metallic bonding. Here, the authors report a bottom-up method to fabricate nearly-freestanding 2D Au monolayers on Ir(111) substrates via boron intercalation. [ABSTRACT FROM AUTHOR]

ABSTRACT: Background and Objectives: Today, orthodontic bracket bonding on the tooth surface is a vital phase in any orthodontic therapy as strong tooth-bracket bonding is essential for success and efficiency. Tooth whitening is popular due to tooth discolouration and patient need for esthetic changes. This in vitro study compared the shear bond strength (SBS) and adhesive remnant index (ARI) of brackets bonded with a conventional and moisture-insensitive primer system on tooth surfaces bleached with 35% hydrogen peroxide in dry and moisture conditions. Methods: Fifty-six healthy humans with extracted maxillary first premolars were cleaned using a periodontal curette, rinsed, treated with 35% hydrogen peroxide, and kept in a 0.1% thymol aqueous solution at room temperature. These teeth were embedded in orthodontic acrylic resin in four groups: the conventional primer system in dry conditions, the conventional primer system in moist conditions using artificial saliva, the moisture insensitive primer system in dry conditions, and the moisture insensitive primer system in moist conditions. After bonding metal brackets to tooth surfaces bleached with 35% hydrogen peroxide, universal testing machine and a stereomicroscope were used to calculate SBS and ARI. Results and Discussion: SBS and ARI values were the lowest in the conventional primer system in moist conditions, with statistically significant differences between groups. The study's findings match earlier research. In vivo research should evaluate SBS and ARI to support in vitro findings. Conclusion: In the current study, moisture was found to be a factor affecting SBS and ARI. The moisture-insensitive bonding system was found to be resistant to effects of moisture compared with the conventional system. [ABSTRACT FROM AUTHOR]

In this study, the content of Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn in washed and unwashed lichen Evernia prunastri (L.) Ach. was determined. Solutions similar to acid rain (H2SO4-HNO3- (NH4)2SO4-NH4NO3) with pH 2.02. 2.55, 3.61, 4.33, and 5.15 were used to investigate the desorption of metals from washed lichen Evernia prunastri. The metal analysis was conducted by flame atomic absorption spectrometry (FAAS). Content of Fe and Pb was higher in unwashed lichen, Mn and Ni were similar in washed and unwashed lichen, and Cr, Cu, Cd, and Zn were higher in the washed lichen sample. Using solution with pH 2.02, the percentage of desorbed Cu, Mn, Cd, and Zn was higher than 95%, while for Pb it was ~ 80%. Mn was desorbed in a mass percentage higher than 79% in all simulated acid rain solutions, while the percentage of Cr desorption was less than 1%. Solutions with pH 3.61, 4.33, and 5.15 desorbed all metals except Mn in a percentage lower than 68%. The results indicate that the lichen Everina prunastri can become a secondary environment pollutant and that the mass percentage of desorbed metals depends on the strength of the bond between the metal and the components of the lichen tissue or cell wall, as well as on the pH value of the precipitation with which the lichen comes into contact. [ABSTRACT FROM AUTHOR]

As a subfield of artificial intelligence (AI), machine learning (ML) has emerged as a versatile tool in accelerating catalytic materials discovery because of its ability to find complex patterns in high‐dimensional data. While the intricacy of cutting‐edge ML models, such as deep learning, makes them powerful, it also renders decision‐making processes challenging to explain. Recent advances in explainable AI technologies, which aim to make the inner workings of ML models understandable to humans, have considerably increased our capacity to gain insights from data. In this study, taking the oxygen reduction reaction (ORR) on {111}‐oriented Pt monolayer core–shell catalysts as an example, we show how the recently developed theory‐infused neural network (TinNet) algorithm enables a rapid search for optimal site motifs with the chemisorption energy of hydroxyl (OH) as a single descriptor, revealing the underlying physical factors that govern the variations in site reactivity. By exploring a broad design space of Pt monolayer core–shell alloys (∼17,000$\sim 17,000$ candidates) that were generated from ∼1500$\sim 1500$ thermodynamically stable bulk structures in existing material databases, we identified novel alloy systems along with previously known catalysts in the goldilocks zone of reactivity properties. SHAP (SHapley Additive exPlanations) analysis reveals the important role of adsorbate resonance energies that originate from sp$sp$‐band interactions in chemical bonding at metal surfaces. Extracting physical insights into surface reactivity with explainable AI opens up new design pathways for optimizing catalytic performance beyond active sites. [ABSTRACT FROM AUTHOR]

Simple Summary: This study proposed a new method for extracting E. coli flagella, which served as a template for synthesizing palladium (Pd) nanowires. By improving the flagella extraction process, we successfully produced Pd nanowires with better structure and function, which could have important applications in technology and medicine. Traditional methods often led to impurities that interfered with nanomaterial synthesis, but our method provided a cleaner and more efficient way of producing high-quality nanowires. Using E. coli flagella as a template offered environmental benefits, as it eliminated the need for toxic chemicals and reduced energy consumption. This eco-friendly approach was also safer and more reliable for practical applications. Our research also showed how the functional groups on the flagella surface helped form strong bonds with metals, improving the nanowire formation process. This study highlighted the potential of using biological templates for nanomaterial synthesis, contributing to the development of greener and more efficient technologies. In recent years, the use of bacterial flagella as biomimetic templates has gained increasing attention in nanomaterial synthesis due to their unique structural and functional properties. In this study, we optimized the flagella extraction method and achieved a high concentration of flagella solution. Flagella were isolated from Escherichia coli. Surface characterization revealed that the flagella had abundant functional groups, such as amino and carboxyl groups, which can serve as nucleation sites for the controlled nucleation and growth of metal nanomaterials. Using bacterial flagella as a template, we synthesized one-dimensional palladium nanowires (Fla-Pd NWs). The results of morphological and phase analyses showed that the synthesized palladium nanoparticles were uniformly and densely distributed on the surface of the flagella. Moreover, the Fla-Pd nanowires exhibited superior electrocatalytic activity, which was applied to develop an electrochemical biosensor. This biosensor was used to detect the early breast cancer biomarker microRNA-21 and exhibited a linear range of 0.66–1.98 µmol/L and a detection limit of 0.78 µmol/L. The method demonstrated high selectivity and reusability, making it a promising strategy for early cancer diagnosis. [ABSTRACT FROM AUTHOR]

Reaction between equimolar amounts of 3,3,3′,3′-tetraethyl-1,1′-(furan-2,5-dicarbonyl)bis(thiourea) (H2L) and CuCl2·2H2O in methanol in the presence of the supporting base Et3N gave rise to a neutral dinuclear complex bis­[μ-3,3,3′,3′-tetraethyl-1,1′-(furan-2,5-dicarbonyl)bis(thioureato)]dicopper(II) di­chloro­methane disolvate, [Cu2(C16H22N4O3S2)2]·2CH2Cl2 or [Cu2(L)2]·2CH2Cl2. The aroylbis(thio­ureas) are doubly deprotonated and the resulting anions {L²–} bond to metal ions through (S,O)-chelating moieties. The copper atoms adopt a virtually cis-square-planar environment. In the crystal, adjacent [Cu2(L)2]·-2CH2Cl2 units are linked into polymeric chains along the a-axis direction by inter­molecular coordinative Cu⋯S inter­actions. The co-crystallized solvent mol­ecules play a vital role in the crystal packing. In particular, weak C—Hfuran⋯Cl and C—Heth­yl⋯Cl contacts consolidate the three-dimensional supra­mol­ecular architecture. [ABSTRACT FROM AUTHOR]

In our work, the fabrication, optical investigation along with the characterization of pure, Lanthanum (La)-doped and Ag-La-doped cobalt oxide NPs was performed. The designed nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric (TG-DTG) analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL). Optical investigation has been done using optical profilometry. The outcome of FT-IR spectral bands/peaks of the synthesized NPs evidently imply the occurrence of Co–oxygen bond, a characteristic bonding in metal oxides. The FE-SEM analysis of the metal oxide NPs shows nano wall-like structures. It has been observed that the crystallite dimension of Lanthanum-doped cobalt oxide increases in size as the concentration of La3+ doping increases as shown in HR-TEM images and XRD data. The PL report showed that Lanthanum-doped and Ag–La-doped Co3O4 are the pivotal luminescent components that can efficaciously enhance the luminescence capacity of the La based-doped as well as Ag–La doped Co3O4. The exterior roughness and the topographical pictures of the La–Ag-doped Co3O4 nanoparticles are examined using optical profilometry method. [ABSTRACT FROM AUTHOR]

There is much promise for creating metal organic framework (MOF) films on metal substrates in fields including sensing and electrical conduction. For these applications, direct production of MOF films with strong bonding on metal substrates is extremely desirable. In this study, a simple one-step method without the need for additives or pre-modification is used to directly create zeolitic imidazolate framework-8 (ZIF-8) films with strong bonding on zinc substrate. The formation mechanisms of ZIF-8 film are analyzed. The strong bonding ZIF-8 film can be attributed to an in-situ grown ZnO interlayer between the ZIF-8 and substrate. The growth process shows the formation time of zinc oxide on the substrate, which is subsequently covered by ZIF-8 crystals. The ZnO interlayer results from a combination of decomposition products of the solvent and the zinc ions. Furthermore, the ZnO interlayer serves as a sacrificial precursor for the in-situ nucleation and continuous growth of ZIF-8 film. It serves as an anchoring site between ZIF-8 film and substrate, resulting in strong adhesion. This paper describes a simple and straightforward production process that is expected to provide a theoretical basis for the laboratory preparation of ZIF films. [ABSTRACT FROM AUTHOR]

Ovonic threshold switching (OTS) selectors play a critical role in suppressing the sneak-path current of three-dimensional crossbar integration circuits. Compared to conventional nonmetal-telluride OTS selectors, selectors based on AlxTey glass are found to have both satisfactory on-state current and selectivity. However, it is unclear why the Al-rich AlxTey glass-based OTS selectors have robust insulation properties for reducing the off-state current. This work reveals the structure–property correlations of amorphous AlxTey at the atomic scale by first-principles calculations. It is found that the stoichiometric Al2Te3 glass tends to have a clean bandgap owing to the covalent and dative bonds formed by non-equivalent sp3-hybridized Al orbitals and the lone-pair electrons of Te. Unexpectedly, for Al-rich AlxTey glass (Al2.21Te2.79), the Al–Al bonds formed by redundant Al-atoms have an integrated crystal orbital bond index (ICOBI) of 0.8–0.9, which is much larger than that of Al–Al bonds in pure metals (0.227), indicating they are covalent. It is the covalent Al–Al bonds that ensure the robust insulation characteristics of Al-rich AlxTey glass, while the Te–Te interaction in the Al-poor AlxTey glass (Al1.79Te3.21) produces midgap states, thereby reducing the insulativity. The presented atomic and electronic pictures here will provide useful theoretical insights for designing OTS selectors with improved performances. [ABSTRACT FROM AUTHOR]

Aluminum/carbon nanotubes (Al/CNTs) nanocomposites are intriguing prospects for mechanical and tribology applications. In this study, the double-pressing double-sintering (DPDS) method was used to create Al-based nanocomposites reinforced with CNTs. Al/CNT nanocomposites' wear behavior, as well as their impact and bending strengths, were examined in relation to CNT content (1, 2, 4, 8 and 12 weight percent) and diameter (8, 20 and 40 nm). The wear behavior of Al/CNT nanocomposites was improved upon increasing the content from 0 to 8 wt.% and diameter sizes of CNTs compared with neat Al. This behavior is attributed to the self-lubricating behavior, clustering, and agglomeration of CNTs. The impact and bending strengths of the Al-8 wt.% CNTs with a diameter size of 40 nm increased by about 112%(17j) and 117%(265 MPa) compared with the neat Al sample, respectively. Impact resistance and bending strength were enhanced with increasing diameter of CNTs. The impact and bending strengths of these nanocomposites were impacted by CNT aggregation and the poor bonding strength of the Al/CNT interfaces (formation of Al4C3). SEM and TEM were used to analyze the worn and fractured surfaces of Al/CNT nanocomposites. [ABSTRACT FROM AUTHOR]

Second-order Møller-Plesset perturbation theory (MP2) often breaks down catastrophically in small-gap systems, leaving much to be desired in its performance for myriad chemical applications such as noncovalent interactions, thermochemistry, and dative bonding in transition metal complexes. This divergence problem has reignited interest in Brillouin-Wigner perturbation theory (BWPT), which is regular at all orders but lacks size consistency and extensivity, severely limiting its application to chemistry. In this work, we propose an alternative partitioning of the Hamiltonian that leads to a regular BWPT perturbation series that, through the second order, is size-extensive, size-consistent (provided its Hartree–Fock reference is also), and orbital invariant. Our second-order size-consistent Brillouin-Wigner (BW-s2) approach can describe the exact dissociation limit of H2 in a minimal basis set, regardless of the spin polarization of the reference orbitals. More broadly, we find that BW-s2 offers improvements relative to MP2 for covalent bond breaking, noncovalent interaction energies, and metal/organic reaction energies, although rivaling coupled-cluster with single and double substitutions for thermochemical properties. [ABSTRACT FROM AUTHOR]

Phosphine oxides are an interesting class of compounds possessing tetracoordinate and pentavalent phosphorus atoms and have been employed in a wide range of applications including reagents in organic synthesis, metal extractants, flame retardants, pharmaceuticals, and bioactivity studies. Among all, the degree of basicity of phosphoryl oxygen driven by the nature of substituents influences the electronic properties of the central metal in a complex toward the diversified catalytic processes. Further, the presence of heteroatoms adjacent to the central phosphorus atom enhances the nucleophilicity of the phosphoryl oxygen atom. In view of this, the present review covers the past two decades of remarkable catalytic versatility of P=O‐based metal complexes and describes the governing factors influencing the structural properties and the resultant coordination behavior. Interestingly, some of the P=O bond distances of metal complexes are either longer or shorter compared to their free ligands, indicating the catalytic activity. These complexes can effectively catalyze a wide range of chemical reactions including polymerizations, C−C and Si−C bond activations, oxidation, reduction, hydroformylation, hydrophosphination, hydrogenation and cyclization reactions. Furthermore, this review emphasizes the impact of substituents, solvents, additives, light, and temperature on the catalytic efficiency. [ABSTRACT FROM AUTHOR]

The pure nanostructured anatase titanium dioxide (TiO 2) and subsequent nitrogen–doped derivatives (TiO 2–x N x; where, x = 0.005, 0.01, 0.05) were synthesized by sol–gel auto–combustion technique. XRD analysis confirms the formation of pure anatase phase of TiO 2 up to doping of 1 mol% (x = 0.01) of nitrogen having tetragonal structure with space group of I 4 1 / amd whereas an additional monoclinic phase of TiO 2 –B was observed at 5 mol% of nitrogen doping in TiO 2. This sample has smallest crystallite size of ∼4.7 ± 0.2 nm corresponding to TiO 2 –B phase and ∼12.0 ± 0.1 nm corresponding to anatase phase. XRD also reveals that the crystallite size of all other samples having pure anatase phase ranges between ∼8.7 ± 0.1 nm & 13.9 ± 0.1 nm. The crystalline phase revealed from XRD of all samples was further supported by the Raman analysis. The direct optical band gap of pure TiO 2 (∼3.4 eV) was reduced non–monotonically after nitrogen doping in the ranges from ∼2.8 eV (TiO 1.95 N 0.05) to ∼2.0 eV (TiO 1.99 N 0.01). FTIR spectra confirm the metal oxide bond formation, surface adsorption of water molecules and presence of residual hydroxyl group in all crystalline samples. HRTEM analysis validates the coexistence of secondary phase of TiO 2 –B along with anatase phase of TiO 2 in studied highest doped sample (TiO 1.95 N 0.05) including its broader particle size distribution as compared to pure TiO 2. The electrical studies reveal that the highest values of dielectric constant and ac conductivity can be realized for pure TiO 2 and at 1 mol% (x = 0.01) of nitrogen doping, among all the studied nitrogen doped samples. • Influence of nitrogen doping on the physical properties of anatase TiO 2. • Highest nitrogen doping level in N:TiO 2 possesses structurally dual phase nature. • TEM images also validate the presence of dual phases within the N:TiO 2 lattice. • Nonmonotonic control of optical band gap can be realized via doping of N in TiO 2. [ABSTRACT FROM AUTHOR]

Graphene nanoribbons (GNRs), nanometer-wide strips of graphene, have garnered significant attention due to their tunable electronic and magnetic properties arising from quantum confinement. A promising approach to manipulate their electronic characteristics involves substituting carbon with heteroatoms, such as nitrogen, with different effects predicted depending on their position. In this study, we present the extension of the edges of 7-atom-wide armchair graphene nanoribbons (7-AGNRs) with pyridine rings, achieved on a Au(111) surface via on-surface synthesis. High-resolution structural characterization confirms the targeted structure, showcasing the predominant formation of carbon-nitrogen (C-N) bonds (over 90% of the units) during growth. This favored bond formation pathway is elucidated and confirmed through density functional theory (DFT) simulations. Furthermore, an analysis of the electronic properties reveals metallic behavior due to charge transfer to the Au(111) substrate accompanied by the presence of nitrogen-localized states. Our results underscore the successful formation of C-N bonds on the metal surface, providing insights for designing new GNRs that incorporate substitutional nitrogen atoms to precisely control their electronic properties. The presence of graphitic nitrogen atoms within graphene nanoribbons has been predicted to strongly affect their electronic properties, but its experimental formation within such structures remains challenging. Here, the authors report on the on-surface synthesis of pyridine-extended 7-armchair graphene nanoribbons on Au(111), whereby graphitic nitrogen is preferentially formed after complete planarization through the formation of C–N bonds. [ABSTRACT FROM AUTHOR]

Introduction: Modular hip implants enables a more precise adaptation of the prosthesis to the patient's anatomy. However, they also carry the risk of increased revision rates due to micromotion at the taper junction. In order to minimize this risk, one potential solution is to establish an adhesive bond between the metal taper junctions. Load-stable bonding techniques, already successfully employed in dentistry for connecting materials such as metals and ceramics or different alloys, offer a promising approach. Nevertheless, the bond strength of tapered adhesive bonds in modular hip implants has not been investigated to date. Materials and methods: Twenty-eight tapered junctions, consisting of a taper (female taper) and a trunnion (male taper) were turned using TiAl6V4 ELI (n = 16) and CoCr28Mo6 (n = 12). The process parameters cutting speed (vc = 50 m/min or 100 m/min) and feed (f = 0.1 mm, 0.05 mm or 0.2 mm) were varied for the trunnions. For each set of process parameters, one trunnion and one taper were additionally subjected to sandblasting. To investigate the effect of geometry, angular mismatch in the samples were measured. The taper pairs were bonded with a biocompatible adhesive, and push-out tests were subsequently performed. Results: The push-out forces generated from the taper connections where both tapers were sandblasted showed a mean push-out force of 5.70 kN. For the samples with only the trunnion sandblasted, the mean force was 0.58 kN, while for the samples with only taper sandblasted the mean push-out force was 1.32 kN. When neither of the tapers was sandblasted the mean push-out force was 0.91 kN. No significant effect of the process parameters on the push-out force was observed. Only the reduced valley depth Svk showed a slight correlation for the CoCr28Mo6 samples (R2 = 0.54). The taper pairs with taper mismatch (between trunnion and taper) greater than |0.1°| did not show lower push-out forces than the specimens with lower taper mismatch. Conclusions: Sandblasted and adhesive-bonded tapered connections represent a viable suitable alternative for modular hip implant connections. Slight differences in taper geometry do not result in reduced push-out forces and are compensated by the adhesive. In mechanically joined tapers these differences can lead to higher wear rates. Further investigation under realistic test conditions is necessary to assess long-term suitability. [ABSTRACT FROM AUTHOR]

Borylenes (:B−R) that are built on a single B−R bond between boron and another nonmetallic atom or group are a heated subject of special interest due to their intriguing transition‐metal‐mimicking reactivity, but the relative lack of understanding for the electronic structure and chemical bonding of transition metal borides leads to lingering neglect of metalized borylenes (:B−M) based on covalent B−M bonding. Here we use infrared photodissociation spectroscopy in combination with density functional calculations to study the geometric structure and chemical bonding of boron‐gold carbonyl complex cations. The structure and bonding analyses demonstrated that the BAu(CO)3+ and BAu2(CO)4+ complexes can be described as bis‐carbonyl‐trapped borylene adducts. While the metal‐rich BAu3(CO)4+ complex represents an unusual multicenter‐bond‐stabilized borylene cation with excellent σ‐acidity and π‐backbonding capability for CO activation, featuring Cs symmetry with a quasi‐T‐shaped BAu3+ core. It is manifested that BAu3+ presents greater amphoteric reactivity and improved stability compared to BAu1,2+ due to the presence of the three‐center‐two‐electron Au−B−Au bond. This study discloses a conceptually new platform for accessing reactive metalized borylenes by exploiting the boron‐mediated multicenter‐bond stabilization strategy and using more bench‐stable and ubiquitous metal carbonyl fragments as starting materials, thus providing a broader opportunity for the design of novel chemical structures and catalytic reactions. [ABSTRACT FROM AUTHOR]

Si 3 N 4 ceramics are the new package materials for large-power electronics and devices, which are required to be bonded to the high-thermal-and-electrical-conductivity metal, Cu. Among the methods to join Si 3 N 4 and Cu, active metal brazing (AMB) is widely used, but the joint still faces the challenge of interface bonding reliability for harsh services. Here, a novel approach for enhancement of the Si 3 N 4 AMB joint by regulating interfacial products to be a unitary nanograined TiN layer was proposed. To achieve this, the Si 3 N 4 /Cu AMB joint was obtained with an Ag–Cu–In–Ti foil whose formation mechanism was investigated, and the detailed morphology of TiN + Ti 5 Si 3 bilayer was observed at brazing temperatures from 740 to 800 °C. Based on the bilayer formation process, adding different Mo contents from 5 to 20 wt % to hinder the formation of Ti 5 Si 3 , obtaining a nanograined TiN layer at the interface with hard-to-observed Ti 5 Si 3 particles around. In the seam, Ag and Cu solid solutions and Cu 2 InTi were refined after adding Mo, but Cu 4 Ti and Cu 3 Ti 2 were not generated in the seam, only with CuTi distributed dispersedly. Although the fractures both occurred at the Si 3 N 4 /filler interface, the joint with Mo additions had higher strength than those with Mo-free. This was because the reduced CTE of the filler alleviated the residual stress during brazing, the refinement in microstructure as a consequence of nucleation-points Mo functioned, and the unitary TiN layer allowed the joints to bear more load particularly. As a result, the maximum strength of joints with Mo additions reached 424 MPa, 115 MPa higher than those brazed with a foil, and significantly more reliable than joints reported by other literature. [ABSTRACT FROM AUTHOR]

Hericene is an unusual hexaolefin consisting of three 1,3-diene units located on a rigid bicyclo [2.2.2]octane framework that restricts the geometrical relationships of metal atoms bonded to these olefinic units. In order to explore possible effects of this rigidity limiting metal–metal interaction in polynuclear derivatives possibly stabilizing coordinatively unsaturated species, the structures and energetics of the hericene iron carbonyl complexes (hericene)Fem(CO)n (m = 1, n = 3; m = 2, n = 6, 5; m = 3, n = 9, 8) have been investigated by density functional theory. The lowest-energy (hericene)Fem(CO)3m (m = 1, 2, 3) structures have the cavities of the hericene ligand filled with a single Fe(CO)3 moiety bonded to a 1,3-diolefin unit. Such species have been synthesized by the reaction of Fe2(CO)9 with hericene. For the (hericene)Fe2(CO)5 system, the lowest energy structures are singlet structures with an Fe(CO)3 unit bonded to a 1,3-diene unit in one hericene cavity and an Fe(CO)2 unit in another hericene cavity bonded to three C=C double bonds from two 1,3-diene units. Higher energy (hericene)Fe2(CO)5 structures include a structure in which a single hericene cavity contains a Fe2(CO)4(µ-CO) moiety with each iron atom bonded to a 1,3-diene unit. In addition, both singlet and triplet (hericene)Fe2(CO)5 structures are found in which an Fe(CO)3 moiety and an Fe(CO)2 moiety located in separate hericene cavities are each bonded to a 1,3-diene unit. The lowest-energy (hericene)Fe3(CO)8 structures have two hericene cavities containing Fe(CO)3 moieties fully bonded to 1,3-diene units and a third hericene cavity containing an Fe(CO)2 moiety fully bonded to a 1,3-diene unit. [ABSTRACT FROM AUTHOR]

Ti–6Al–4V and AZ31B alloy sheets were joined in lap joint configuration using cold metal transfer welding with a synergic power source. The torch angle was kept approximately 45° away from the top plate. Wire feed speeds (WFSs) have been varied from 3.0 m/min to 7.0 m/min. Cold metal transfer welding results in good deposition of weld metal at higher WFSs but at the cost of poor bonding and defects. Joints of the best qualities were fabricated at a WFS of 3.0 m/min and a welding speed of 0.6 m/min. The torch angle assisted in the proper deposition of AZ31B weld metal with a good bond between weld metal and Ti–6Al–4V base metal. Microstructural analysis confirms the joint interface integrity by revealing the absence of defects. Also, there is a significant variation among the grain morphology of weld region, transition zone and base metal. The presence of several oxides (MgO4, Al2O3, etc.) and intermetallics (Mg17Al12, Mg7Zn3, AlMg4Zn11, etc.) is indicated by metallurgical analyses. Tensile-shear tests revealed that the joints could sustain the maximum load of 1871 N. Fractography reveals the mixed mode of fracture containing majority brittle, and a ductile failure at a few locations. The unusual fracture at a few locations indicates the presence of oxides in these regions. [ABSTRACT FROM AUTHOR]

Reaction between equimolar amounts of 3,3,3′,3′-tetraethyl-1,1′-(furan-2,5-dicarbonyl)bis(thiourea) (H2L) and CuCl2·2H2O in methanol in the presence of the supporting base Et3N gave rise to a neutral dinuclear complex bis­[μ-3,3,3′,3′-tetraethyl-1,1′-(furan-2,5-dicarbonyl)bis(thioureato)]dicopper(II) di­chloro­methane disolvate, [Cu2(C16H22N4O3S2)2]·2CH2Cl2 or [Cu2(L)2]·2CH2Cl2. The aroylbis(thio­ureas) are doubly deprotonated and the resulting anions {L2–} bond to metal ions through (S,O)-chelating moieties. The copper atoms adopt a virtually cis-square-planar environment. In the crystal, adjacent [Cu2(L)2]·2CH2Cl2 units are linked into polymeric chains along the a-axis direction by inter­molecular coordinative Cu⋯S inter­actions. The co-crystallized solvent mol­ecules play a vital role in the crystal packing. In particular, weak C—Hfuran⋯Cl and C—Heth­yl⋯Cl contacts consolidate the three-dimensional supra­mol­ecular architecture. [ABSTRACT FROM AUTHOR]

Single‐atom catalysts (SACs), featuring highly uniform active sites, tunable coordination environments, and synergistic effects with support, have emerged as one of the most efficient catalysts for various reactions, particularly for electrochemical CO2 reduction (ECR). However, the scalability of SACs is restricted due to the limited choice of available support and problems that emerge when preparing SACs by thermal deposition. Here, an in situ reconstruction method for preparing SACs is developed with a variety of atomic sites, including nickel, cadmium, cobalt, and magnesium. Driven by electricity, different oxygen‐containing metal precursors, such as MOF‐74 and metal oxides, are directly atomized onto nitrogen‐doped carbon (NC) supports, yielding SACs with variable metal active sites and coordination structures. The electrochemical force facilitates the in situ generation of bonds between the metal and the supports without the need for additional complex steps. A series of MNxOy (M denotes metal) SACs on NC have been synthesized and utilized for ECR. Among these, NiNxOy SACs using Ni‐MOF‐74 as a metal precursor exhibit excellent ECR performance. This universal and general SAC synthesis strategy at room temperature is simpler than most reported synthesis methods to date, providing practical guidance for the design of the next generation of high‐performance SACs. [ABSTRACT FROM AUTHOR]

The occurrence characteristics of arsenic in matte phase are unclear, which leads to the current treatment technology not being able to remove arsenic from matte phase significantly, thus causing a large amount of arsenic to affect smelting links such as copper converting and electrolytic refining. This paper uses instrumental analysis such as XRD, SEM-EDS, MLA and chemical analysis methods such as chemical phase extraction to comprehensively analyze the occurrence characteristics of arsenic in matte phase. The results show that the occurrence states of arsenic in matte are mainly arsenic sulfide, arsenic oxide, arsenate and residual arsenic. Most of the arsenic is in residual state in matte; arsenic in matte is extremely stable and difficult to exchange with the outside world; in high-grade matte, the arsenic content is relatively high. The main occurrence state of arsenic is copper-based complex alloy compounds, in which the arsenic content is about 1-10%. Since the metal bond between Cu-As is extremely stable, it is difficult to separate arsenic from it, which is also the key to the difficulty in completely removing arsenic from matte. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are crystalline materials characterized by their porous structures, formed through coordination bonding between metal ions/clusters and multidentate organic linkers. MOFs have emerged as a significant class of materials with applications in energy storage, CO2 adsorption, and catalysis. This study serves as a brief introduction to the currently available synthesis methods of MOFs, aimed at acquainting beginners in the field of chemical engineering with the ongoing developments in MOF research. The discussed synthesis methods encompass traditional solvothermal/hydrothermal approaches, microwave synthesis of MOFs, one-pot synthesis, MOF nanocomposites, isothermal synthesis, and fluid-fluid synthesis. Notably, the MOF/NH2/Fe3O4 combination exhibited enhanced adsorption capacity of 618 mg/g and retained an efficiency of over 90 %. This study displays a valuable technique for designing functional MOF hybrid composites. By combining MOFs with specific materials, numerous advantages can be achieved in the newly created compounds (MOF composites), including synergistic effects beneficial in catalytic applications, and overcoming the challenges associated with using bare MOFs. [ABSTRACT FROM AUTHOR]

The current study is concerned with understanding the synthesis and application of the diversified BaS3:La2S3:Dy1.8 dithiocarbamate sulphide by the single source precursor (SSP) approach. Analytical approaches were used to evaluate the optical, crystalline, vibrational crosslinking, morphological, and thermal properties of BaS3:La2S3:Dy1.8 chalcogenide. The synthesized chalcogenide has an average crystallite size of 16.35 nm and mixed phases, with a direct band gap energy of 3.9 eV. The study of functional groups revealed the presence of metal sulphide bonds. In terms of morphology, BaS3:La2S3:Dy1.8 chalcogenide has an uneven shape with a small amount of aggregation. The electrochemical charge storage behavior of BaS3:La2S3:Dy1.8 was studied using a nickel foam electrode. The trichalcogenide-decorated electrode exhibited charge-storing behavior, with a specific capacitance of 723 F g− 1 determined by cyclic voltammetry. The electrode has a specific power density of 11,166 W kg− 1 and a low series resistance of 0.9 Ω, as shown by impedance measurements. [ABSTRACT FROM AUTHOR]

Objective: Schiff bases are versatile chemical compounds extensively used in various applications, including as catalysts, polymer stabilizers, pigments, dyes, and building blocks for organic synthesis. In addition, they exhibit a wide range of biological activities, such as antifungal, antibacterial, antiviral, antiproliferative, anti-inflammatory, and antipyretic effects. Methods: A novel Schiff base ligand (HL) was synthesized by condensing isatin with 2,6-diaminopyridine and isoleucine, followed by the preparation of transition metal complexes. The ligand and complexes were characterized using techniques such as elemental analysis, IR, 1H-NMR, UV-vis spectroscopy, mass spectrometry, and thermal analysis. Antimicrobial, antiproliferative activities, and structural investigations through X-ray diffraction and scanning electron microscopy were also evaluated. Results: The complexes were identified as [Cr(L)Cl(H2O)]Cl·2H2O, [Fe(L)Cl2], [M(L)]Cl·nH2O, and [M(L)(H2O)2]Cl, where M represents Mn(II), Cu(II), Cd(II), Co(II), Zn(II), and Ni(II). Thermogravimetric analysis showed initial water loss, followed by decomposition of anionic compounds and ligands. The ligand forms a uninegative-tetradentate bond with the metal ions, and all complexes, except Fe(III), exhibit electrolytic behavior. Most complexes displayed tetrahedral geometry, while Ni(II), Co(II), and Zn(II) had octahedral geometry. The metal complexes showed enhanced antibacterial, antifungal, and antiproliferative activity against MCF-7 breast cancer cells compared to the free ligand. Molecular docking studies indicated inhibitory potential against receptors 1GS4, 2HQ6, 3DJD, and 5JPE. Conclusion: These newly synthesized ligands and complexes show promise as therapeutic agents against infections and cancer, though further studies are needed to understand their mechanisms. [ABSTRACT FROM AUTHOR]

The preparation of gel foams with high stability for inhibiting coal spontaneous combustion remains a huge challenge. In this paper, a highly stable gel foam (SCTH) was developed by introducing nano-hydroxyapatite (HAP) into gel foam system (sodium alginate/calcium L-lactate/tannic acid/composite forming agent). The effects of HAP on the foam performances of SCTH were analyzed. The results showed that HAP could improve the stability of SCTH by forming hydrogen bonds, metal ion bonds with the system and interfacial barriers. After 100 days, SCTH without HAP had only 44.8% of the foam volume remaining. The SCTH with 1.2 wt% HAP had 80% of the volume remaining. In addition, the SCTH had better safety. Thermogravimetric analysis showed that the SCTH could improve the maximum weight loss rate temperature, and increase the residual weight of the coal after thermal decomposition. The coal temperature-programmed oxidation experiment showed that the SCTH could increase the temperature of coal entering the rapid oxidation stage from 120 to 190°C, and the CO inhibition rate was 85.3% at 200°C. Fire suppression experiment showed that the SCTH could reduce the temperature of burning coal by 81.9% within 10 min, thus achieving rapid fire suppression. X-ray photoelectron spectroscopy analysis showed that the SCTH could more effectively reduce the total content of C=O and -COO in coal and block the chain cycle reaction of coal. This work presents a new design idea for using multifunctional nanoparticles to prepare highly stable gel foams with excellent inhibition performance of coal spontaneous combustion. [ABSTRACT FROM AUTHOR]

Purpose. To determine the dependence of the change in chemical bond energy, using a quantum mechanical model of the interaction of dopant ions with a metal substrate in the form of a chain of Nfinite centers located along a straight line. Methodology. Numerical calculation of the analytical expressions of a quantum mechanical system consisting of the interaction between metal ions of doping elements and a chain of Nfinite centers. Findings. By solving the Schrödinger equation for a charge moving in the field of a chain with Nfinite centers, expressions for calculating the energy of chemical bonding of dopant ions with metal substrates were obtained. The analytical expressions for calculating the energies of chemical bonds are obtained. The most probable types of chemical bonds during the formation of protective coatings under nonstationary temperature conditions were determined. Originality. Schrödinger’s equation in ellipsoidal coordinates for the motion of electric charges in a field of Nfinite centers located along a straight line was solved and expressions for calculating the energies of chemical bonds were obtained. The solution of the Schrödinger equation is reduced to solving a twocenter problem with a perturbation. The model allows us to understand the dynamics of interaction of metal ions with a substrate in the form of chains of atoms. The tendency of change in the energy of chemical bonding of metal ions with substrates depending on the distance between them and the charge value is established. Practical value. The developed method for calculating the energy of chemical bonding between metal ions of alloying elements with a chain of Nfinite centers will allow one to qualitatively establish the tendency of formation of certain compounds in the process of obtaining protective coatings under nonstationary temperature conditions. The method can be used to calculate the energies of chemical bonds when selecting alloying elements for other methods of creating protective coatings. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to evaluate the effect of different surface treatment methods on the shear bond strength (SBS) of metal brackets bonded to two types of CAD/CAM composite restorations: milled and 3D-printed. Materials and Methods: A total of 160 flat-shaped specimens (10 × 10 × 2 mm3) were prepared from four different CAD/CAM composites; two milled (Lava Ultimate™ [LU] and Grandio™ [GR]) and two 3D-printed (Crowntec™ [CT] and C&B Permanent™ [CB]). These specimens underwent thermocycling (5000 cycles at 5–55 °C), then were categorized based on the surface treatment into four groups (n = 10): Group C (control, no surface treatment), Group HF (treated with 9.6% hydrofluoric acid), Group DB (mechanical roughening by a diamond bur), and Group SB (sandblasting using aluminum oxide). Metal brackets were bonded using Transbond XT Primer and universal adhesive, stored in artificial saliva for 24 h, then thermocycled again. Shear bond strength (SBS) was tested using a universal testing machine until bracket debonding occurred. The adhesive remnant index (ARI) was assessed using a stereomicroscope to quantify the residual adhesive following debonding. Result: Regarding material, GR and LU restorations had significantly higher SBS values compared to CT and CB, ranging from 13.90 MPa to 20.35 MPa. Regarding surface treatment, SB and HF groups showed significantly higher SBS values. The ARI scores showed different adhesive modes of failure, with higher instances of scores 0 and 1, which indicate no or minimal adhesive remaining. Conclusions: Both milled and 3D-printed materials had adequate SBS for clinical use, with milled materials showing superior results. Surface treatments like sandblasting and HF significantly improved bond strength, with adhesive failure being common. [ABSTRACT FROM AUTHOR]

As a promising high‐thermal‐conductivity ceramics, the direct bonding of Si3N4 with metals remains challenging. Here, we employed active metal brazing of Si3N4 ceramics and Kovar alloys using AgCuTi metal filler, and found that the shear strength in the prepared Kovar/AgCuTi/Si3N4 joints depends on the competitive correlation between the interface layers. The competitive consumption for active element Ti by Kovar/AgCuTi interfacial reactions reduced AgCuTi/Si3N4 interface layer thickness and deteriorated final shear strength, even when using a high‐Ti‐content filler. Surface analysis indicated that interfacial fracture between Ag‐based solid solution and Ti5Si3 was the primary cause of failure. Density functional theory (DFT) revealed that Ag (111)/Fe2Ti (001) interface had higher ideal work of adhesion (Wad) than Ag (111)/Ti5Si3 (001) interface, confirming the importance of AgCuTi/Si3N4 interface layer. Ultimately, by adjusting interface reaction layer thickness, the joints reached a high shear strength of 154.3 MPa. [ABSTRACT FROM AUTHOR]

ABSTRACT Energy‐efficient semiconducting BaS:MnS:Sb2S5 has been synthesized using a single source precursor method. The resulting dithiocarbamate metallic sulfide has an average crystallite size of 17.77 nm and a small band gap of 3.82 eV. A functional group investigation revealed the presence of several bonds, including the metal sulfide bond. This sulfide exhibited a double‐step thermal breakdown pattern. BaS:MnS:Sb2S5 particles were formed like cubes and tended to form cube‐like formations. The electrochemical charge‐storing behavior of BaS:MnS:Sb2S5 was investigated using a nickel foam electrode and a sulfide slurry. The fabricated electrode demonstrated a satisfactory capacity for charge storage, with a specific capacitance of 762.83 F g−1. This indicates a substantial amount of potential for long‐term energy storage utilizing electrodes. This electrode has a specific power density of 9084.78 W kg−1 and a low series resistance of (Rs) = 0.71 Ω, as per impedance measurements. Electro‐catalysis produced an OER overpotential and a corresponding Tafel slope of 233 mV and 157 mV/dec from the electrode. Conversely, for HER activity, the obtained overpotential and subsequent Tafel slope were 386 mV and 73 mV dec−1, respectively. [ABSTRACT FROM AUTHOR]

Two isoelectronic and isostructural W(0) and Re(I) complexes mer-W(CO)3(PNP) (1) and [mer-Re(CO)3(PNP)]Cl (2) (PNP = 4,5-bis(diphenylphosphino)acridine) were synthesized and characterized by X-ray diffraction, infrared, electronic absorption and emission spectroscopy, and cyclic voltammetry. Structures of these complexes show a metal center bonded to the pincer ligand and two axial CO and one equatorial CO ligands. DFT calculations showed that the LUMOs of both complexes are the lowest energy π* orbitals localized in the acridine part of the ligand. The HOMO of 1 is dominated by the dπ orbital of W(0) while the HOMO of 2 has a substantial contribution from the highest energy π orbital of the acridine ring. TD-DFT calculations were performed to assist assignment of the UV-vis absorption spectra. The UV-vis absorption spectrum of 1 shows a very low energy W → π* (acridine) metal-to-ligand-charge-transfer (MLCT) absorption band that ranges from visible (500 nm) to near-infrared (>900 nm) regions and an intense acridine π → π* absorption band at 410 nm. There is a blue-green window in the ∼450–500 nm range between the π → π* and W → π*(acridine) MLCT absorptions. The absorption spectrum of 2, dominated by intense π → π* absorptions, shows no distinct low energy MLCT band. Complex 1 is luminescent, displaying acridine-based ππ* fluorescence at 501 nm which is anti-Kasha as it is higher in energy than the lowest energy excited state. [ABSTRACT FROM AUTHOR]

This work aims to amplify the fluorescence of (Z)-4-hetarylidene-5(4H)-oxazolones 1 by suppression of the hula-twist non-radiative deactivation pathway by C^N-orthopalladation of the 4-hetarylidene ring. Different (Z)-4-hetarylidene-2-phenyl-5(4H)-oxazolones, 1a–1c, prepared by the Erlenmeyer–Plöchl method, have been studied. The orthopalladation of (Z)-2-phenyl-4-(5-thiazolylmethylene)-5(4H)-oxazolone (1a) takes place by C-H bond activation of the H4 of the heterocycle and C^N-chelation, giving the dinuclear trifluoroacetate derivative 2a. By further metathesis of bridging ligands in 2a, complexes containing the orthometalated oxazolone and a variety of ligands 3a–5a, were prepared. The study of the photophysical properties of 1a–5a shows that the bonding of the Pd metal to the 4-hetaryliden-5(4H)-oxazolone does not promote, in these cases, an increase in fluorescence. Interestingly, the orthopalladation of (Z)-2-phenyl-4-(4-thiazolylmethylene)-5(4H)-oxazolone (1b) gives orthopalladated 2b, where the incorporation of the Pd to the oxazolone takes place by C-H bond activation of the ortho-H2 of the 2-phenyl group, ring opening of the oxazolone heterocycle and simultaneous N,N-bonding of the N atoms of the thiazole ring and the generated benzamide fragment. This N^N^C-tridentate dianionic bonding mode is obtained for the first time in oxazolones. Despite a similar lock of the hula-twist deactivation, 2b does not show fluorescence. [ABSTRACT FROM AUTHOR]

The development of physically crosslinked hydrogels with excellent mechanical and sensing properties is of importance for expanding the practical applications of intelligent soft hydrogel materials. Herein, after copolymerization of hydroxyl-containing amino acid derivative N-acryloyl serine (ASer) with acrylamide (AM), we introduce Zr4+ through an immersion strategy to construct metal ion-toughened non-covalent crosslinked hydrogels (with tensile strength of up to 5.73 MPa). It is found that the synergistic coordination of hydroxyl and carboxyl groups with Zr4+ substantially increases the crosslinking density of the hydrogels, thereby imparting markedly superior mechanical properties compared to hydroxyl-free Zr4+-crosslinked hydrogels, such as N-acryloyl alanine (AAla) copolymerized with AM hydrogels (with tensile strength of 2.98 MPa). Through the adjustment of the composition of the copolymer and the density of coordination bonds, the mechanical properties of the hydrogels can be modulated over a wide range. Additionally, due to the introduction of metal ions and the dynamic nature of coordination bonds, the hydrogels also exhibit excellent sensing performance and good self-recovery properties, paving the way for the development of flexible electronic substrates with outstanding comprehensive performances. [ABSTRACT FROM AUTHOR]

Oxidative stress caused by pregnancy‐induced hypertension syndrome significantly affects the health of pregnant women. Hydrogen sulfide is a typical gaseous signal molecule against oxidative stress, and it is of profound significance to develop a detection method. In this study, a stimuli‐responsive hydrogel was constructed based on the coordination and bonding principle of metal ions and chitosan (CS) to realize the quantitative detection of hydrogen sulfide (H2S). The chain of CS contains a large number of amino groups and hydroxyl groups, which can form the coordination structure with Cu2+, triggering CS to form a stable hydrogel. The hydrogel can be formed within about 5 s, which has the characteristics of rapid preparation. In the presence of target H2S, the cross‐linking agent Cu2+ in the hydrogel can compete out, resulting in the collapse of the hydrogel and the release of the electrochemical probe. By detecting the concentration of the released electrochemical probe, the quantitative detection of H2S can be achieved. The prepared hydrogel has a good linear relationship with the concentration of H2S from 1 μM to 60 μm. At the same time, the hydrogel has good specificity and stability, and it can be applied to the detection of H2S in serum samples. [ABSTRACT FROM AUTHOR]

Polyurea (PU) elastomers have attracted considerable attention in the field of protective polymeric coatings. In this work, a dithiol‐terminated boronic ester was synthesized and used to incorporate dynamic boron–oxygen (B–O) bonds in the PU main chain based on thiol isocyanate while amino‐terminated polydimethylsiloxane (PDMS) was introduced to retain good chain flexibility. The modified PU elastomer was found to have a microphase‐separated structure in which the hard blocks served as physical crosslinks. The glass transition temperature (Tg) slightly increases when dynamic B–O bonds exist while further introduction of PDMS soft segment can lower Tg to −55.63 °C. The introduction of dynamic B–O bonds and diminished hydrogen bonding led to a decrease in mechanical strength and elongation at break. Interestingly, the simultaneous incorporation of PDMS and dynamic B–O bonds is favorable for strain rate dependence and suppressing stress relaxation. The potential for bond‐exchange interactions between the dynamic B–O bonds and hydroxyl groups on metal surfaces substantially improved the adhesion of the PU elastomer to metal substrates. Therefore, our work can offer valuable insights for the structural design of functional PU coatings tailored for anti‐impact applications. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]