Search Results (342)

The rare earth (RE) aqua 4-nitrophenylacetate (4npa) complexes {[RE(4npa)₃(H₂O)₂]·2H₂O}_n (RE = La (1La), Nd (2Nd)), [Ce(4npa)₃(H₂O)₂]_n (3Ce), and {[RE₂(4npa)₆(H₂O)]·2H₂O}_n (RE = Gd (4Gd), Dy (5Dy), Y (6Y), Er (7Er), Yb (8Yb)) were synthesised by salt metathesis reactions of RE^III chlorides or nitrates with sodium 4-nitrophenylacetate Na(4npa) in aqueous ethanol. The structures of all the complexes were determined by single-crystal X-ray diffraction (SCXRD) except for RE = 4Gd, which was determined to be isomorphous with the 5Dy and 7Er complexes by X-ray powder diffraction (XRPD). All the complexes crystallise as one-dimensional polymers linked by bridging carboxylates. Complexes (1La–3Ce) have mononuclear repeating units with two coordinated waters and ten coordinate RE ions, 1La and 2Nd also have two waters of crystallization, but 3Ce has none. By contrast, complexes (4Gd–8Yb) have binuclear repeating units with a single coordinated water. Isomorphous 5Dy and 7Er have one nine coordinate and one eight coordinate metal ion, whilst isomorphous 6Y and 8Yb have two eight coordinate RE ions. In some cases, bulk powders have structures different from the corresponding single crystals. For example, bulk 1La is isomorphous with 3Ce owing to the loss of water of crystallization, and 8Yb exhibits coordination isomerism between single crystals and microcrystalline powder. Weight loss corrosion tests revealed that {[Dy₂(4npa)₆(H₂O)]·2H₂O}_n (5Dy) has the greatest inhibition efficiency (89%) of the complexes (1La–8Yb). The activities are comparable to those of the corresponding 4-hydroxyphenylacetates (4hpa) and far superior to those of 2-hydroxyphenylacetates (2hpa) and the unsubstituted phenylacetates. Whilst the coordination numbers generally decline with the lanthanoid contraction, there are deviations around 5Dy, 6Y, 7Er, and 8Yb, and the corrosion inhibition is optimised with a midrange size. Full article

The global generation of industrial waste is increasing rapidly, with much of it either landfilled or discharged into marine environments, resulting in severe environmental pollution. To address this issue, extensive research has been conducted on utilizing waste materials as partial replacements for cement. Although concrete incorporating industrial by-products offers environmental advantages—such as reducing pollution and lowering CO₂ emissions—its application has been limited by poor early-age performance. In South Korea, the annual production of ferronickel slag (FNS) now exceeds 2,000,000 tons, yet its usage remains minimal. To improve this early-age performance, researchers have applied steam curing (SC), a method widely used in precast concrete, which can enhance the utilization of FNS-containing concrete. Some studies have individually evaluated the mechanical or microstructural properties of SC effects, but the combined effects of FNS and SC replacement in precast concrete have rarely been addressed. This study applied SC, a method widely used in precast concrete production, to improve the performance of FNS concrete and conducted a comprehensive evaluation to promote its practical application. For this purpose, ordinary Portland cement (OPC) was partially replaced with FNS at rates of 10%, 20%, and 30%. To assess the effects, tests were conducted on hydration heat, SEM, and XRD, along with evaluations of compressive and splitting tensile strength. Results identified 20% as the optimal replacement ratio. At this ratio, chloride penetration resistance and freeze–thaw durability were also assessed. Furthermore, FNS concrete was evaluated under both natural curing (NC, 28 days) and SC conditions to simulate precast production. Under NC, mechanical properties declined as the FNS content increased, whereas under SC, the performance of the 20% replacement mixture was comparable to that of the control. In addition, the chloride diffusion coefficient and freeze–thaw resistance were improved by 11% and 2%, respectively, under SC compared to NC. This study evaluated the feasibility of FNS-containing concrete, and further studies should be conducted to investigate the structural performance of FNS-containing reinforced concrete via methods such as flexural, shear, splicing, and debonding experiments. Full article

Nerolidol (REL), a sesquiterpene with cis and trans isomers, exhibits diverse bioactive and sensory properties. In this study, we integrate single-crystal X-ray diffraction (SC-XRD), molecular docking, molecular dynamics (MD) simulations, and MM/GBSA binding free energy calculations to investigate its inclusion behavior in β-cyclodextrin (β-CD). Crystallization from a cis/trans mixture yielded a complex containing exclusively the trans isomer, forming a 2:1 host–guest assembly where a head-to-head β-CD dimer encapsulates one trans-REL molecule in an extended conformation. Computational models of cis-REL (bent c1 and extended c8 conformers) also stabilized within the β-CD cavity, with the extended conformer showing the most favorable dynamics. The computed binding affinities for all complexes differed by less than the estimated MM/GBSA uncertainty, indicating no statistically significant preference. Since cis/trans separation of nerolidol and related long-chain terpenoids is of considerable interest, our findings suggest that crystallization selectivity in β-CD inclusion complexes cannot be rationalized solely by binding affinity; instead, it likely arises from crystal packing forces and conformational preferences that govern the solid-state assembly. Full article

Supercritical CO₂ (ScCO₂) injection has emerged as a promising method to enhance shale gas recovery while simultaneously achieving CO₂ sequestration. This research investigates how ScCO₂ interacts with water and shale rock, altering the pore structure characteristics of shale reservoirs. The study examines shale samples from three marine shale formations in southern China under varying thermal and pressure regimes simulating burial conditions at 1000 m (45 °C and 10 MPa) and 2000 m (80 °C and 20 MPa). The research employs multiple analytical techniques including XRD for mineral composition analysis, MICP, N₂GA, and CO₂GA for comprehensive pore characterization, FE–SEM for visual observation of mineral and pore changes, and multifractal theory to analyze pore structure heterogeneity and connectivity. Key findings indicate that ScCO₂–water–shale interactions lead to dissolution of minerals such as kaolinite, calcite, dolomite, and chlorite, and as the reaction proceeds, substantial secondary mineral precipitation occurs, with these changes being more pronounced under 2000 m simulation conditions. Mineral dissolution and precipitation cause changes in pore structure parameters of different pore sizes, with macropores showing increased PV and decreased SSA, mesopores showing decreased PV and SSA, and micropores showing insignificant changes. Moreover, mineral precipitation effects are stronger than dissolution effects. These changes in pore structure parameters lead to alterations in multifractal parameters, with mineral precipitation reducing pore connectivity and consequently enhancing pore heterogeneity. Correlation analysis further revealed that H and D₋₁₀–D₁₀ exhibit a significant negative correlation, confirming that reduced connectivity corresponds to stronger heterogeneity, while mineral composition strongly controls the multifractal responses of macropores and mesopores, with micropores mainly undergoing morphological changes. However, these changes in micropores are mainly manifested as modifications of internal space. Siliceous shale samples exhibit stronger structural stability compared to argillaceous shale, which is attributed to the mechanical strength of the quartz framework. By integrating multifractal theory with multi–scale pore characterization, this study achieves a unified quantification of shale pore heterogeneity and connectivity under ScCO₂–water interactions at reservoir–representative pressure–temperature conditions. This novelty not only advances the methodological framework but also provides critical support for understanding CO₂–enhanced shale gas recovery mechanisms and CO₂ geological sequestration in depleted shale gas reservoirs, highlighting the complex coupling between geochemical reactions and pore structure evolution. Full article

Suspended microchannel resonators (SMRs) are powerful tools for mass, density, and viscosity sensing. Among various transduction methods, full piezoelectric transduction offers key advantages, including on-chip integration, low energy dissipation, and linear response. This work explores sub-200 nm Al_0.6Sc_0.4N thin films for SMR transduction, benchmarking them against their well-established AlN predecessor. By integrating the piezoelectric stack into low-stress silicon nitride (ls-SiN_x) beam resonators, we investigate the impact of bottom electrode design, photoresist removal prior to deposition, and deposition bias on film quality. Characterization includes X-ray diffraction (XRD), scanning electron microscopy (SEM), d₃₁ piezoelectric coefficient, relative dielectric permittivity, and breakdown field measurements. Results illustrate the impacts of the studied parameters and demonstrate a fourfold increase in d₃₁, compared to AlN, confirming the strong potential of Al_0.6Sc_0.4N for high-performance SMR transduction. Full article

The reaction of rhodanine vinyl bithiophene (BTR) with molecular dibromine (Br₂) resulted in the formation of compound 1. Single-crystal X-ray diffraction analysis revealed bromination of the terminal thiophenyl ring and the formation of a 1:1 CT “spoke” adduct between the rhodanine thiocarbonyl group and a neutral dibromine (Br₂) molecule. Full article

In this study, three new terphenyl-substituted NPN ligands bearing pyridyl groups, two phosphonites and one diaminophosphine, were synthesized and fully characterized. Their coordination chemistry with copper(I) was investigated using CuBr and [Cu(NCMe)₄]PF₆ as metal precursors, affording six mononuclear Cu(I) complexes, which were characterized using NMR spectroscopy and, in selected cases, single-crystal X-ray diffraction (SCXRD) analysis. The NPN ligands adopt a κ³-coordination mode, stabilizing the copper centers in distorted tetrahedral geometries. The catalytic performance of these complexes in the S-arylation of thiols with aryl iodides was evaluated. Under optimized conditions, complexes 2a and 2b exhibited excellent activity and broad substrate scope, tolerating both electron-donating and electron-withdrawing groups, as well as sterically hindered and heteroaryl substrates. The methodology also proved effective for aliphatic thiols and demonstrated high chemoselectivity in the presence of potentially reactive functional groups. In contrast, aryl bromides and chlorides were poorly reactive under the same conditions. These findings highlight the potential of well-defined Cu(I)–NPN complexes as efficient and versatile precatalysts for C–S bond formation. Full article

The reaction of 2-(3-chloro-5-phenyl-4H-1,2,6-thiadiazin-4-ylidene)malononitrile with ammonia in anhydrous THF, at ca. 20 °C, for 24 h, gave 6-amino-4-phenylpyrrolo[2,3-c][1,2,6]thiadiazine-5-carbonitrile in 95% yield. The product was characterized by ¹H and ¹³C NMR, SC-XRD, MALDI-TOF mass spectrometry, FTIR, and UV-vis spectroscopy. Intermolecular hydrogen bonding interactions were observed in the solid state between the C≡N and N-H groups of adjacent molecules. Full article

N,N,N′-tris(trimethylsilyl)-carboximidamides are effective reagents in synthetic chemistry in reactions with both non-metal and metal halides, because the side product is the mild and volatile ClSi(CH₃)₃ rather than corrosive HCl. The title compound inserts the 2-pyridylamidinate fragment into several non-metal systems, including custom chelating radical ligands. The single-crystal X-ray diffraction structure was determined and modeled by Hirshfeld atom refinement using custom aspherical atomic scattering factors. Excellent data quality led to a model with enhanced precision of all interatomic distances and free refinement of H-atom positions and anisotropic displacement ellipsoids. This structure model is compared to the four previously published analogous structures. Full article

Heavier element analogues of a ketone, a C=O double-bond compound, have been fascinating compounds from the viewpoint of main-group element chemistry because of their unique structural features and reactivity as compared with those of a ketone, which plays an important role in organic chemistry. We will report here the synthesis of diorgano-stannanethione and stannaneselone featuring tin–chalcogen double bonds, which are the heavy-element analogues of a ketone. The newly obtained stannaneselone has been structurally characterized by spectroscopic analyses and single-crystal X-ray diffraction (SC-XRD) analysis, showing the short Sn–Se bond length featuring π-bond character. The obtained bis(ferrocenyl)stannanechalcogenones were found to undergo [2+4]cycloaddition reactions with 2,3-dimethyl-1,3-butadiene, affording the corresponding six-membered ring compound. Notably, thermolysis of the [2+4]cycloadduct of the stannaneselone regenerated the stannaneselone via the retro[2+4]cycloaddition, whereas the sulfur analogue was thermally very stable. Full article

The reduction of Cu(NO₃)₂ by HS^tBu in CH₃CN under Ar atmosphere produces a light-yellow solution containing numerous {Cu_x(S^tBu)_y} species. The addition of different pyridines (py-R) into this solution results in the formation of {Cu₆(S^tBu)₄} hexanuclear complexes. The slow Et₂O diffusion leads to crystals of [Cu₆(S^tBu)₄(2-Me-py)₅(CH₃CN)(NO₃)](NO₃) (1), [Cu₆(S^tBu)₄(Me₃py)₄(NO₃)₂]·3.5CH₃CN (2a), [Cu₆(S^tBu)₄(Me₃py)₅(NO₃)](NO₃)·5CH₃CN (2b), (NHEt₃)[Cu₆(S^tBu)₄(CH₃CN)₃(NO₃)₃]·H₂O (3), [Cu₆(S^tBu)₄(2-Br-py)₄(NO₃)₂]·2-Br-Py (4), [Cu₆(S^tBu)₄(3-Br-py)₆][Cu₆(S^tBu)₄(CH₃CN)₆](NO₃)₄·9CH₃CN (5), and [Cu₆(S^tBu)₄(3-Cl-py)₆][Cu₆(S^tBu)₄(CH₃CN)₆](NO₃)₄·5CH₃CN (6). The titled compounds were characterized by single crystal X-ray diffraction (SCXRD). The Cu···Cu contacts were analyzed with quantum chemical methods. Full article

In this study, a novel anode-supported solid oxide fuel cell (SOFC) comprising a Bi₂O₃-doped NiO-ScSZ anode and an ScSZ electrolyte was successfully fabricated via a low-temperature co-sintering process at 1300 °C. The incorporation of 3 wt% Bi₂O₃ effectively promoted the sintering of both the anode support and electrolyte layer, resulting in a dense, gas-tight electrolyte and a mechanically robust porous anode support. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses confirmed the formation of phase-pure, highly crystalline ScSZ with an optimized microstructure. Electrochemical performance measurements demonstrated that the fabricated cells achieved excellent power density, reaching a peak value of 0.861 W cm⁻² at 800 °C under humidified hydrogen fuel conditions. The cells maintained stable performance under dry methane operation, with a maximum power density of 0.624 W cm⁻² at 800 °C, indicating resistance to carbon deposition. Gas chromatographic analyses further revealed that the Bi₂O₃-doped NiO-ScSZ anode facilitated earlier and more stable electrochemical oxidation of methane-derived species compared with the conventional NiO-YSZ system, even under conditions of an elevated methane partial pressure. These findings demonstrate that Bi₂O₃ co-doping, combined with low-temperature co-sintering, provides an effective approach for fabricating high-performance intermediate-temperature SOFCs with enhanced structural integrity and electrochemical stability. The developed methodology presents a promising pathway toward achieving cost-effective and durable SOFC technologies. Full article

This study systematically investigates the magnetic ordering and magnetocaloric properties of a series of polycrystalline compounds, Gd_1-xDy_xScO₃ (x = 0, 0.1, 0.2 and 1). X-ray powder diffraction (XRD) analysis confirms that all samples exhibit an orthorhombic perovskite structure with a space group of Pbnm. The zero-field cooling and field cooling magnetization curves demonstrate a transition from antiferromagnetic to paramagnetic phases, with Néel temperatures of about 3 K for GdScO₃ and 4 K for DyScO₃. The doping of Dy³⁺ weakened long-range antiferromagnetic order and enhanced short-range magnetic disorder in GdScO₃, leading to vanished antiferromagnetic transition between 2 and 100 K for the sample of x = 0.2. Using the Arrott–Noakes equation, we constructed Arrott plots to analyze the system’s critical behavior. Both the compounds with x = 0.1 and x = 0.2 conform to the 3D-Heisenberg model. These results indicate the weakened long-range antiferromagnetic order induced by Dy³⁺ doping. Significant maximal magnetic entropy change (−Δ$S_{\mathrm{M}}^{\mathrm{M}\mathrm{a}\mathrm{x}}$) of 36.03 J/kg K at 3 K for the sample Gd_0.9Dy_0.1ScO₃ is achieved as the magnetic field changes from 0 to 50 kOe, which is higher than that of GdScO₃ (−Δ$S_{\mathrm{M}}^{\mathrm{M}\mathrm{a}\mathrm{x}}$ = 34.32 J/kg K) and DyScO₃ (−Δ$S_{\mathrm{M}}^{\mathrm{M}\mathrm{a}\mathrm{x}}$ = 15.63 J/kg K). The considerable magnetocaloric effects (MCEs) suggest that these compounds can be used in the development of low-temperature magnetic refrigeration materials. Full article

Understanding the reactivity and the crystallinity of energetic materials in a solvent is significantly important for their synthesis, purification, and recrystallization. Here, the recrystallization of TNBFI (2,4,7,9-tetranitro-10H-benzofuro[3,2-b]indole), a primary explosive with good thermal stability, in different solvents was studied. Four TNBFI solvates, including TNBFI·AC (AC = acetone), TNBFI·2DMSO (DMSO = dimethyl sulfoxide), TNBFI·4DIO (DIO = 1,4-dioxane), and TNBFI·ACN (ACN = acetonitrile), were obtained. The crystal structures of the solvates were determined by single-crystal X-ray diffraction (SCXRD). The molecular packing and intermolecular interactions in the solvate structures were investigated, and their energetic properties were predicted. Among them, TNBFI·ACN showed good detonation performance with a detonation velocity of 6228 m·s⁻¹ and detonation pressure of 16.23 GPa, which was comparable to TNT and with a potential application in both ammunition and industry. These results will be helpful in the synthesis and purification of TNBFI and valuable for the design of the solvate structure for other energetic materials. Full article

The Minghuazhen Formation in the Cangdong Sag of the Bohai Bay Basin is a key sedimentary unit for investigating regional provenance evolution, paleoclimate variations, and hydrocarbon potential in Eastern China. This study integrates mineralogical and geochemical analyses to explore sedimentary characteristics. Techniques include X-ray diffraction (XRD), major/trace element compositions, rare earth element (REE) distributions, and organic carbon content. XRD data and elemental ratios (e.g., Al/Ti, Zr/Sc) suggest a predominant felsic provenance, sourced from acidic magmatic rocks. The enrichment with light rare earth elements (LREE: La–Eu) and notable negative Eu anomalies in the REE patterns support the interpretation of a provenance from the Taihangshan and Yanshan Orogenic Belts. Geochemical proxies, such as the Chemical Index of Alteration (CIA) and trace element ratios (e.g., U/Th, V/Cr, Ni/Co), indicate a warm and humid depositional environment, characterized by predominantly oxic freshwater conditions. Organic geochemical parameters, including total organic carbon (TOC), total nitrogen (TN), and C/N ratios, suggest that organic matter primarily originates from aquatic algae and plankton, with C/N values predominantly below 10 and a strong correlation between TOC and TN. The weak correlation between TOC and total carbon (TC) indicates that the organic carbon is mainly biological in origin rather than carbonate-derived. Although the warm and humid climate promoted the production of organic matter, the prevailing oxic conditions hindered its preservation, resulting in a relatively low hydrocarbon generation potential within the Minghuazhen Formation of the Cangdong Sag. These findings provide new insights into the sedimentary evolution and hydrocarbon potential of the Bohai Bay Basin. Full article