Hexaaluminates EuMg0.8Al11O18.8 and GdMg0.8Al11O18.8 with a magnetoplumbite structure were prepared by the citrate sol-gel method and identified by X-ray diffraction analysis, scanning electron microscopy, and EDX-spectroscopy. The enthalpies of formation of EuMg0.8Al11O18.8 and GdMg0.8Al11O18.8 from oxides and elements at 298.15 K were determined from the enthalpies of solution in molten lead borate.
Extensive research has been conducted for the oxidation of cinnamyl alcohol by thallium(III) in aqueous acidic medium with or without ruthenium(III) catalyst through an integrated kinetic, mechanistic, and computational (DFT) approach to explore the effect of catalyst in the oxidation rate. Kinetic investigations indicate that, without a catalyst, the reaction exhibits a first-order dependence on both cinnamyl alcohol and thallium(III), as well as an inverse dependence on hydrogen ion concentration. This implies the participation of a neutral or deprotonated form of the alcohol, and the bimolecular interaction between TlOH2+ and cinnamyl alcohol constitutes the rate-limiting step. But in the presence of the ruthenium(III) catalyst, the system exhibits first-order dependency on both thallium(III) and the ruthenium(III) while demonstrating a variable order concerning cinnamyl alcohol, suggesting a dual-pathway mechanism that incorporates both catalyzed and uncatalyzed processes. The changing order in alcohol indicates the formation of a pre-equilibrium complex between the alcohol and the catalyst. The observed results signify the concurrent participation of all three species in the rate-determining phase. This exemplifies a ternary transition state, in which cinnamyl alcohol establishes a temporary coordination complex with Ru(III), thereafter interacting with thallium(III) to promote electron transfer. The activation parameters derived from Eyring plots for each reaction imply different mechanistic pathways. The catalyzed pathway exhibits increased reactivity and diminished activation barriers, whereas the uncatalyzed route proceeds at a slower rate. Density Functional Theory investigation signifies the existence of a termolecular transition state involving cinnamyl alcohol, thallium(III), and the ruthenium catalyst, accentuating the catalyst’s role as a redox mediator that expedites electron transfer. The novelty of the research lies in the detailed mechanistic understanding of thallium(III)-catalyzed cinnamyl alcohol oxidations in aqueous media with or without ruthenium(III) catalyst supported by the computational analysis and in describing the substantial impact of catalytic intervention on activation parameters and reaction pathways and providing essential insights for the development of effective catalytic oxidation systems.
The mechanism and kinetics of [FeTMDTA(OH)]2–’s (TMDTA = trimethylenediaminetetraacetic acid) interaction with cyanide ions have been investigated using spectrophotometry at 393 nm (the λmax of [Fe(CN)5OH]3–) by monitoring a spike in absorbance. The specified conditions of reaction are; T = 298 K, ionic strength, I = 0.2 M (NaClO4), and pH 10.5. The findings indicate that the reaction comprises three distinct phases; the initial phase involves the generation of [Fe(CN)5OH]3–, the subsequent phase entails the transformation of [Fe(CN)5OH]3– into [Fe(CN)6]3–, and the final phase involves the interaction of [Fe(CN)6]3– with the ligand (TMDTA) released in the initial stage, resulting in the formation of [Fe(CN)6]4–. The interaction of [FeTMDTA(OH)]2– with CN– exhibits a variable order dependency on [CN–] during the initial stage, fluctuating between one to three at elevated and diminished [CN–]. The subsequent phase of the process exhibits a first-order reliance on both [CN–] and [Fe(CN)5OH3–]. The last stage of the reaction adheres to a general second-order kinetics, exhibiting first-order characteristics with respect to both [Fe(CN)5OH3–] and [TMDTA4–]. Studies have also examined the thermodynamically disadvantageous reversed reaction of [Fe(CN)5OH]3– with TMDTA4–, which is merely driven by a substantial excess of TMDTA4–. The reverse reaction demonstrates an inverse first-order reliance in [CN–] and first-order dependences in [TMDTA4–] and [Fe(CN)5OH3–]. The fourth step of the recommended mechanism, which is the rate-determining step, is further supported by the forward reaction rate’s dependency on ionic strength. The suggested mechanistic scheme is further substantiated by the activation parameters of both the inverse and forward reactions during the initial stage of the reaction.
The geometry of a plasma microwave resonator for CVD diamond growth technology was calculated using the Comsol package, which provides the growth of both an undoped diamond in the TM mode and of the doping δ layer in the TE mode. It is shown that sufficiently homogeneous plasma over the diamond growth surface (substrate) can be maintained in the TE mode at a low gas pressure that is optimal for growing the δ layer. The main trends predicted by the simple calculation model developed in the first part of the present communication, in particular, sufficiently high electron temperature and plasma density when using the low-pressure TE mode, are confirmed.
The degree of asymmetry of the excess surface tension (σ) isotherms of boundary binary systems was found to be the main criterion for preliminary assessment of the applicability limits of the Kohler method. For quantification of the degree of asymmetry of the excess surface tension isotherms of binary systems, we used characteristics of the distribution of a random variable (asymmetry coefficient, excess). The surface tension and asymmetry coefficients in boundary binary systems were calculated for 12 ternary systems for which reliable experimental data were available. The ternary systems can be divided into several groups according to the average asymmetry coefficient of two boundary binary melts: insignificant asymmetry (the average value of the asymmetry coefficient is smaller than 0.7; the σ values obtained by the Kohler method coincide with the experimental data within the measurement error); moderate asymmetry (the average value lies in the range from 0.7 to 0.8; the σ isotherms qualitatively describe the experimental curves); and significant asymmetry (the average value is greater than 0.8; the theoretical curves do not describe the experimental curves).
First-principles calculations were performed to investigate the potential of S-doped Mo2C monolayer as an anode material for magnesium-ion batteries. Our results show that the adsorption energies of Mg on the H1, TC1, TMo1, and B4 sites of S-doped Mo2C are –1.647, –1.565, –1.501, and –1.516 eV, respectively, which are 14.5, 9.4, 6.8, and 7.7% lower than those on the pristine Mo2C monolayer. These findings indicate that S incorporation enhances Mg adsorption. Mg diffusion between two adjacent favorable sites via a symmetric site on S-doped Mo2C exhibits fast diffusion. Density-of-states calculations reveal metallic behavior and favorable electronic conductivity for S-doped Mo2C. Moreover, the S-doped Mo2C monolayer delivers a high theoretical capacity of 1040.02 mA h g–1. The open-circuit voltage ranges from 0.32 to 0.87 V, with an average value of 0.51 V. Consequently, S-doped Mo2C is a promising anode candidate for magnesium-ion batteries.
A temperature-dependent Pitzer–Simonson–Clegg (PSC) model for the binary system LiNO3 + H2O was constructed. The phase equilibrium properties of system LiNO3 + H2O were simulated by PSC model, and the temperature-dependent parameters of PSC model were obtained by this work, which well reproduced the thermodynamic properties of the binary system LiNO3 + H2O including water activity, mean ionic activity coefficient, heat capacity, dilution enthalpy and vapor pressure. Meanwhile, the equilibrium phase diagram of the binary system LiNO3 + H2O at 250–420 K were calculated, the result shows that the calculation results were in good agreement with the experimental results reported in the literature.
In this study, the conformational behavior of two dietary dipeptides, H-Trp-Arg-OH (WR) and H‑Trp-Glu-OH (WE), which are agonists of peroxisome proliferator-activated receptor alpha (PPAR-α), was examined using molecular mechanics and molecular dynamics methods. Subsequently, the most stable conformer of each dipeptide, WR and WE, was docked into the PPAR-α ligand-binding domain (PDB ID: 6KB0), DNA (PDB ID: 1BNA), and Human Serum Albumin (HSA; PDB ID: 1AO6) to explore their interaction mechanisms, metabolic roles, and biological activities. The conformational behavior of these dipeptides and the dynamics of their side chains were studied with molecular mechanics, which identified a set of energetically favored conformers. Molecular dynamics studies on the conformational stability of the dipeptides revealed a limited number of stable conformers that tend to adopt unfolded structures. The molecular electrostatic potential (MEP) surface and dipole moment values of the most stable zwitterionic conformation of both dipeptides were calculated at the DFT/B3LYP/6-31++G(d,p) level of theory. Docking studies of WR and WE with DNA (1BNA) showed binding energies of –8.27 and –7.60 kcal/mol, respectively; docking with HSA revealed binding energies of –7.37 and –8.10 kcal/mol, respectively; and docking with 6KB0 showed binding energies of –5.98 and –6.20 kcal/mol, respectively. These docking results clarified the interaction mechanisms between each dipeptide and receptor. Furthermore, the top-scoring WR-6KB0 complex from the docking studies was subjected to 100 ns of all-atom molecular dynamics (MD) simulations to examine the stability of the complex and ligand-receptor interactions in greater detail.
With the aid of density functional theory, the antioxidant properties of resveratrol and its six 2-phenyl naphthalene derivative compounds, as well as their internal influencing factors, were comprehensively analyzed. It was found that the antioxidant activity of 2-phenyl naphthalene compounds is remarkably influenced by the position of the phenol hydroxyl group. The antioxidant activity of compound molecules with a dihydroxy structure is augmented by intramolecular hydrogen bonding. In contrast, the antioxidant activity of the hydroxyl group on the naphthalene ring surpasses that on the benzene ring. This is attributed to the fact that the conjugation of the naphthalene ring is more pronounced, thereby facilitating a higher stability of free radicals. In summary, the higher the antioxidant activity of a given site, the greater the charge on the H atom of the phenolic hydroxyl group and the lower the energy of the hydrogen extraction reaction at that site. Moreover, the stronger the solvent polarity and intermolecular hydrogen bond are, the stronger the antioxidant activity is.
This paper focuses on the preparation, structural characterization, and property investigation of the copper(I) complex [Cu(dppe)(phon)]I based on 1,2-bis(diphenylphosphino)ethane. The target complex was synthesized via a solution method, using 1,2-bis(diphenylphosphino)ethane, cuprous iodide, and 1,10-phenanthroline-5,6-dione as raw materials and acetonitrile as the solvent. It was then characterized by infrared spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible spectroscopy (UV–Vis), and fluorescence spectroscopy. Methylene blue was used to simulate dyeing wastewater, and the single-factor method was employed to study the effects of the initial concentration of methylene blue, illumination time, complex dosage, and temperature on the- efficiency. The results indicated that the optimal photocatalytic degradation performance was achieved at a relatively low initial concentration of methylene blue, an appropriate complex dosage (25 mg), and a temperature of 40°C. Additionally, the copper(I) complex was utilized as a phosphorescent probe for the detection of tetracycline hydrochloride, doxycycline hydrochloride, and chlortetracycline hydrochloride. It was found that the addition of tetracycline antibiotics led to a decrease in the fluorescence intensity of the complex, and the higher the concentration of the antibiotics, the stronger the quenching effect. The detection limit of the phosphorescent probe for tetracycline hydrochloride antibiotics was 3.0 × 10–9 mol/L. This study provides a theoretical basis and practical reference for the application of copper(I) complexes in photocatalytic degradation and tetracycline detection.
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