Journal of Molecular Liquids最新文献

Cobalt is a potential substitute for copper as local interconnects in sub-10 nm interconnects, the chemical mechanical polishing (CMP) of which is quite challenging due to the high chemical reactivity of Co. By using a combination of experiments and theoretical calculations, the optimum corrosion inhibitor of Co is identified and the corrosion inhibition mechanism of TTLYK on Co is further investigated. It investigates the effects of various corrosion inhibitors, including potassium oleate, dodecyl benzene sulphonic acid, octyl hydroxamic acid, and 2,2′-[[(methyl-1H-benzotriazol-1yl) methyl] imino] bis-ethanol (TTLYK) on Co through chemical mechanical polishing and static etching experiments. The results show that among various corrosion inhibitors, TTLYK presents the best corrosion inhibition effect. When the basic slurry contains 10 mM TTLYK, the corrosion inhibition efficiency could reach 96.23 %, the material removal rates of Co is 161.79 nm/min, the static etching rates is 0.85 nm/min, and the material removal selectivity ratio of Co and Ti is 39:1. The results fully meet the requirements of the Co bulk CMP process. It is revealed TTLYK could form a protective layer with a synergistic physical and chemical adsorption on Co, in which the chemical adsorption occurs through the formation of CoN bonds. The adsorption of TTLYK could decelerate the transformation of CoO and Co(OH)₂ to Co₃O₄, and the as formed Co-TTLYK complex provides the main corrosion inhibition.

Efficient extraction of Cs⁺ from aqueous solution was investigated by liquid–liquid extraction based on ionic liquids (ILs). In this study, Di(aminobenzo)-18-crown-6 (DAB18C6) was used as the extractant and three ILs (1-butyl-3-methylimidazolium hexafluorophosphate ([C₄mim][PF₆]), 1-hexyl-3-methylimidazolium hexafluorophosphate ([C₆mim][PF₆]), and 1-butyl-3-methylimidazolium bis-trifluoromethyl sulfonamide ([C₄mim][NTf₂])) were employed as co-extractants in the construction of a liquid–liquid extraction system for efficient and selective extraction of Cs⁺ from aqueous solutions. It was demonstrated that the DAB18C6-[C₄mim][NTf₂] mixed solvent system at 0.12 mol/L DAB18C6, a mass ratio of ILs/CHCl₃ of 1:4 and a volumetric ratio of O/A of 1:1 exhibited a high % extraction of Cs⁺ up to 99.94 %, with a higher selectivity for Cs⁺ relative to coexisting ions such as K⁺ (β_Cs/K = 1216.7) and Rb⁺ (β_Cs/Rb = 139.03). The high selectivity of the extraction system for Cs⁺ was attributed to the lower hydration binding energy of Cs⁺ (−366.51 kJ/mol) and the stronger interaction between DAB18C6 and Cs⁺, g(r) = 12.7. Further, the hydrogen bonding interaction between the amino crown ether and ionic liquid increases the viscosity and surface tension of the extraction system, thus enhancing the stability of the system. Noteworthy, the most stable structure formed by DAB18C6-Cs⁺-[NTF₂]⁻ is attributed to cation exchange. In summary, this study demonstrates the great potential for efficient separation and extraction of cesium from aqueous solutions.

Ascorbic Acid (AA) is a crucial component in the food industry, serving as both a quality and safety criterion. It is used to fortify foods due to its significant role in human health, acting as an antioxidant. Its benefits extend to both product quality and consumer health in the food and cosmetic industry. Due to their physicochemical properties, Natural Deep Eutectic Solvents (NADES) have the potential to be used for the extraction and stabilization of bioactive compounds. The objective of this study is to characterize various NADES, simulate the solubility of AA, evaluate the antioxidant and protective capacity of NADES, and investigate the permeability of this vitamin through the skin and gastrointestinal membrane. Antioxidant capacity was measured using three methods: TEAC, DPPH, and ORAC. The solubility of AA in NADES systems was simulated using the COSMOTherm software. The degradation of AA was monitored by HPLC/UV–Vis for 30 days at two different storage temperatures. Additionally, the membrane solubility was measured using the PAMPA method in both skin and gastrointestinal. The results indicate that organic acid-based NADES are more polar than sugar and polyalcohol-based NADES. The solubility prediction shows that reduced ln(γ) in Choline chloride-based NADES results in low AA solubility, which positively correlates with higher pH values. AA degradation increased at lower pH, and its half-life time was longer at 4 °C, being the best choline chloride (ChChl):xylose. Moreover, betaine:malic acid, ChChl:tartaric acid, and ChChl:lactic acid gave worse stabilizing results than control. According to the PAMPA study, AA in lactic acid:glucose had the highest Pe (permeability coefficient) for both gastrointestinal (Log P_e: −4.99) and skin (Log P_e: −4.78). Malic acid:glucose, on the other hand, had the lowest LogP_e value (−6.9). In this study, some NADES can play a protective role in the preservation of ascorbic acid. This statement could be extended to other bioactive compounds found in NADES extracts that may be impacted by oxidative processes. Moreover, not all NADES stabilized equally AA. These findings could be applied to the formulation of ascorbic acid-containing drugs, cosmetics, and food products.

This research aims to reach a selective nanocomposite based on Cu and TiO₂ nanoparticles (NPs) through a sol–gel followed by chemical reduction. Various methods such as XRD, SEM, TEM, HRTEM, BET, Raman, FTIR, DRS, XPS and PL analysis were used to characterize the prepared NPs. The reduced nature of Cu in nanocomposite was evidenced by its X-ray photoelectron spectral characteristics and its HRTEM image. Due to the presence of Cu NPs, light absorption in solar radiation by nanocomposite was considerably enhanced and caused more efficient charge carriers separation. A CCD was used to evaluate the photoactivity of the solar-driven photocatalyst by degrading methylene blue (MB) as a single model electron-rich organic pollutant. In optimal conditions, the highest photocatalytic activity reached 95.64 %. In this study, band structure and reactive species scavenging results confirmed an S-scheme mechanism for charge carrier transfer during photodegradation. The plasmonic S-scheme TiO₂/Cu₂O@Cu heterojunction photocatalyst exhibited remarkably strong photocatalytic selectivity toward MB in binary mixtures of MB with eosin B and rhodamine B. A preference for degradation of MB over safranin (Saf) is confirmed by the faster degradation rate of MB than that of Saf. S-scheme mechanism, Cu doping and dye sensitization all contributed to outstanding selective photodegradation performance.

By forming strong complexes with oppositely charged polyelectrolytes, cationic surfactants significantly affect their solution properties. We investigated the effect of bound surfactant on the titration behavior of two isomer forms of poly(methacrylic acid), PMA, atactic and isotactic PMA, aPMA and iPMA, respectively, which are known for the cooperative change in chain conformation in water. The bound surfactant micelles increase the initial degree of ionization, α, of carboxyl groups on PMA, shift the conformational transition to higher α and make it narrower, and exclude the complexed chains from the solution. The titration curves were analyzed in the framework of the Henderson-Hasselbalch theory and the Gibbs free energy change of the conformational transition was calculated. The results were discussed in the context of a complex influence of surfactant on the PMA chain conformation in solution. It is proposed that the PMA-surfactant interaction changes from a so-called hydrophobic mode, which is responsible for the solubilization of the unionized and water-insoluble iPMA at low α, to a predominantly electrostatic one at high α, which leads to the precipitation of both aPMA and iPMA from solution. Constant pH simulations using simple coarse-grained models for the PMA polymers and individual surfactants were performed to rationalize the titration behavior of PMAs in the absence and presence of surfactant. By inducing an attractive interaction between PMA monomers, an excellent agreement between the experimental and numerical titration curves was obtained. Such agreement becomes poorer upon the addition of surfactant; however, the main features of the PMA titration curves are preserved, which supports the role of hydrophobic interactions in PMA-surfactant association at low pH values and that of electrostatics at higher pH.

This study endeavored to investigate the effects of salts (NaCl, KCl, and CaCl₂) on the rheological and tribological properties of xanthan gum (XG)-fucoidan mixtures. With increasing salt concentrations, the intrinsic viscosity (56.1–30.9 dL/g) of mixtures decreased, with pronouncedly lower values (30.9–35.8 dL/g) observed with CaCl₂ addition compared to monovalent salts addition (36.4–46.6 dL/g). This indicates a contraction of hydrodynamic size of the polymers due to the charge screening effect of cations and the formation of a more compact conformation in the presence of CaCl₂ than with either NaCl or KCl addition. FTIR analysis revealed changes in the interaction between the two polymers in the presence of each salt. All samples exhibited shear-thinning behavior, and their thixotropic behavior increased as the salt concentration increased. The apparent viscosity and viscoelastic moduli decreased in the presence of monovalent salts but were increased in the presence of CaCl₂. This was attributed to the crosslinking effect of Ca²⁺; Na⁺ and K⁺ did not induce crosslinking. In addition, the friction coefficient (μ) of mixtures containing salts reached the maximum at a lower entrainment speed (0.08–0.17 mm·s⁻¹) than that without salt (1.54 mm·s⁻¹), and the mixtures containing salts exhibited lower maximum μ values (0.28–0.62) compared to that without salt (0.83), indicating an improvement in the lubricant properties of XG-fucoidan mixtures. Our findings may help broaden the application of fucoidan in the food industry.

The study of the interaction between aspartic acid (Asp) and cetyltrimethylammonium bromide (CTAB) reveals important information about surfactant organization, surface tension, critical micelle concentration (CMC), and surface pressure. Because of enhanced surfactant solubility brought about by electrostatic interactions, Asp’s ionization lowers CTAB’s CMC. The maximal surface excess concentration falls with increasing Asp concentration, suggesting competition for surface adsorption. The minimum occupied area per surfactant molecule increases at the same time, indicating changed surfactant activity at the interface between air and water. Higher CTAB concentrations are associated with a decrease in surface tension, which suggests that when Asp concentration rises, micelle formation would be promoted. Saturation effects, on the other hand, happen at high Asp concentrations and interfere with micelle formation. These tendencies are supported by surface pressure measurements, highlighting the significance of ionic interactions in micelle behavior.

Moreover, surfactant structuring is impacted by the packing parameter decreasing as Asp concentration increases. The changing balance between hydrophilic and hydrophobic interactions within the CTAB/Asp micellar complexes is further explained by variations in degree of counterion dissociation of micelles ($\alpha )$ values. The complex dynamics of ionic interactions and their impact on surfactant behavior in CTAB/Asp systems are highlighted by these studies.

Binding of biologically important molecules with plasma proteins highly influence its availability, distribution, and metabolism, and thus has great significance in determining its therapeutic efficiency. Hence, studying its interaction with plasma proteins is prime and inevitable. Herein, we have investigated the molecular interaction of Pexidartinib, a novel, primitive and highly selective therapeutical agent against CSF-1R overexpression, with human serum albumin (HSA) and bovine serum albumin (BSA) using various spectroscopic methods, docking and simulations. The intrinsic fluorescence of the proteins considerably quenched on PEX addition accompanied by a slight blue shift. The complex formation between PEX and BSA/HSA induced some alterations in the molecular milieu of the tryptophan residues. The active binding locus was found to be within the hydrophobic cavity of Sudlow site I of both BSA and HSA. The binding dynamics suggest the interplay of hydrogen bonding and hydrophobic interactions in complex stabilisation. MD simulations provides valuable insights into the dynamic facets of the molecular recognition processes involved and governs the stability factor of protein post ligand complexation.

This paper reports densities and viscosities for the mixtures of D-glucosamine hydrochloride (GlcN·HCl) and N-acetyl-D-glucosamine (GlcNAc) with aqueous solutions of 1-hexyl-3-methylimidazolium chloride, [Hmim]Cl, between 293.15 and 318.15 K in 5 K increments and atmospheric pressure. Leveraging this data, we calculated volumetric properties such as apparent molar volume, $V_{\varphi }$, limiting partial molar volume, $V_{\varphi }^0$, and standard molar volume of transfer, $\Delta V_{\varphi }^0$. We handled viscosity data to compute the viscosity B-coefficient and several activation parameters of viscous flow. Some of these are relevant in discussing interactions between monosaccharides (solute) and [Hmim]Cl (co-solvent) in aqueous media. The solute–solvent interactions were discussed based on ionic/ hydrophilic/ hydrophobic interactions using the co-sphere overlap model. $\Delta V_{\varphi }^0$ > 0 indicates that ionic/hydrophilic interactions predominate in the studied systems and are stronger in GlcN·HCl solutions than in GlcNAc at low [Hmim]Cl molalities. At higher [Hmim]Cl concentrations, decreasing values of $\Delta V_{\varphi }^0$ suggest the dominance of hydrophobic interactions over hydrophilic/ionic ones. We discuss (using Hepler’s constant and viscosity B-coefficient) the ability of monosaccharides to act as structure maker/breaker in aqueous [Hmim]Cl solutions. This indicates that GlcNAc is a better structure promoter than GlcN⋅HCl in aqueous [Hmim]Cl solutions. Finally, density functional theory (DFT) was used to model the molecular structure and compute the solute–solvent interaction energies using the GAMESS 2016 software.

The cefadroxil sulfoxide (CDSO) para-hydroxy derivative, derived from cefadroxil, has enormous significance in pharmaceutical applications. The cefadroxil sulfoxide (CDSO) compound was synthesized and characterized by spectroscopic (FT-IR, FT-Raman, and UV–Visible) assessments. Computational investigations have been carried out concurrently with a B3LYP-6-311++G(d,p) basis set and density functional theory (DFT). The molecular vibrational assignments, chemical reactivity, electronic properties, and optical activities are calculated using gas and different solvent phases. The stable ground state configuration of the given molecular compound is investigated using PES analysis. Furthermore, the chemical behavior of the CDSO was thoroughly investigated for different solvent aspects through HOMO-LUMO, MEP, UV–Visible and electron-hole excitation analyses. The molecular occupancy, virtual occupancy, and overlapping bonding energies are investigated by TDOS, PDOS, and COOP spectrum studies. Fukui function and dual descriptor investigations extend to the chemical reactivity of individual atomic sites. The intra-molecular analysis provided a deeper understanding of the molecular interactions performed by natural bond orbitals (NBO) and non-linear optics (NLO), which provided optical activity for the title compound. Additionally, electron localization function (ELF), localized orbital locator (LOL), and reduced density gradient (RDG) analyses were also accomplished to provide insight into the delocalized orbitals in the header composite. The molecular docking was achieved, and the ligand with 4EVM protein is providing the potential antimicrobial biological activity (binding energy −7.12 kcal/mol) of the CDSO compound.