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LiTaSiO5 system is considered as type of solid electrolyte with great potential for application as ionic conductor. It is well-known that it is difficult to obtain pure dense LiTaSiO5 phase by traditional synthesis methods, because dielectric LiTaO3 phase easily precipitates during synthesis, which affects ionic conductivity. In this work, a glass-ceramic electrolyte with main LiTaSiO5 phase was obtained by controlled crystallization of Li2OTa 2O5-2 SiO2 glass without porosity. The precipitation of LiTaO3 phase at the grain boundary was effectively inhibited by adding an appropriate amount of ZrO2. Among all the glass-ceramic samples, the glass containing 4.76mol% ZrO2 had the maximum ionic conductivity of 8.40 × 10−6 S/cm at 25°C, which is two order of magnitude greater than the ionic conductivity of the matrix glass. These glass-ceramic samples have the potential to be used as solid electrolytes in electrochemical applications.

The paper proposes an overview of the primary applications of generalized two-dimensional correlation spectroscopy (2D-COS) to analytical chemistry. 2D-COS is a method used to analyze datasets obtained by spectroscopic measurements. This approach is based on the use of 2D correlation maps to detect and analyze correlations between different spectral regions or data from two measurement methods. The objective of employing 2D-COS is to enhance the volume of analytical information by uncovering latent correlations within the data. Analysis of such correlations for series of spectral data, acquired over a range of analyte concentrations, pH values, or component ratios in mixtures, and also under varying temperatures or other external factors, enables investigating and elucidating chemical processes and interactions. This information is not readily attainable directly from the spectra. In comparison to one-dimensional spectra, 2D-COS excels in the significance of analytical information, particularly in the identification of components and the determination of the composition of complex mixtures. 2D-COS can also be used for monitoring changes in a sample over time, which makes it a valuable tool for studying dynamically evolving systems. Overall, 2D-COS is a sufficiently versatile approach that can be employed in conjunction with numerous methods, addressing a wide range of analytical tasks and complex samples, also without sample preparation. The review highlights achievements in the application of 2D-COS by the beginning of September 2023. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of CO2 and nitrate offers a promising avenue to produce valuable chemicals through the using of greenhouse gas and nitrogen‐containing wastewater. However, the generally proposed reaction pathway of concurrent CO2 and nitrate reduction for urea synthesis requires the catalysts to be both efficient in both CO2 and nitrate reduction, thus narrowing the selection range of suitable catalysts. Herein, we demonstrate a distinct mechanism in urea synthesis, a tandem NO3− and CO2 reduction, in which the surface amino species generated by nitrate reduction play the role to capture free CO2 and subsequent initiate its activation. When using the TiO2 electrocatalyst derived from MIL‐125‐NH2, it intrinsically exhibits low activity in aqueous CO2 reduction, however, in the presence of both nitrate and CO2, this catalyst achieves an excellent urea yield rate of 43.37 mmol ⋅ g−1 ⋅ h−1 and a Faradaic efficiency of 48.88 % at −0.9 V vs. RHE in a flow cell. Even at a low CO2 level of 15 %, the Faradaic efficiency of urea synthesis remains robust at 42.33 %. The tandem reduction procedure was further confirmed by in situ spectroscopies and theoretical calculations. This research provides new insights into the selection and design of electrocatalysts for urea synthesis. [ABSTRACT FROM AUTHOR]

New data on the crystal structure and isomorphism of extra-framework components in the cancrinite-group mineral tounkite have been obtained using chemical and single-crystal X-ray diffraction data, as well as infrared, Raman, ESR, UV–Vis–near-IR absorption and photoluminescence spectroscopy methods. The crystal structure of tounkite is based on the aluminosilicate framework formed by the САСАСВСВСАСВ stacking sequence with ordered Si and Al atoms The framework hosts Losod and liottite cages as well as columns of cancrinite cages. It is shown that tounkite is characterized by wide variations of the chemical composition. Its simplified crystal–chemical formula is (Na+3.89–5.18K+0.15–1.64Ca2+2.30–2.58(Al6Si6O24)(SO42−,S52−,S4) 2−x (Cl−, HS−)1+y·nH2O (x, y, n < 1). The S2⦁− and S3⦁− radical anions may occur in some tounkite samples in minor amounts. These crystal–chemical features indicate that tounkite crystallizes under highly reducing conditions. All studied tounkite samples were polysynthetic twins. A large 10-layed cage formed at the border between twin components, connected by a rotation of 180° around the [001] axis, which may host the large S52− anion. [ABSTRACT FROM AUTHOR]

The new columbite-supergroup mineral dmitryvarlamovite, ideally Ti2(Fe3+Nb)O8, was discovered in weathered alkaline metasomatic assemblages formed after late Riphaean sedimentary carbonate rocks of the Verkhne-Shchugorskoe deposit, Middle Timan Mts., Russia. The associated minerals are columbite-(Fe), pyrochlore-group minerals, monazite-(Ce), xenotime-(Y), baryte, pyrite, drugmanite and plumbogummite. Dmitryvarlamovite occurs as isolated anhedral equant grains up to 0.5 mm across. The colour of dmitryvarlamovite is black, the streak is black and the lustre is submetallic. The new mineral is brittle, with the mean VHN hardness of 753 kg mm–2 corresponding to the Mohs' hardness of 6. No cleavage is observed. The fracture is conchoidal. The calculated density is 4.891 g⋅cm–3. In reflected light, dmitryvarlamovite is light grey; no pleochroism is observed. The reflectance values (R min, % / R max, % / λ, nm) are: 19.8/20.3/470, 18.3/18.9/546, 17.8/18.5/589 and 17.3/17.8/650. The chemical composition is (electron microprobe data, with iron divided into Fe2O3 and FeO based on the charge balance, wt.%): MnO 0.11, FeO 1.51, V2O3 0.89, Cr2O3 0.28, Fe2O3 19.26, TiO2 37.72, Nb2O5 40.08, total 99.85. The IR and Raman spectra indicate the absence of H-, C- and N-bearing groups. The empirical formula is (Fe2+0.08V3+0.05Cr3+0.01Fe3+0.92Ti1.79Nb1.15)Σ4.00O8. The crystal structure was determined using single-crystal X-ray diffraction data and refined to R = 0.048. Dmitryvarlamovite is orthorhombic, space group P 21212, a = 4.9825(6), b = 4.6268(4), c = 5.5952(6) Å and V = 5.5952(6) Å3 (Z = 1). The structure is related to those of wolframite-group minerals but differs in the scheme of cation ordering. The crystal-chemical formula derived based on the structural data is (Ti0.57Nb0.21Fe3+0.15Fe2+0.04V0.02Cr0.01)2(Nb0.36Ti0.33Fe3+0.31)2O8. The strongest lines of the powder X-ray diffraction pattern [ d , Å (I , %) (hkl)] are: 3.58 (40) (011), 2.911 (100) (111), 2.809 (40) (002), 2.497 (38) (020), 2.447 (29) (103), 1.7363 (32) (103) and 1.7047 (29) (220). Dmitryvarlamovite is named after Dmitry Anatol'evich Varlamov (b. 1965). [ABSTRACT FROM AUTHOR]

In our study, we investigated the accelerated aging process of PLA under 253.7 nm UV-C irradiation with the use of the GPC, NMR, FTIR, and DSC methods and formal kinetic analysis. The results of GPC and DSC indicated a significant degree of destructive changes in the PLA macromolecules, while spectroscopic methods NMR and FTIR showed maintenance of the PLA main structural elements even after a long time of UV exposure. In addition to that, the GPC method displayed the formation of a high molecular weight fraction starting from 24 h of irradiation, and an increase in its content after 144 h of irradiation. It has been shown for the first time that a distinctive feature of prolonged UV exposure is the occurrence of intra- and intermolecular radical recombination reactions, leading to the formation of a high molecular weight fraction of PLA decomposition products. This causes the observed slowdown of the photolysis process. It was concluded that photolysis of PLA is a complex physicochemical process, the mechanism of which depends on morphological changes in the solid phase of the polymer under UV radiation. [ABSTRACT FROM AUTHOR]

Fourier transform infrared spectroscopy (FT-IR) is a widely used spectroscopic method for routine analysis of substances and compounds. Spectral interpretation of spectra is a labor-intensive process that provides important information about functional groups or bonds present in compounds and complex substances. In this paper, based on deep learning methods of convolutional neural networks, models were developed to determine the presence of 17 classes of functional groups or 72 classes of coupling oscillations in the FT-IR spectra. Using web scanning, the spectra of 14 361 FT-IR spectra of organic molecules were obtained. Several different variants of model architectures with different sizes of feature maps have been tested. Based on the Shapley additive explanations (SHAP) and gradient-weighted class activation mapping (GradCAM) methods, visualization tools have been developed for visualizing and highlighting the areas of absorption bands manifestation for corresponding functional groups or bonds in the spectrum. To determine 17 and 72 classes, the F1-weighted metric, which is the harmonic mean of the class' precision and class' recall weighted by class' fraction, reached 93 and 88%, respectively, when using data on the position of absorption maxima in the spectrum as an additional source layer. The resulting model can be used to facilitate the routine analysis of spectra for all areas such as organic chemistry, materials science, and biology, as well as to facilitate the preparation of the obtained experimental data for publication. [ABSTRACT FROM AUTHOR]

A new method for the synthesis of reactive oligoimides with terminal nadic groups without the use of toxic reagents is proposed. The synthesis of ROI is carried out in dimethylacetamide (DMAA) in two stages without isolation of an intermediate product. Aromatic diamine is condensed in the first stage with the mixture of aromatic dianhydride and nadic anhydride at 25 °C to form oligoamidoacid. Thermochemical imidization of oligoamidoacid is carried out in the second stage in the presence of a cyclizing system of methyltriethoxysilane and diazobicyclooctane (MTEOS—DABCO) at 140 °C with the formation of oligoimides carrying terminal nadic groups. The structure of the final products was confirmed by 1H NMR and IR spectroscopy. Bis-amidoacid 2a was obtained as an example of a model compound by condensation of 2,2-bis(4-aminophenoxyphenyl)-propane and nadic anhydride (1: 2 mol) and the kinetics of imidization was investigated. It is demonstrated that the imidization reaction is significantly accelerated in the presence of the MTEOS + DABCO system compared to the reaction in the absence of additives. Almost complete conversion of carboxyamide groups into imide cycles is achieved in 30 min, while maintaining unsaturated bonds in the terminal groups. [ABSTRACT FROM AUTHOR]

Destinezite ( Al0.02)(PO4)0.99(SO4)0.90(OH)1.20⋅5.97H2O (Czech Republic) has been studied by thermal and electron-microprobe analyses, X-ray powder diffraction, and by IR, Raman, and Mössbauer spectroscopy. The enthalpy of formation of destinezite (PO4)(SO4)(OH)⋅6H2O from elements ∆fH0(298.15 K) = –4258 ± 12 kJ/mol was determined by the method of solution calorimetry in lead borate 2PbO⋅B2O3 melt on a Setaram (France) Calvet microcalorimeter. The value of its absolute entropy S0(298.15 K) = 462.0 J/(mol K) was estimated, the entropy of formation ∆fS0(298.15 K) = –2054 J/(mol K), and the Gibbs energy of formation from the elements ∆fG0(298.15 K) = –3646 kJ/mol were calculated. [ABSTRACT FROM AUTHOR]

With the aim of controlling the orientation of liquid crystals (LCs) toward realizing external stimuli–responsive materials with tunable functionalities, we synthesized a composite of LCs and metal–organic frameworks (MOFs) by filling LCs into the pores of MOFs (LC@MOFs) for the first time. The included LCs interact with the MOFs through coordination bonds between the cyano groups of the LCs and the metal ions of the MOFs, enabling the orientation of the LC molecules inside the pores of the MOFs and the realization of birefringence of LC@MOFs. The three‐dimensional nanometer interstice frameworks maintained the LC orientation even at temperatures much higher than the isotropic phase transition temperature of bulk LCs. Furthermore, the orientational state changed upon heating or cooling, inducing temperature‐dependent birefringence. This study provides a new approach to the development of stimuli–responsive optical materials and stimuli–responsive MOFs. [ABSTRACT FROM AUTHOR]

Hybrid materials based on calcium phosphates and synthetic polymers can potentially be used for caries protection due to their similarity to hard tissues in terms of composition, structure and a number of properties. This study is focused on the biomimetic synthesis of hybrid materials consisting of hydroxiapatite and the zwitterionic polymers polysulfobetaine (PSB) and polycarboxybetaine (PCB) using controlled media conditions with a constant pH of 8.0–8.2 and Ca/P = 1.67. The results show that pH control is a dominant factor in the crystal phase formation, so nano-crystalline hydroxyapatite with a Ca/P ratio of 1.63–1.71 was observed as the mineral phase in all the materials prepared. The final polymer content measured for the synthesized hybrid materials was 48–52%. The polymer type affects the final microstructure, and the mineral particle size is thinner and smaller in the synthesis performed using PCB than using PSB. The final intermolecular interaction of the nano-crystallized hydroxyapatite was demonstrated to be stronger with PCB than with PSB as shown by our IR and Raman spectroscopy analyses. The higher remineralization potential of the PCB-containing synthesized material was demonstrated by in vitro testing using artificial saliva. [ABSTRACT FROM AUTHOR]

Introduction. Cement microstructure imaging is an emerging field of non-destructive compositional investigation. Some data may be available via one method but not the other due to various physical and chemical mechanisms that could cause cement decay. In order to quantitatively and qualitatively evaluate cement stone, it is necessary to investigate it as a complex multi-phase composite material, identify its crystalline phases, and estimate the precise size of its nanoparticles. Materials and methods. This work presents the results of a microscopic study of the effect of Nanozeolites (particle size ≤ 100 nm) on cements for cementing wells. To study the surface properties (chemical bonds between molecules, analysis of mineral composition, and surface topography and morphology) of class G cement stone, three types of microscopes – IR spectrum, X-ray diffraction (XRD), and atomic force microscopy (AFM) – were used. Zeolite nanoparticle additives were introduced at varying concentrations (0.5%, 1%, 1.5% by weight of cement) after 8 hours of curing in a water bath at atmospheric pressure and a heating temperature of 60оC (140оF). Results and discussion. The infrared spectra revealed changes in surface properties, indicating a decrease in free water and an increase in the strength of the system with the addition of nano zeolite. X-ray diffraction method (XRD) allowed for the identification of the main phases of crystalline hydration. The highest peak intensity is due to calcium hydroxide CH, which decreases with the addition of nano zeolite. This phenomenon elucidates the pozzolanic behavior of nano zeolite, which reacts with precipitated calcium hydroxide upon hydration to form C–S–H, reduces the calcium hydroxide content of the layered structure and increases C–S–H. The topography and surface morphology of the samples were studied at the nanoscale using atomic force microscopy. The images show the nanoparticles propagate along the cracks and appear to increase the surface layer's resistance to deformation and stress relaxation in cement-based materials. In addition, they promote viscoelastic C–S–H behavior. Conclusion. Adding nano zeolite to Portland cement affects the process of early hydration of cement stone and increases its early strength. Additionally, the introduction of 1.5% nano zeolite into cement results in the formation of irregular peaks and valleys of low porosity filler, ultimately enhancing the cement's strength.

Apatites, being one of the most numerous mineral-like families of compounds, are considered as a matrix for binding lead ions, which is dangerous for the biosphere. The crystal-chemical (composition, structure) and thermophysical aspects (thermal expansion) are considered as the basis for analysing the properties of this kind of material. It is suggested that substances of the composition Pb5(AIVO4)2(BVIO4), Pb5(AIVO4)(CVO4)2 can be a perspective form of lead binding materials based on compounds with the structure of apatite (AIV = Si, Ge; BVI = S, Cr; CV = P). Such compounds, as it was shown by DTA and HTXRD experiments, are distinguished by the absence of polymerphism and the abnormal ordering of structure. Also, they have relatively low values of thermophysical indicators (the rate of change of linear thermal expansion coefficients is 0.02–0.03×106 K-1; values of the volume thermal expansion coefficients are 40–70×106 K-1). Compounds Pb5(SiO4)(PO4)2 (a = 9.78782(16) Å, c = 7.31084(16) Å, V = 606.555(23) Å3, R-bragg = 4.694 %) and Pb5(GeO4)(PO4)2 (a = 9.87697(12) Å, c = 7.33136(11) Å, V = 619.388(17) Å3, R-bragg = 1.730 %) were obtained, identified and crystallographically characterised for the first time.

In this research paper, (C6H9N2)2[CdCl4], was effectively synthesized using the slow solvent evaporation procedure. Single crystal X-ray diffraction (scXRD) analysis revealed that the compound crystallizes in the triclinic system, specifically in the space group P 1¯. Powder XRD (PXRD) of the bulk material showed some minor impurities. The atomic arrangement of the title structure comprises discrete tetrahedral groups [CdCl4]2− linked to the organic entities through weak N(C)H…Cl hydrogen bonds. Solid-state contacts were further studied through Hirshfeld surface analyses, complemented by 2D fingerprint plots. Computational results, obtained using the B3LYP tool with 6-311++G(d,p) + LANL2DZ mixed basis set, demonstrated consistent geometrical, vibrational, and electronic features to the experimental data. Non-covalent interactions were explored in depth using Atoms-In-Molecule (AIM) and Reduced Density Gradient (RDG) analyses. Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC) analyses showed melting at 378 K and decomposition at around 540 K. Furthermore, the inhibition activity of the examined compound was explored in-silico through molecular docking studies targeting the inducible Nitric Oxide Synthase (iNOS) enzymes.

This study finds the equilibrium configuration, vibrational analysis, thermodynamic properties, and electronic properties of formaldehyde and its derivatives, namely acetone, acetyl chloride, and methyl acetate, using First Principles Analysis. It emphasizes the impact of substituents on the carbonyl group and the need for this comprehensive analysis. The computational methods employed in this work are Gaussian DFT), GaussSum and Moltran calculations. For formaldehyde, the optimization step starts from the energy of -114.51282 Hartree and gets optimized in the energy -114.5129634 Hartree. Similarly for Acetone, Acetyl chloride and Methyl acetate, optimization step start from -193.74375 Hartree, -613.26 Hartree, -266.805 Hartree and gets optimized in the energy -193.1744033 Hartree, -613.2941798 Hartree, -266.8358066 Hartree. Infrared (IR) spectroscopy is used to analyze vibrational frequencies. The C-H and C=O vibrations are highlighted, showing characteristic peaks for each compound. Heat capacity at constant volume (Cv), heat capacity at constant pressure (Cp), internal energy (U), enthalpy (H), entropy (S) and Gibb’s free energy (G) with change in temperature sharply increase from 10 K to 50 K and decreases the increase in rate from 50 K to 500 K. In the derivative of Formaldehyde, Methyl Acetate has the highest energy gap (i.e. -7.4222 eV) and Acetyl Chloride has the small energy gap (i.e. 5.6137 eV). The Chemical parameters like ionization potential, electron affinity, chemical hardness, chemical potential, electronegativity, electrophilicity index, and chemical softness have been also calculated. Electrostatic Potential (ESP) Surfaces, Molecular Electrostatic Potential (MEP), and Electron Density (ED) are visualized to understand charge distribution and reactivity regions. DOS spectra illustrate the density of electron states per unit energy.

The results of the synthesis of microcrystalline calcium phosphates such as hydroxoapatite, pyrophosphate, and tricalcium phosphate are presented herein. The influence of the addition of polyvinylpyrrolidone (PVP) on the phase characteristics of the resulting high-temperature ceramic sample is considered. The X-ray results show that hydroxyapatite (HAp) consists of a Ca5(PO4)3(OH) phase, while the sample with the addition of polyvinylpyrrolidone contains β-Ca3(PO4)2 (65.5%) and β-Ca2P2O7 (34.5%) phases calcium phosphates (CPs). IR spectroscopy was used to characterize the compositions of the samples. An important characteristic of the obtained samples is the elemental Ca/P ratio, which was determined via energy-dispersive analysis. The data obtained are consistent with the composition of dental enamel apatites, namely, in the CPs (1.27) and HAp (1.40). SEM was used to study the morphology of the surfaces of hydroxyapatite particles. Polyvinylpyrrolidone polymer fibers were obtained using the electroforming method with the inclusion of CPs in the composition. The fibers were oriented randomly, and nanoscale hydroxyapatite particles were incorporated into the fiber structure. Solubility data of the HAp, CPs, and Fibers in a physiological solution at room temperature and human body temperature were obtained. The solubility of the resulting HAp turned out to be higher than the solubility of the CPs. In turn, the concentration of Ca2+ in a physiological solution of PVP composite fibers with the inclusion of CPs was lower than that in powdered CPs. [ABSTRACT FROM AUTHOR]

Conformational analysis of N,N-dialkylamides of diphenylphosphorylacetic acid has been carried out using the methods of dipole moments, IR spectroscopy, and quantum chemistry DFT B3PW91/6-311++G(df,p), including the CPCM model. In solution, N,N-diethyl-, N,N-dibutyl- and N,N-dioctylamides exist as equilibrium mixture of conformers, in which forms with cis-orientation of phenyl rings and synclinal orientation of the Csp3‒Csp2(C=O) bond relative to the phosphoryl group predominate, the carbonyl group and P‒Csp3 bond being anticlinal. The stabilization of the preferred conformers is facilitated by intramolecular hydrogen contacts and the possible presence of the p,π-conjugation between the phosphoryl group and the phenyl ring in their molecules. [ABSTRACT FROM AUTHOR]

In our previous study, we elaborated a method of determination of concentrations of the basic sites O2− and OH− in a quantitative IR study of CO2 adsorption. Previous adsorption studies or TPD experiments only provided the total basicity without distinguishing between O2− and OH−. In this study, we determined the concentration of O2− and OH− on ZnO, Ga2O3, and MgO surfaces. The basicity of ZnO and MgO was found to be significantly higher than that of Ga2O3. The surface of ZnO was rich in O2−, the contribution of OH− was very small, and the Ga2O3 surface contained mainly OH−. For MgO, the contribution of O2− and OH− was comparable. According to the IR results, only a small fraction of all surface hydroxyls were sufficiently basic to react with CO2. The partial dehydroxylation changed the proportion of the concentrations of O2− and OH− on the oxides. We also elaborated upon a new method to determine the total concentration of basic sites via CO2 desorption monitored using IR. For all the oxides, we studied the sum of the concentrations of O2− and OH−, as determined in our quantitative IR studies, to find whether they were comparable with the total basicity determined in the desorption experiments. [ABSTRACT FROM AUTHOR]

This article, published in the European Journal of Inorganic Chemistry, provides information on the synthesis and characterization of trichlates, which are larger versions of triflates. The crystal structures of two trichlate compounds, NH4[Cl3CSO3] and (NH4)[Cl2CHSO3], are described, along with their properties and thermal analyses. The article also discusses the accidental synthesis of (NH4)[Cl2CHSO3] and the need for a reliable synthesis protocol for the [Cl2CHSO3]− anion. This research aims to contribute to the understanding of trichlates and their comparison to triflates. [Extracted from the article]

The influence of phosphorus substitution of nitrogen in heterocyclic compounds on the vibrational spectroscopy as well as frontier molecular orbitals are analyzed. Nicotine with two nitrogen atoms in its structure is taken as the sample system to be studied computationally. By replacing the nitrogen atom in one or both rings of this molecule with phosphorus, three nicotine derivatives are created. The vibrational circular dichroism and infrared spectra of these four molecules in their monomer state, as well as the assemblies up to trimers are determined. The aforementioned spectra are calculated using static quantum chemical calculations employing a cluster‐weighted approach. The calculated gas phase spectra of nicotine are compared to their respective experimental spectra. It is observed that the nicotine derivatives with phosphorus in the methylpyrrolidine ring have considerably different gas phase and bulk phase vibrational circular dichroism spectra when compared to nicotine. The phosphorus substitution reduces the energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital as well as altering the polarizability and reactivity of the investigated molecules. [ABSTRACT FROM AUTHOR]

Juglone, a quinonic compound present in walnut extracts, was proposed as a restoring agent for hair keratin treated with permanent or discoloration processes. The proposed mechanism of restoration by juglone involves the formation of a Michael adduct between the quinone and the thiol moieties of cysteine residues. To this purpose, the first part of the present paper involved the spectroscopic study of the product of the reaction between juglone and N-acetyl-L-cysteine as a model compound. IR spectroscopy and Scanning Electron Microscopy (SEM) monitored the chemical and morphological variations induced by applying juglone to hair keratin. In order to simulate the most common hair treatments (i.e., permanent and discoloration), juglone was applied to hair that had been previously treated with a reducing agent, i.e., methyl thioglycolate (MT) or with bleaching agents (based on hydrogen peroxide and persulfates) followed by sodium hydrogen sulfite. IR spectroscopy allowed us to monitor the formation of Michael adducts between juglone and cysteine residues: the Michael adducts' content was related to the cysteine content of the samples. In fact, MT and sodium hydrogen sulfite favored the reduction of the disulfide bonds and increased the content of free cysteine residues, which can react with juglone. SEM analyses confirmed the trend observed by IR spectroscopy since hair samples treated with juglone adopted a more regular hair surface and more imbricated scales, thus supporting the possible use of juglone as a restoring agent for damaged hair keratins. [ABSTRACT FROM AUTHOR]

The purpose of the researches is to analyze the chemical nature of new commercial modified fatliquor materials obtained on the basis of sulfonated, sulfated, oxidized natural and synthetic fats, as well as to determine the features of interaction in the "collagen-fatliquor material" system, which will make it possible to predict the behavior of these materials during liquid finishing of leather. Methodology. To achieve this goal, spectral analysis and interpretation of the spectra of modified fatliquor materials were used. As the latter, new products from Smit & Zoon (Netherlands) were studied: Sulphirol EG 60 -- sulfited natural and synthetic fats; Synthol LC -- natural and synthetic fats, sulfated triglycerides, lecithin-containing mixture; Sulphirol C -- oxidized sulfited fats based on marine fish fats. The chemical nature of the analyzed fats and their interaction with gelatin as a collagen model was studied using infrared spectroscopy. The researches were carried out on an infrared spectrometer (FTIR), designed to obtain infrared transmission or reflection spectra of the objects under study. Findings. It has been experimentally established that, due to the presence of various functional groups and bonds, new modified fatliquor materials have a multifunctional nature and can interact with gelatin to form new (hydrogen, electrovalent, covalent, etc.) bonds in its structure. Based on a study of the relative optical density of chrome-plated gelatin films before and after treatment with modified fatliquor materials, it was revealed that sulfur- and phosphorus-containing groups of fats and nitrogen-containing (amine, imine, amide) groups of gelatin take the greatest part in this interaction, its oxygen-containing groups (hydroxyl and carbonyl) are less active) groups. Sulphirol EG 60 sulfited fat and sulfated lecithin-containing Synthol LC exhibit greater activity in interaction with gelatin among the studied fatliquor materials than Sulphirol C fatliquor material synthesized on the basis of oxidized and sulfited marine fish fats. The revealed ability of modified fatliquor materials to interact with gelatin, and therefore with collagen, will contribute to the prevention of their redistribution in the dermis or their removal from it, which will have a positive effect on the stability of the structure and properties of skin and leather products. Originality. The scientific novelty consists in determining the chemical nature of new modified fatliquor materials of various origins, intended for skin treatment, as well as the nature of their interaction with gelatin - a model of collagen, which is the main component of the dermis of the animal skin and natural leather, which is made from it. This will make it possible to explain the peculiarities of transformations in the "collagen-fatliquor material" system during liquid finishing, their influence on the formation of the structure and properties of the leather. Practical value. The results of the work will contribute to the expansion of the assortment and justified use of chemical reagents of the new generation in innovative technologies for the production of leather of the modern assortment. [ABSTRACT FROM AUTHOR]

Tris(hetaryl)substituted phosphines and their chalcogenides are promising polydentate ligands for the design of metal complexes. An experimental and theoretical conformational analysis of tris[2-(4-pyridyl)ethyl]phosphine, tris[2-(2-pyridyl)ethyl]phosphine, and their chalcogenides was carried out by the methods of dipole moments, IR spectroscopy and DFT B3PW91/6-311++G(df,p) calculations. In solution, these compounds exist as an equilibrium of mainly non-eclipsed (synclinal or antiperiplanar) forms with a predominance of a symmetrical conformer having a gauche-orientation of the Csp3–Csp3 bonds of pyridylethyl substituents relative to the P=X bond (X = lone pair, O, S, Se) and a gauche-orientation of the pyridyl rings relative to the zigzag ethylene bridges. Regardless of the presence and nature of the chalcogen atom (oxygen, sulfur, or selenium) in the studied molecules with many axes of internal rotation, steric factors—the different position of the nitrogen atoms in the pyridyl rings and the configuration of ethylene bridges—determine the realization and spatial structure of preferred conformers. [ABSTRACT FROM AUTHOR]

Superelectrophilic anions constitute a special class of molecular anions that show strong binding of weak nucleophiles despite their negative charge. In this study, the binding characteristics of smaller gaseous electrophilic anions of the types [B6X5]− and [B10X9]− (with X=Cl, Br, I) were computationally and experimentally investigated and compared to those of the larger analogues [B12X11]−. The positive charge of vacant boron increases from [B6X5]− via [B10X9]− to [B12X11]−, as evidenced by increasing attachment enthalpies towards typical σ‐donor molecules (noble gases, H2O). However, this behavior is reversed for σ‐donor–π‐acceptor molecules. [B6Cl5]− binds most strongly to N2 and CO, even more strongly than to H2O. Energy decomposition analysis confirms that the orbital interaction is responsible for this opposite trend. The extended transition state natural orbitals for chemical valence method shows that the π‐backdonation order is [B6X5]−>[B10X9]−>[B12X11]−. This predicted order explains the experimentally observed red shifts of the CO and N2 stretching fundamentals compared to those of the unbound molecules, as measured by infrared photodissociation spectroscopy. The strongest red shift is observed for [B6Cl5N2]−: 222 cm−1. Therefore, strong activation of unreactive σ‐donor–π‐acceptor molecules (commonly observed for cationic transition metal complexes) is achieved with metal‐free molecular anions. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Alkenols are important intermediates for the industrial manufacture of various commodities and fine chemicals. At present, alkenols are produced via thermocatalytic semihydrogenation of corresponding alkynols using precious metal Pd‐based catalysts in pressurized hydrogen atmosphere. In this work, we highlight an efficient electrocatalytic strategy for selectively reducing alkynols to alkenols under ambient conditions. Using 2‐methyl‐3‐butyn‐2‐ol as a model alkynol, Cu3P nanoarrays anchored on Cu foam remarkably deliver an industrial‐level partial current density of 0.79 A·cm–2 and a specific selectivity of 98% for 2‐methyl‐3‐buten‐2‐ol in acidic solution. Over a 40‐runs stability test, Cu3P nanoarrays maintain 90% alkynol conversion and 90% alkenol selectivity. Even in a large two‐electrode flow electrolyser, the single‐pass alkynol conversion and alkenol selectivity of Cu3P nanoarrays exceed 90%. Moreover, this selective electrocatalytic hydrogenation approach is broadly feasible for the production of various water‐soluble alkenols. Electrochemical analyses, theoretical simulation and electrochemical in‐situ infrared investigations together reveal that exothermic alkynol hydrogenation, facile alkenol desorption and formation of active H on Cu3P surfaces account for the excellent electrocatalytic performance. [ABSTRACT FROM AUTHOR]

Possibilities of Fourier-transform IR spectroscopy and Fourier-transform IR microscopy with for the structural group and distribution analysis of sedimentary rock samples are presented on an example of oil shale of the Bazhenov formation of the West Siberian oil and gas basin. The results are considered in combination with a set of methods used in the geochemical analysis of rocks, i.e., programmed pyrolysis according to the Rock–Eval procedure, X-ray fluorescence spectrometry, and elemental CHNS/O analysis. It is shown that the IR spectroscopy method can be used for structural group analysis and the estimation of organic matter content directly in oil source rocks. In the studied samples of kerogen-saturated rocks of the Bazhenov formation, the concentration of organic matter is in good agreement with the results of pyrolysis, and the amount of aliphatic fragments exceeds that of aromatic fragments by 2.0–2.3 times, which corresponds to transformed type II kerogen. Fourier-transform IR microscopy, known as a convenient non-destructive method of analysis, also offers a possibility of the distribution analysis of organic matter over the polished surface of a sample using color area mapping. Using samples of the Bazhenov formation as an example, the heterogeneity of the composition of rocks and the uneven distribution of organic matter in unconventional reservoirs was demonstrated; this ensures the effective use of the IR microscopy method in combination with other methods for studying oil source rocks. [ABSTRACT FROM AUTHOR]

Ethoxyamine derivatives of humic acids have been obtained by mechanochemical synthesis via the simultaneous interaction of humic acids with poly(ethylene glycol) (PEG-6000 and PEG-1500) and an aminating reagent (urea, hydroperitum, or cyanoguanidine) in a vibrating apparatus. Reaction products have been characterized by IR spectroscopy, acid–base potentiometric titration, and viscometry. Tensiometric and rheological characteristics of the surface layers of solutions of salts of the synthesized derivatives of humic acids have been studied by the pendant drop and oscillating pendant drop methods. The solutions of the salts of ethoxyaminohumic acids have been found to exhibit a pronounced surface activity at the air–water interface. The experimental dependences of the viscoelastic modulus on the surface pressure and the concentration of the solutions of ethoxyaminohumic acid salts are in satisfactory agreement with the functions calculated in terms of the theoretical model of bimolecular adsorption. The presence of amino groups in the structure of ethoxyaminohumic acids predetermines their high solubility in the acidic pH region. The simultaneous incorporation of ethoxy and amino groups into humic acid macromolecules makes it possible to obtain a novel type of surfactants, which combine three functions, i.e., the functions of anionic, cationic, and nonionic surfactants. [ABSTRACT FROM AUTHOR]

Betaines of squaric acid have gained research interest because of their structural and spectral properties. We elucidated the crystal and molecular structure of the triethylammonium betaine of squaric acid (1) by X-ray crystallography, IR, and NMR spectroscopy augmented by Hirshfeld surface analysis and DFT calculations. The crystal structure determination using Hirshfeld atom refinement reveals that the resonance hybrid structure with partial enolate character of the two lateral squaric acid C=O groups describes 1 best. The solid-state supramolecular structure features weak intermolecular C−H···O hydrogen bonds. The number of C=O bands in the IR spectrum in the solid-state is consistent with local C2v symmetry of the squaric acid residue in 1. The 13C NMR signals of this group in solution were assigned based on 2D NMR experiments and computational prediction using the Gauge-Independent Atom Orbital (GIAO) method. The present study provides the first structural characterization of a betaine of squaric acid containing a four-coordinate nitrogen atom directly attached to the four-membered ring. [ABSTRACT FROM AUTHOR]

A methodical approach to quantitative determination of lignin and cellulose in plant materials by mid-infrared FT-IR spectroscopy using the KBr tablet technique was proposed. For the prepared model binary mixtures of pure cellulose and lignin, a direct correlation was established between the concentration and intensity of the analytical absorption bands of lignin (1508–1512 cm–1) and cellulose (1059–1061 cm–1). Based on the obtained intensity–concentration plots, formulas for calculating the lignin and cellulose contents were derived. The proposed method was tested on a wide range of plant biomass samples, including 9 wood samples and 13 samples of agrowaste materials. A good suitability of the method for the quantitative determination of lignin was shown; the experimental results agree with the literature data within 1%. However, the proposed method was not suitable for the determination of cellulose, since it did not take into account the contribution from hemicellulose and extractive substances to the absorption band at 1059–1061 cm–1, which led to strongly overestimated results from the cellulose content determination. [ABSTRACT FROM AUTHOR]

The molecular crystals of monomeric and dimeric pyrazole complexes were prepared via one‐pot syntheses. These are dichloridobis(3,5‐dimethyl‐1H‐pyrazole‐κN1)cobalt/zinc(0.2/0.8), [Co0.20Zn0.80Cl2(C5H8N2)2] or [Co0.2Zn0.8Cl2(3,5‐dmp)2] (1), and bis(μ‐3,5‐dimethyl‐1H‐pyrazole)‐κ2N1:N2;κ2N2:N1‐bis[bromido/chlorido(0.7/0.3)bis(3,5‐dimethyl‐1H‐pyrazole‐κN1)cobalt/zinc(0.1/0.9)], [Co0.20Zn1.80Br1.40Cl0.60(C5H7N2)2(C5H8N2)2] or [Co0.1Zn0.9Br0.7Cl0.3(μ‐3,5‐dmp)(3,5‐dmp)]2 (2). The isolated complexes contain 3,5‐dimethylpyrazole (3,5‐dmp) ligands formed in situ from the decomposition of 1‐hydroxymethyl‐3,5‐dimethylpyrazole. In both isolated complexes, some positional disorder is observed at the metal ions and halogen ligands. The molecular crystals of 1 and 2 are centrosymmetric, with the space groups C2/c and P, respectively. Additionally, in the dinuclear complex, the pyrazole ring has a bridging coordination function with respect to the metal ions. Both complexes have good biological activities against cancer cells. The results of an in vitro cytotoxicity study indicated that compounds 1 and 2 showed significant cytotoxicity for cancer cell lines, including hepatic (HepG2 cells), lung (A549 cells) and colon cancer cells (SW 480 and SW 620). Based on the calculated IC50 values against human cancer cell lines, it was found that both complexes demonstrated potent antiproliferative activity combined with great selectivity towards cancer cells. Complex 2 was a more effective cytotoxic agent which, at the same time, exhibited high cytocompatibility. The obtained data are very encouraging and could be useful for anticancer drug discovery. [ABSTRACT FROM AUTHOR]

The cations of an ordered omphacite from the Tauern window were gradually disordered in piston cylinder experiments at temperatures between 850 and 1150 °C. The samples were examined by X-ray powder diffraction and then investigated using low-temperature calorimetry and IR spectroscopy. The low-temperature heat capacity data were used to obtain the vibrational entropies, and the line broadening of the IR spectra served as a tool to investigate the disordering enthalpy. These data were then used to calculate the configurational entropy as a function of temperature. The vibrational entropy does not change during the cation ordering phase transition from space group C2/c to P2/n at 865 °C but increases with a further temperature increase due to the reduction of short-range order. [ABSTRACT FROM AUTHOR]

ABSTRACT: Introduction. Silicon oxide film coatings have unique properties and are widely used in various industries, including construction. This paper presents the results on the preparation of polyalkylhydroxysiloxane liquid film in the presence of nanoscale particles of metallic bismuth. Methods and materials. Laser ablation method of metallic bismuth in aqueous medium was used to obtain bismuth nanoparticles. The surface of the target was treated with a laser beam at the workstation of an ytterbium pulsed fiber laser are discussed. The particle size and electrokinetic properties of colloidal bismuth sols were determined method by dynamic light scattering. After drying, Bi powder was added to polyalkylhydroxysiloxane liquid. Thin films cured under different heat treatment modes are applied to glass substrates by dipping. The resulting films were characterized by SEM, X-ray phase analysis, and FTIR spectroscopy. Results. In this work, the electrokinetic properties of colloidal bismuth sols are discussed. Laser ablation of a bismuth substrate leads to an increase in electrical conductivity and the appearance of a double electric layer in colloidal sols. The effect of the curing temperature on the properties of the coating is shown. It was found that the content of bismuth nanoparticles in the polyalkylhydroxysiloxane coating (3 wt.%) does not lead to the formation of crystalline phases. At the same time, the composition of the film and the mode of heat treatment affect the short-range order of molecular bonds. Increasing the content of bismuth nanoparticles in the coating of more than 10 wt.% leads to the appearance of microcrystalline phases of bismuth silicates in the system. Conclusion. The results obtained in the course of the study supplement the information about the production of bismuth nanoparticles by laser ablation and are of great importance in the practice of creating composite films

It is known that in order to restrain the process of oxidation of transformer oil, and, accordingly, to extend its service life, an antioxidant additive ionol is added to it. Previously, specialists using the method of chromato-mass spectrometry established the fact of the formation of new phenolic compounds in oil along with the consumption of the inhibitory additive ionol, namely, 2,6-di-tert-butylphenol (2,6-DTBP) and 2, 6-di-tert-p-benzoquinone. These phenolic compounds, as well as ionol, belong to the class of sterically hindered phenols, which, in turn, are able to inhibit the oxidation of oil during its operation in oil-filled transformer equipment, in particular, power transformers and current transformers. This article presents results showing that as ionol is consumed, 2,6-di-tert-butylphenol accumulates in oil from transformers. To the greatest extent, this trend is noticeable for current transformers equipped with air-drying filters (the so-called "free breathing"). The formation of 2,6-DTBP in oil can serve as an indicator of accelerated aging of the oil as a result of its prolonged contact with atmospheric oxygen. Changes in additive concentrations during oil aging are controlled using a new technique developed by us, based on IR spectroscopy.

[Display omitted] The interaction of bimetallic ( Bu t PCP)Pd···(OC)M(CO) 2 Cp (M = Mo, W) complexes with PhSiH 3 leads to an efficient heterolytic splitting of Si–H bond that is a primary step in catalytic hydrosilylation of CO 2. The reaction can be stopped at the formate level in the presence of the above complexes while proceeds further when catalyzed by ( Bu t PCP)PdH. [ABSTRACT FROM AUTHOR]

Relevance. The problem of studying organometallic compounds in carbonized and carbonaceous substances is part of the global problem of the structure of natural materials from plant remains and manifestation of ore genesis in organic sedimentary deposits. This problem covers a number of issues. The most pressing one among them is the form of occurrence of finely dispersed gold in the form of organometallic compounds in metal-bearing coals and shales. This is especially true for large gold deposits of black shale strata. Aim. To study the relationship between sedimentation of organic formations and ore genesis in black shale deposits using the example of the Verninskoe deposit (Patom Highlands, Yakutia). Using the SKAUFV hardware and software complex together with ICP-MS and INAA methods, which allow one to assess the degree of Au concentration in organic matter, to substantiate the possibility of determining organometallic compounds of gold that are significant in the processes of sedimentogenesis, lithogenesis and epigenesis. Methods. IR spectroscopy, instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP-MS). Results. The authors have determined that the SKAUFV hardware and software complex, together with the ICP-MS and INAA methods, makes it possible to establish the role of organic matter in metasomatism and to identify temperature zonality and the associated gold concentration in the ore zone. To determine the organometallic compounds of Au, structural and genetic indicators (Pm, Ko, PVt+L, PI) were selected. These indicators reflect the significance of sedimentation, diagenesis, catagenesis and epigenesis on Au concentration of in organic matter. These indicators made it possible to assess the level of temperature impact on sedimentary deposits of regional metamorphism and near-ore metasomatism. In this regard, subzones of Au concentration were established in the ore zone, determined by temperature zoning in the form of a manifestation of local metasomatism. The latter was influenced by the protein-fat composition of plants that form organic matter.

FTIR spectroscopy method of a single frustrated total internal reflection was used to study 53 samples of coniferous wood and 77 samples of deciduous wood of the middle zone of Russia. Characteristic absorption bands in IR spectra were described, absorption band places characteristic for coniferous and deciduous wood were revealed. Characteristic differences in the spectra of coniferous and deciduous wood species suitable for their identification were determined. Using the established characteristic differences, the wood species of three archaeological materials were identified. The results of approbation of the previously proposed method of identification of archaeological wood species by IR spectroscopy of a single frustrated total internal reflection were presented. It is shown that the most promising diapason for identification species of archaeological wood samples is 1270-1220 cm-1, where two bands of different intensity were detected. In the spectra of coniferous wood the more intensive band is located in about 1265 cm-1 and in the spectra of deciduous species – about 1230 cm-1.

This work aimed to describe the synthesis and characterisation of two anionic Ru(III) complexes of the general formula Na[RuCl2(N-4-Cl-Ph-salim)2] and Na[RuCl2(N-3-Br-Ph-salim)2, their associated ligands, and determine their antioxidant activity. The ligands N-4-Cl-phenylsalicylidenimine (N-4-Cl-Ph-salimH, HLa) and N-3-Br-phenylsalicylidenimine (N-3-Br-Ph-salimH, HLb), Schiff bases, were synthesised from salicylaldehyde and chloroaniline or bromoaniline. The compounds were characterised using IR spectroscopy and ESI ToF mass spectrometry. The following was confirmed: coordination of ligands on the Ru(III) centre, the molecular formulas, and the corresponding M– ions: [C26H18N2O2Cl4Ru]− ion, (m/z: 631.9173) and [C26H18N2O2Cl2Br2Ru]– ion, (m/z: 719.8283). The antioxidant activity was determined by the ABTS (2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and DPPH (1,1-diphenyl-2-picrylhydrazyl) assays. In contrast to the ligands, both complexes proved to be strong scavengers of the ABTS and DPPH radicals with IC50 (half maximal inhibitory concentration) values comparable to those of Trolox. As such, they present valuable candidates for further research related to their biological properties.

New data on the crystal structure and isomorphism of extra-framework components in the cancrinite-group mineral tounkite have been obtained using chemical and single-crystal X-ray diffraction data, as well as infrared, Raman, ESR, UV–Vis–near-IR absorption and photoluminescence spectroscopy methods. The crystal structure of tounkite is based on the aluminosilicate framework formed by the САСАСВСВСАСВ stacking sequence with ordered Si and Al atoms The framework hosts Losod and liottite cages as well as columns of cancrinite cages. It is shown that tounkite is characterized by wide variations of the chemical composition. Its simplified crystal–chemical formula is (Na+3.89–5.18K+0.15–1.64Ca2+2.30–2.58(Al6Si6O24)(SO42−,S52−,S4) 2−x (Cl−, HS−)1+y·nH2O (x, y, n < 1). The S2⦁− and S3⦁− radical anions may occur in some tounkite samples in minor amounts. These crystal–chemical features indicate that tounkite crystallizes under highly reducing conditions. All studied tounkite samples were polysynthetic twins. A large 10-layed cage formed at the border between twin components, connected by a rotation of 180° around the [001] axis, which may host the large S52− anion.

In our study, we investigated the accelerated aging process of PLA under 253.7 nm UV-C irradiation with the use of the GPC, NMR, FTIR, and DSC methods and formal kinetic analysis. The results of GPC and DSC indicated a significant degree of destructive changes in the PLA macromolecules, while spectroscopic methods NMR and FTIR showed maintenance of the PLA main structural elements even after a long time of UV exposure. In addition to that, the GPC method displayed the formation of a high molecular weight fraction starting from 24 h of irradiation, and an increase in its content after 144 h of irradiation. It has been shown for the first time that a distinctive feature of prolonged UV exposure is the occurrence of intra- and intermolecular radical recombination reactions, leading to the formation of a high molecular weight fraction of PLA decomposition products. This causes the observed slowdown of the photolysis process. It was concluded that photolysis of PLA is a complex physicochemical process, the mechanism of which depends on morphological changes in the solid phase of the polymer under UV radiation.

It was shown by IR spectroscopy that the mechanism of formation of titanium dioxide (TiO2) tubulenes during the mechanochemical activation of nanodispersed hydrated TiO2 under the conditions of high contact pressure includes a stage of aggregation of the TiO2 particles through the formation of Ti–O–Ti bridges. During further mechanical action the oxide blocks are transformed into two-dimensional crystalline structures with the formation of tubulenes. [ABSTRACT FROM AUTHOR]

The aim of this work is to highlight the influence of UV light on the hydrolysis reaction of nifedipine (NIF) in the presence of alkaline solutions. In this context, the photodegradation of NIF in the absence of alkaline solutions caused (a) a change in the ratio between the absorbances of three bands in the UV-VIS spectra localized at 224–240 nm, 272–276 nm and 310–340 nm, assigned to the electronic transitions of -COOCH3 groups, -NO2 groups and a heterocycle with six atoms; (b) a red-shift of the photoluminescence (PL) band from 458 nm to 477 nm, simultaneous with an increase in its intensity; (c) a decrease in the ratio of the Raman line intensities, which peaked at 1224 cm−1 and 1649 cm−1, associated with the vibrational modes of -C-C-O in the ester group and C=C stretching; and (d) a decrease in the ratio between the absorbances of the IR bands, which peaked at 1493 cm−1 and 1223 cm−1, associated with the vibrational modes of the -NO2 group and C-N stretching. These changes were explained considering the NIF photodegradation reaction, which leads to the generation of the compound 4-(2-nitrosophenyl)-2.6-dimethyl-3.5-dimethoxy carbonyl pyridine. The interaction of NIF with NaOH in the absence of UV light was demonstrated to induce changes in the vibrational mode of the -C-C-O bond in the ester group. The photodegradation of NIF after its reaction with NaOH induces significant changes highlighted in its (a) UV-VIS spectra, by the shift of the absorption band at 238 nm; (b) PL spectra, by the supraunitary value of the ratio between the emission band intensities at 394–396 nm and 450 nm; (c) Raman spectra, by the change in the ratio between the intensities of the lines that peaked at 1224 cm−1 and 1649 cm−1 from 0.61 to 0.49; and (d) FTIR spectra, by the lowered absorbance of the IR band at 1493 cm−1 assigned to the vibrational mode of the -NO2 group as a result of the generation of the nitroso compound. These changes were explained considering the hydrolysis reaction products of NIF, as the nitroso compound is converted to a lactam-type compound. The photodegradation reaction rate constants of NIF and NIF after interaction with NaOH were also reported. The decrease in thermal stability of NIF samples after interaction with NaOH, as well as of NIF after exposure to UV light compared to NIF prior to exposure to UV light, was demonstrated by thermogravimetry, and the key fragments were confirmed by mass spectrometry. [ABSTRACT FROM AUTHOR]

The result of a complex mineralogical study of the first discovery of the rare hydrated magnesium carbonate minerals of Nesquehonite and Dypingite in the Obnazhennaya kimberlite pipe (of the Yakutian kimberlite province) is presented. The methods of X-ray phase analysis, electronic microscopy, and Raman spectroscopy have established that the main minerals of the samples found in the form of white crust on a small area of rock outcrop of kimberlite breccia are hydrated carbonates: Nesquehonite is MgCO3•3H2O, Dypingite is Mg5(CO3)4(OH)2•5H2O. The formation of Dypingite over Nesquehonite was shown using Raman imaging for the first time. Nesquehonite is represented as aggregates consisting of chaotically oriented prismatic crystals or kidney-shaped formations. Dypingite in the examined samples appears less frequently as rose-shaped aggregates formed from lamellar crystals. It is assumed that the formation of rare carbonates of the Obnazhennaya kimberlite pipe is mainly the result of the weathering of silicates, formation of mineralized solutions, and their subsequent crystallization, including the capture of CO2 from the air. [ABSTRACT FROM AUTHOR]

In this study 6-aminopyrimidine-2,4,5(3)-trione-5-[(phenyl)hydrazone] (dye 1) and 6-aminopyrimidine-2,4,5(3)-trione-5-[(4-methoxyphenyl)hydrazone] (dye 2) were resynthesized by method given in the literature and confirmed structurally using Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (1H NMR) spectroscopic methods. For the first time, for dyes 1 and 2, both theoretical studies were performed and investigated in terms of antiparasitic activity. The density functional theory (DFT) calculations for possible tautomeric forms of dyes 1 and 2 were carried out by using DFT/B3LYP/6-311++G (d,p) method. Thus, optimized geometries, IR and 1H NMR spectral data were obtained and compared with experimental ones. Therefore, the most possible tautomeric forms were determined for dyes 1 and 2. Results show that in the gas phase and dimethyl sulfoxide (DMSO) solvent for both dyes, the amine-diketo-hydrazone forms (T-I-H) are the lowest energy and therefore the most stable form. Leishmania spp. and Trichomonas vaginalis are flagellated protozoan parasites that cause parasitic infections in humans. In vitro antiparasitic activity of dye 1 and dye 2 against Trichomonas vaginalis trophozoites, Leishmania tropica, Leishmania major, and Leishmania infantum promastigotes were determined for the first time. The in vitro antileishmanial and antitrichomonal activity was performed by microdilution method. Amphotericin B and Metronidazole were used for Leishmania spp. promastigotes, and T. vaginalis trophozoites, as a control drug, respectively. The Minimum Lethal Concentration (MLC) was determined and compared with the control. [ABSTRACT FROM AUTHOR]

In the present study, colored compounds with an apatite structure of compositions Sr 5 (P x V y Cr z O 4) 3 F (x + y + z = 1.0) were synthesized using a solid-state method. All compounds, except when z = 0.0, were colored in different shades of green. P5+ and V5+ ions are not coloring ions, so the color varied depending on the amount of Cr5+. A comprehensive analysis of the structures of the newly synthesized ternary solid solutions was conducted, and the crystallographic boundaries of the isomorphous mixture were refined. The reliability factors obtained from the refinement demonstrate that the ternary solid solutions crystallize in a hexagonal symmetry, space group P 6 3 / m. The pentavalent P, V, and Cr ions occupied equivalent tetrahedrally coordinated positions in the structure. The bond lengths in the tetrahedral positions are distorted more as the content of the pentavalent ion with a larger radius increases. The conducted comprehensive investigation (crystal structure, infrared spectroscopy, color measurements) of the colored compounds with an apatite mineral structure of compositions Sr 5 (P x V y Cr z O 4) 3 F (x, y, z = 0.0 to 1.0) opens up new possibilities for the development of alternative pigments and expands the application range of pigments based on similar materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: Multidrug regimens can increase the risk of drug–drug interactions at the level of albumin binding especially for drugs with narrow therapeutic windows such as carbamazepine (CBZ). This risk is particularly heightened for CBZ which is mainly metabolized to the active carbamazepine-10,11-epoxide (CBZE) that has been identified as contributory to both the therapeutic efficacy and severity of toxicity in CBZ-treated individuals. The objective of this study was to investigate the binding affinities of albumin with CBZ and CBZE, and to explore the influence of two competing over-the-counter medicines on the binding characteristics. CBZE was synthesized by epoxidation of CBZ and characterized using IR, NMR and mass spectrometry. The influence of paracetamol and ascorbic acid on the albumin complexes of CBZ and CBZE was investigated using absorption and IR spectrophotometry. Results: Protein–ligand complexation produced progressive hyperchromic changes in 278 nm band of bovine serum albumin (BSA) with formation constants of 10.28–10.44 and 12.66–13.02 M−1 for CBZ and CBZE, respectively. Thermodynamic considerations confirmed both binding processes as endothermic, spontaneous and driven by hydrophobic interactions. The presence of ascorbic acid increased the binding constants of both CBZ-BSA and CBZE-BSA complexes by non-competitive interference mechanism. Similarly, paracetamol increased the affinity of CBZ for albumin but then competitively interfered with the CBZE-BSA complex. The ratio of albumin binding affinities of CBZ–CBZE varied from 0.81 in the absence of competing drug to 1.29 and 1.0 with paracetamol and ascorbic acid, respectively. IR study confirmed that both CBZ and CBZE induced a reduction from the 67.34% α-helical content of free BSA to 42.56 and 56.43%, respectively. Competitive binding in the presence of either paracetamol or ascorbic acid induced further reduction in the α-helical content of BSA in the complexes. The most extensive perturbation in the secondary structure of BSA (22.78% α-helical content) which was observed with CBZE-BSA complex in the presence of paracetamol is probably due to the increased interaction of the protein for the analgesic. Conclusion: The study has revealed potential interference of paracetamol or ascorbic acid with the albumin binding of carbamazepine and its major metabolite. [ABSTRACT FROM AUTHOR]

The object of research is ash microspheres from the burning of hard coal in Donetsk, Lviv-Volyn (Ukraine) and foreign (South Africa) basins, power plants of various regions. The chemical and mineralogical composition of Ukrainian ash microspheres was analyzed in comparison with foreign counterparts (South Africa, Great Britain, etc.), other types of microspheres (glass, ceramic) and expanded perlite. The advantages of aluminosilicate microspheres of technogenic origin (ASM) over other lightweight fillers are noted. One of the most problematic areas is the lack of an objective comparative assessment of Ukrainian ash microspheres in terms of the influence of the structure-forming bonds Si–O, Si–O–Si and Si–O–Al on the physicochemical properties and energy and reactivity of their surface. It was established that the SiO2/Al2O3 ratio in their composition is within 1.46–1.87 against 1.53–1.64 in South African ASM and 4.81–5.61 in swollen pearlites, which ensures the content of crystalline phases (mullite, quartz) from 36 wt. % in Trypil microspheres to 53 wt. % in Kurakhove microspheres. The latter have a minimal content of Si–O–Si bonds (the I0/I ratio in the 1029 cm–1 band is 1.25 versus 6.71 in Burstyn ASM). The revealed features of changes in the chemical and mineralogical composition of microspheres, as well as structure-forming bonds, are fully correlated with the content of adsorbed water and OH and CH groups in the surface layer of the latter and, as a result, the energy state and reactivity of ASM. A quantitative assessment of their wettability with water (0.32–0.106) and under the condition of tgδ (0.196–0.4490) is given. The availability of such information makes it possible to clearly classify Ukrainian ash microspheres according to the degree of efficiency of use, taking into account their advantages in the composition of composite materials on various types of binders and to assess the presence of interchangeability in the context of a special situation in Ukraine. [ABSTRACT FROM AUTHOR]

Using the methods of nanosecond laser ablation in isopropyl alcohol and dry grinding of germanium, germanium nanoparticles were obtained for their possible application in liquid high-index immersion. Structural, chemical, and optical characterization of colloidal nanoparticles was carried out using scanning electron microscopy, IR spectroscopy, and energy-dispersive X-ray spectroscopy. [ABSTRACT FROM AUTHOR]

The effect of adsorption of acid gases CO2, SO2, and SO3 on the electron accepting ability of cations on the surface of calcium oxide was studied by low-temperature IR spectroscopy of adsorbed CO. It is shown that the formation of carbonate, sulfite and sulfate anions in the surface layer leads to the appearance of Lewis acid sites, the strength of which, estimated by the shift in the vibration frequency of CO molecules associated with them, increases in the appropriate order, approaching that for calcium-containing zeolites. The results of the calculation of cluster models by the DFT method confirm the observed trends in the variation of the vibrational frequency and the absorption coefficient of CO molecules bound through both the carbon and oxygen atoms, and also demonstrate the dependence of the ability of a cation for CO linkage isomerism on its local environment. [ABSTRACT FROM AUTHOR]

Silicas of MCM-41-type with reactive functional groups are widely used as starting substrates in large variety of post-synthetic chemical modification pathways. Therefore, variation of their structural characteristics in the process of templated sol-gel synthesis or post-synthetic treatment is of great importance. The aim of this work was to elucidate the influence of template agent selection on structural features of MCM-41-type materials with surface silanol and 3-chloropropyl groups. For this purpose, template-assisted sol-gel condensation of structure forming silanes (tetraethyl orthosilicate and 3-chloropropyltriethoxysilane) was carried out in the presence of decyltrimethylammonium bromide as structure-directing agent. The capability of cyclic oligosaccharide (β-cyclodextrin) to interact with surfactant micelles in the process of hydrothermal sol-gel synthesis and to influence the formation of mesoporous structure of silica materials was studied. The IR spectroscopy was applied to carry out control under the complete removal of template moieties from pores by extraction procedure and to confirm introduction of 3-chloropropyl groups into the surface layer of synthesized silicas. Arrangement of mesoscale pores and structural parameters were estimated from the results of X-ray diffraction and low-temperature adsorptiondesorption of nitrogen. It has been found that β-cyclodextrin as component of hybrid template has positive effect on porous structure of 3-chloropropyl-functionalized MCM-41-type silica causing increase of surface area accompanied with preservation of pore ordering. Moreover, both ionic surfactant and oligosaccharide components of hybrid template act as porogens during sol-gel condensation of structure forming silanes enable to prepare silica materials with micro-mesoporosity. Proposed approach can be useful in synthesis of MCM-41-type silicas with surface linker groups and controlled structural characteristics (pore size, geometry and ordering), which have great potential as substrates in design of sophisticated materials. [ABSTRACT FROM AUTHOR]