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The crystal structure of sodium tricyanomethanide Na[C(CN)3] has been confirmed by Rietveld refinement of X-ray powder diffraction data. Additionally, Raman and IR spectra of the title compound have been recorded exhibiting spectra in good agreement with those of other tricyanomethanides. Despite Na[C(CN)3] and K[C(CN)3] crystallizing both in the triclinic space group P 1 ‾ $\overline{1}$ (no. 2), with seemingly similar unit cell parameters, it is demonstrated that they are clearly not isotypic compounds. [ABSTRACT FROM AUTHOR]

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Samples of propyne trapped in solid parahydrogen show multiple peak structures in their infrared spectra. These structures are attributed to molecules in two distinct kinds of matrix sites. The most intense lines are assigned to propyne molecules executing a slightly hindered methyl rotation, as was extensively studied in our earlier publication from our two groups, and the other set of peaks to propyne trapped in a secondary site where the methyl rotation is quenched and replaced by methyl torsion within the matrix site. The assignment of the various rovibrational transitions is made possible by the observation of nuclear spin conversion (NSC) within the methyl group at long timescales. The NSC rate depends on the site and is much slower in the sites where the methyl rotation is quenched. [ABSTRACT FROM AUTHOR]

In this paper, a study of monocalcium phosphate production based on extractable phosphoric acid obtained from Central Kyzyl-Kum phosphorites was conducted. Effects of various parameters (density, temperature, and viscosity of starting materials) on the process of defluoridation and desulfation of extraction phosphoric acid and production of monocalcium phosphate based on calcium carbonate were studied. The experiments were mainly conducted on two samples, and the composition of the substances before and after the process was studied. According to the results, the contents of other components also increase proportionally (sample 1). Thus, the content of calcium oxide increases from 1.58% to 5.54% with a content of 60% P2O5, magnesium from 0.49% to 1.15%, iron oxide from 0.25% to 0.85%, aluminum oxide from 0.38% to 1.24%, sulfate ions from 0.23% to 0.76%, the content of calcium oxide increases from 2.09% to 7.40% with a content of 60% P2O5, magnesium from 0.80% to 2.83%, iron oxide from 0.25% to 0.90%, aluminum oxide from 0.38% to 1.34%, sulfate ions from 0.23% to 0.82%. The fluorine content decreases from 0.32% to 0.17% depending on the EPA concentration (sample 2). Some factors, such as the rate and concentration of phosphoric acid and high-speed separation of phosphoric acid, were also studied in the process of obtaining monocalcium phosphate and its chemical composition and properties. The results obtained based on both samples were studied and analyzed using X-ray, IR spectrum, scanning electron microscopic, and elemental analysis.

Background and Objectives: Manifestations of intermolecular interaction based on hydrogen bonding in hyaluronic acid IR spectra and in multicomponent mixtures of hyaluronic acid with nitrogen-containing amino acids, which are part of mucin of the mucous membrane of the bladder and protein carrier microgels, have been studied using experimental and theoretical IR spectroscopy. Materials and Methods: Comparison of measured and calculated hyaluronic acid IR spectra in harmonic approximation is performed. Calculations of molecular complexes structure and their corresponding IR spectra were carried out, followed by an analysis of the parameters of the hydrogen bonds formed. Results: Estimates of hyaluronic acid complexation with amino acids strength, which are part of protein microgels used in targeted therapy, and in target cells proteins were given. Conclusion: It has been found that the presence of an additional protein structure significantly increases the hyaluronic acid interaction with mucous membrane mucin protein due to intermolecular complexation based on polar basic amino acids.

In this article, the optimal conditions for synthesizing a new flame retardant based on pentaerythritol, phosphoric acid, and magnesium hydroxide are studied. In this case, the molar ratio of the initial substances was 3.64:1, and the synthesis duration was four hours. After the completion of this process, different (1, 3, and 5%) solutions of magnesium hydroxide were added at a temperature of 90 ºC for 3 hours. The yield of this reaction was 85%. Applying this obtained flame retardant to textile materials increases the fire resistance of textile materials. The composition of synthesized antiperine and antiperine applied textile fabrics was studied by IR spectrum, and the thermal decomposition of antiperine applied fabric was investigated by TGA and DTA analysis, and 100 μm sections of flame retardant treated fabrics were measured by scanning electron microscope. The fire resistance and physical mechanical properties of these materials were studied based on the requirements of GOST 50810-95. The oxygen index of the fabric treated with synthesized flame retardant was 35.6%. [ABSTRACT FROM AUTHOR]

Structural dynamic models of magnesium glycinate and magnesium tyrosinate complexes were simulated by the method of density-functional theory (DFT) using the B3LYP functional in the 6-31G(d,p) and 6-31G basis sets. The molecular geometric parameters and frequencies of normal vibrations within the harmonic approximation in the IR spectra of the developed models were calculated. Magnesium(II) complexes with glycine and tyrosine were synthesized from aqueous solutions of the corresponding salts of magnesium chloride and the amino acid. The content of amino acids in the synthesized compounds was determined by formol titration using the Sørensen method. The content of magnesium(II) ions is determined by complexometric titration. The IR spectra of the synthesized compounds were recorded in the range of 500–4000 cm–1. The calculated and experimental IR spectra of the synthesized magnesium(II) complexes with glycine and tyrosine were compared in order to validate their structures. Data on the coordination of calcium and magnesium ion complexes with amino acids contributes to understanding the structure of these poorly studied complexes and improving methods for obtaining these complex compounds with a predetermined composition and structure. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HAP) structures with cationic substitutions are studied. Paper presents results obtained using DFT calculations for Mg/Ca substitutions in HAP depending on Mg concentration. Data obtained showed agreement with the experiment: the lattice parameters decreased with increase in Mg concentration. A symmetry violation was found upon the Mg/Ca substitution in the Ca2 position compared to the Ca1 position, due to OH distortion and the Mg-O pair shift relative to OH channel axis. The change in piezoelectric coefficients upon these Mg/Ca2 substitutions was higher by a factor of 1.5 than those of Mg/Ca1. The corresponding changes was in the IR spectrum. [ABSTRACT FROM AUTHOR]

The title compound, [Co(NCS)2(C6H7NO)]n or Co(NCS)2(2-methylpyridine N-oxide), was prepared by the reaction of Co(NCS)2 and 2-methylpyridine N-oxide in methanol. All crystals obtained by this procedure show reticular pseudo-merohedric twinning, but after recrystallization, one crystal was found that had a minor component with only a very few overlapping reflections. The asymmetric unit consists of one CoII cation, two thiocyanate anions and one 2-methylpyridine N-oxide coligand in general positions. The CoII cations are octahedrally coordinated by two O-bonding 2-methylpyridine N-oxide ligands, as well as two S- and two N-bonding thiocyanate anions, and are connected via μ-1,3(N,S)-bridging thiocyanate anions into chains that are linked by μ-1,1(O,O) bridging coligands into layers. No pronounced directional intermolecular interactions are observed between the layers. The 2-methylpyridine coligand is disordered over two orientations and was refined using a split model with restraints. Powder X-ray diffraction (PXRD) indicates that a pure sample was obtained and IR spectroscopy confirms that bridging thiocyanate anions are present. Thermogravimetry and differential thermoanalysis (TG-DTA) shows one poorly resolved mass loss in the TG curve that is accompanied by an exothermic and an endothermic signal in the DTA curve, which indicate the decomposition of the 2-methylpyridine N-oxide coligands.

Investigation of inulin and the possibilities of its use is a relevant and important scientific and practical task. The goal is to study the features of the structural organization of inulin and analyze the possibilities of its use. The object and methods of the research. The object of the research was inulin obtained from Jerusalem artichoke roots. Photography (macro photography) was carried out using a SONY NEX-5N camera (Thailand). The microstructure was studied using an Olympus CX41RF light microscope (magnification 40, 100 and 400 times), ALTRA 20 Soft Imaging Sistem camera (Japan). IR absorption spectra were recorded on a Perkin Elmer Spectrum 1000 single-beam Fourier spectrometer in the spectral range of 400–4000 cm–1 with a spectral slit width of 4 cm–1; the recording time for one spectrum was about 2 min. The literature search on the problem was carried out in the databases of RSCI, Google Scholar, ResearchGate, PubMed using keywords and phrases: «inulin», «inulin structure», «inulin properties», «use of inulin», «fructo-oligosaccharides».The results and their discussion. Analysis of the IR spectrum has confirmed that inulin is a polysaccharide consisting of fructose residues. Studies of the morphology of inulin using light microscopy have shown that inulin is organized in the form of pseudocrystalline formations. In a medium of 96% ethyl alcohol, the central (in the form of a dark circle) and peripheral parts (in the form of a translucent circle that envelops the central dark circle), as well as small parts of inulin (in the form of dark dots) separating from the main pseudocrystalline formations, are clearly visible. There is a wide variety of foods fortified with inulin. It has been established that inulin concentrations used for food fortification vary widely depending on the type of food product, ranging from 0.75 to 50%. The prebiotic effect of inulin has been proved, but its interaction with various food matrices is a complex process, and it is not always technologically beneficial for the product. In addition to sensory, physicochemical and rheological characteristics, it is also necessary to measure characteristics such as prebiotic content of foods and determine prebiotic activity in vivo and in vitro, as well as evaluate potential adverse reactions in order to determine scientifically based doses of inulin for consumers.Conclusion. The obtained IR spectrum confirms the known chemical structure of inulin. Morphological studies of inulin using light microscopy indicate the creation of pseudocrystalline formations by inulin in a medium of glycerol and 96% ethyl alcohol. Inulin can be widely used in various foods as an important biologically active substance.

The reaction of iron thiocyanate with 3-cyanopyridine (C6H4N2) leads to the formation of two compounds with the composition [Fe(NCS)2(C6H4N2)4] (1) and [Fe(NCS)2(C6H4N2)2(H2O)2]·2C6H4N2 (2). The asymmetric unit of 1 consists of one iron cation, two thiocyanate anions and four 3-cyanopyridine ligands in general positions. The iron cation is octahedrally coordinated by two N-bonded thiocyanate anions and four 3-cyanopyridine ligands. The complexes are arranged in columns along the crystallographic c-axis direction and are linked by weak C—H...N interactions. In 2, the asymmetric unit consists of one iron cation on a center of inversion as well as one thiocyanate anion, one 3-cyanopyridine ligand, one water ligand and one 3-cyanopyridine solvate molecule in general positions. The iron cation is octahedrally coordinated by two N-bonded thiocyanate anions, two cyanopyridine ligands and two water ligands. O—H...N and C—H...S hydrogen bonding is observed between the water ligands and the solvent 3-cyanopyridine molecules. In the crystal structure, alternating layers of the iron complexes and the solvated 3-cyanopyridine molecules are observed. Powder X-ray (PXRD) investigations reveal that both compounds were obtained as pure phases and from IR spectroscopic measurements conclusions on the coordination mode of the thiocanate anions and the cyanogroup were made. Thermogravimetric (TG) and differential thermoanalysis (DTA) of 1 indicate the formation of a compound with the composition {[Fe(NCS)2]3(C6H4N2)4}n that is isotypic to the corresponding Cd compound already reported in the literature. TG/DTA of 2 show several mass losses. The first mass loss corresponds to the removal of the two water ligands leading to the formation of 1, which transforms into {[Fe(NCS)2]3(C6H4N2)4}n, upon further heating.

Background and Objectives: This work is devoted to the study of the influence of moisture of alabaster (building plaster) samples on the profiles of their IR spectra in the wave number range of 500–4000 cm−1. Materials and Methods: IR spectra of distilled water and alabaster samples with the moisture of 0, 26, 106, 132, 159, 185 and 212% at 23°C were investigated by experimental methods of disturbed total internal reflection. Wave numbers and intensities of components of IR spectra of CaSO4(H2O)n clusters for 0

The purpose of this study is to reveal the adsorption mechanism of oxygen molecules on gold clusters. density functional theory is employed to investigate the low-energy structure of multiple O2 adsorption on the Au10+ cluster and findings are compared with IR spectra. The nature of bonding of the O2 molecule and Au10+ cluster has been characterised through several metrics like binding energy, dissociation energy, bond length, and vibrational frequencies. The result shows that the lowest-energy structures are prism-shaped rather than tetrahedron-shaped, where only one O2 is chemically adsorbed while others are physically adsorbed. Chemically adsorbed η2-O2 behaves like free O2–, forming a single electron π bond with Au10+, while physically adsorbed η1-O2 does not result in an effective chemical bond and behaves like free O2. This study provides insights into the mechanism of oxygen molecule adsorption on gold clusters and can contribute to further research on the catalytic mechanism of gold clusters. Highlights Lowest energy structures are prism-shaped rather than tetrahedron-shaped, which is supported by IR spectrum and chemical hardness. Chemically adsorbed O2 is activated and displays structural and spectral features of free O2–, while physically adsorbed O2 is close to free O2 in vibrational frequency and bond length. Chemical adsorption is equivalent to a single electron π bond while physical adsorption forms no effective chemical bond due to the lack of electronic pairing between Au10+ and O2. [ABSTRACT FROM AUTHOR]

In order to explored the effects of different vegetation coverage on soil humus in Chagan Lake wetland, taking Chagan Lake wetland as the research object, from the perspective of the response relationship between soil environment and plants, the changes of soil humus carbon content and its infrared spectral structure characteristics of different profiles and five different vegetation types (reed + cattail, reed + moss, calymphus, paspalum, reed) were analyzed. The results show that the contents of humus carbon, humic acid carbon and fulvic acid carbon in the deep layer are larger than those in the shallow layer, and the contents of humin carbon are much smaller than those in the humic acid carbon and fulvic acid carbon. The soil depth has significant effect on the humus components, and the humus carbon content in the soil of different vegetation shows a trend of reed > paspalum > calcareous grass > reed cattail > reed moss. Humic acid and fulvic acid have similar chemical structure and same functional groups in different vegetation soils. The results of the study have certain theoretical and practical significance to reveal the formation and transformation of soil humus in saline-alkali wetland, and provide basic data and scientific guidance for soil environment restoration and screening of dominant vegetation in Chagan Lake saline-alkali wetland. [ABSTRACT FROM AUTHOR]

The work is aimed at the development of an energy-saving technique involving the partial carboxylation of powdered lignocellulose products from the straw of annual agricultural plants and the use of the obtained products in rubber compositions as a water-swelling filler. Lignocellulose powder from oat straw (composition: α-cellulose—77.0%, lignin—3.8%, resins and fats—1.8%) was used for carboxylation without preliminary separation into components. Microwave radiation was used to activate the carboxylation process. This reduced the reaction time by 2–3 times. The synthesized products were analyzed by IR spectroscopy, thermogravimetry and scanning electron microscopy. Industrial product sodium carboxymethylcellulose (Na-CMC) was used as a swelling filler for comparison. The swelling fillers were fractionated by the sieve method; particles with the size of 0–1 mm were used for filling rubber compounds. The amount of swelling filler was 150 parts per 100 parts of rubber (phr). Due to the high filling of rubber compounds, plasticizer Oxal T-92 was added to the composition of a number of samples to facilitate the processing and uniform distribution of ingredients. The rubber composition was prepared in two stages. In the first stage, ingredients without swelling filler were mixed with rubber on a laboratory two-roll mill to create a base rubber compound (BRC). In the second stage, the BRC was mixed with the swelling filler in a closed laboratory plasti-corder rubber mixer, the Brabender Plasti-Corder® Lab-Station. Vulcanization was carried out at 160 °C. For the obtained samples, the physical-mechanical and sorption properties were determined. It has been shown that the carboxylated powdered lignocellulose from oat straw increases the strength properties of rubber in comparison with Na-CMC. It has been shown that when the carboxylated powdered lignocellulose from oat straw is introduced into the rubber composition, the degree of rubber swelling in aqueous solutions of various mineralizations increases by 50 and 100% in comparison with a noncarboxylated lignocellulose. [ABSTRACT FROM AUTHOR]

The solubility of the components in the ZnSO4 - KNO3 - H2O system was studied by the visual-polythermal method in the temperature range from -7.0°C to 42.0°C. The phase diagram delimits the fields of ice crystallization, KNO3, K2SO4·ZnSO4·6H2O, and ZnSO4. A solubility diagram was constructed, and a new compound K2SO4·ZnSO4·6H2O was separated. The new compound was identified by chemical, X-ray phase, thermogravimetric, and IR spectroscopic analysis. [ABSTRACT FROM AUTHOR]

The title compound, [Co(NCS)2(C6H7NO)]n or Co(NCS)2(2-methylpyridine Noxide), was prepared by the reaction of Co(NCS)2 and 2-methylpyridine Noxide in methanol. All crystals obtained by this procedure show reticular pseudo-merohedric twinning, but after recrystallization, one crystal was found that had a minor component with only a very few overlapping reflections. The asymmetric unit consists of one CoII cation, two thiocyanate anions and one 2-methylpyridine N-oxide coligand in general positions. The CoII cations are octahedrally coordinated by two O-bonding 2-methylpyridine N-oxide ligands, as well as two S- and two N-bonding thiocyanate anions, and are connected via μ-1,3(N,S)-bridging thiocyanate anions into chains that are linked by μ-1,1(O, O) bridging coligands into layers. No pronounced directional intermolecular interactions are observed between the layers. The 2-methylpyridine coligand is disordered over two orientations and was refined using a split model with restraints. Powder X-ray diffraction (PXRD) indicates that a pure sample was obtained and IR spectroscopy confirms that bridging thiocyanate anions are present. Thermogravimetry and differential thermoanalysis (TG-DTA) shows one poorly resolved mass loss in the TG curve that is accompanied by an exothermic and an endothermic signal in the DTA curve, which indicate the decomposition of the 2-methylpyridine N-oxide coligands. [ABSTRACT FROM AUTHOR]

Background. The study of the degree of functionality of carboxyl groups, the influence of mass ratios of reagents on the yield and properties of products is relevant. Purpose. To determine options for the formation of functional groups on the surface of MGU when modified with zirconium stearate. Methodology. It has been shown that the formation of functional groups is possible at the level of functionality of mesoporous carbon with a mass ratio (C17H35COOH+ZrO2): MGU of more than 0.4:1 and carboxyl groups of at least 0.6 mmol/g. Originality. The composition of the reagents was selected in which zirconium atoms are coordinated with the surface of the MSU, and MSU are coordinated with the stearate-zirconate groups, having good compatibility with non-polar solvents. Findings. It was established that the zirconium (IV) atom, as part of the functional groups, is associated with two stearate ions and two carboxyl groups on the surface of the MGU. [ABSTRACT FROM AUTHOR]

New conception of spin‐tautomery was developed based on the results of quantum chemical investigation of the endohedral Y@C60 complex. The embedding energies of yttrium into the fullerene cavity, dipole moments, polarizabilities, and IR spectra in the doublet and quartet spin states were calculated by the density‐functional theory quantum chemical methods. The degeneracy degree of the state of the complex is retained upon doublet–quartet excitation, since a twofold increase in the number of electron spin projections is compensated by a twofold decrease in the number of equivalent potential energy minima. The non‐conservation of spin by an endohedral complex with a heavy atom makes it possible to interpret the interconversion of doublet and quartet states as a non‐degenerate spin‐tautomery. [ABSTRACT FROM AUTHOR]

The object of the study is ultrafine bismuth barium borate glasses 20Bi2O3–хBaO–(80−х)B2O3, х = 5, 10, or 20 mol % BaO, synthesized using a unique version of the sol–gel method and holding promise for fabricating functional crystalline glass ceramics, in particular, based on yttrium aluminum garnet. A DSC analysis of the obtained charge material with 0.5 µm spherical particles revealed their glassy state at temperatures of 450–475°C. The presence of glass in particles of such a small size allows the use of the so-called cluster approximation in a quantum-chemical study of the geometric and electronic structure of glasses by the DFT/UB3LYP/LanL2DZ method. Calculated IR absorption spectra are compared with the experimental spectra of the obtained dispersed samples. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HAP) is the main mineral component of bones and teeth. It is widely used in medicine as a bone filler and coating for implants to promote new bone growth. Ion substitutions into the HAP structure highly affect its properties. One of the most important substituents is magnesium. This paper presents new results obtained using high-precision hybrid density functional theory calculations for Mg/Ca substitutions in HAP in a wide magnesium concentration range within a 2 × 2 × 2 supercell model. Experimental data on the mechanochemical synthesis of HAP-Mg samples with different Mg concentrations are also presented. A comparison between the experiment and the theory showed good agreement: the HAP-Mg unit cell parameters and volume decreased with increasing degree of Mg/Ca substitution. The changes in the distances between the Ca and O, Ca and H, and Mg and O ions upon Mg/Ca substitution in different calcium positions was analyzed. The resulting asymmetry and distortion of the cell parameters were evaluated. It was shown that bulk modulus, energy levels, and band gap depend on the degree of Mg substitutions in the Ca1 and Ca2 positions. The formation energies of Mg/Ca substitutions showed non-monotonic behavior that was different for Ca1 and Ca2 positions. The Ca2 position had a slightly higher probability (~5 meV/f.u.) of substitution than Ca1 position at a Mg concentration x = 0.5. At x = 1, substitution in both positions can coexist. The simulated IR spectra for different Mg/Ca substitutions showed that Mg in the Ca2 position changes the IR spectrum more significantly than Mg in the Ca1 position. Similar changes were recorded in the IR spectra of the synthesized samples. The electronic structure is shown to be sensitive to the number and position of substitutions, which may be used to tweak the optical properties of the HAP-Mg material. [ABSTRACT FROM AUTHOR]

The effect of irradiation of AI-92 grade gasoline with benzene additive was studied. The kinetics of the processes was examined at temperature T = 20°C, dose rate P = 0.072 Gy/s in the absorbed dose range (D) of 27–78 kGy. The results of gas chromatography-mass spectrometry (GC/MS) analysis, IR spectroscopic studies, and determination of the density and viscosity of samples before and after irradiation at various absorbed doses are reported. An assessment of the physicochemical parameters of γ-irradiated gasoline with 1, 2, 4, 6% benzene additives shows that γ-radiation negatively affects the operating parameters (viscosity and density) of AI-92 gasoline. The optimal concentration of benzene in gasoline is 6%, at which viscosity and density diminish with increasing absorbed dose. The kinetics of post-polymerization processes within 8 months after the end of irradiation shows that the rate of the process and its proportion in the total polymerization depend on the irradiation time, the density of the initial mixture and the dose. [ABSTRACT FROM AUTHOR]

Background and Objectives: Succinic acid is widely used in medicine, in particular, in the treatment of cardiological, neurological and endocrinological diseases. An urgent task of pharmacology is to increase the degree of bioavailability and solubility of drugs. One of ways to increase the therapeutic effect of drugs is the development of their polymorphic modifications, which contribute to a more pronounced therapeutic effect. One of ways to obtain new forms of succinic acid with better solubility and bioavailability is polymorphic modification nanotechnology based on the recrystallization of organic substances. We analyze the conformers and the influence of the aqueous environment on the physical-chemical properties of succinic acid. Materials and Methods: Spectral manifestations of modified succinic acid polymorphism and aqueous environment influence on spectral and energy characteristics are investigated on the integrated approach (experiment, theory) basis. The IR spectra of succinic acid are measured in the region of 600–4000 cm−1. The structures of an isolated molecule and a fragment of a chain associate of succinic acid conformers and their complexes with water are calculated using the density functional theory (DFT). The IR spectra and structures of complexes are calculated and compared with experimental data. The effect of hydrogen bonding on physical-chemical properties of succinic acid under recrystallization conditions is evaluated. Results: As a result of research, various succinic acid structures have been considered, as a result of which, by analyzing the energy difference, variants of conformers have been found both for one molecule and for the succinic acid dimer of the chain associate fragment. When water molecules are added, the characteristic peaks of the high-frequency region of the spectrum are shifted, that indicates the formation of hydrogen bonds. Conclusions: As a result of studies of the recrystallizated succinic acid physical-chemical properties a change in the crystal morphology has been detected based on the results of scanning electron microscopy. Water molecules, which remain in the structure of the modified molecular complex, have a great influence on the spectral characteristics of succinic acid. This has been discovered by comparing experimentally measured and calculated IR spectra of modified succinic acid. When water molecules are added to the conformers of an isolated molecule and a fragment of a chain associate of succinic acid, a shift of the characteristic peaks of the high-frequency spectral region corresponding to the valence vibrations of the O-H bond of the hydroxyl group of succinic acid is observed, that indicates the formation of hydrogen bonds. Analysis of interaction of succinic acid with water molecules indicates that during the preparation of polymorphic modifications, after the freeze-drying stage, water molecules are present in the modified succinic acid. In turn, the presence of the interaction of succinic acid with water molecules promotes stronger hydrogen bonding, that leads to a change in the physical-chemical properties of succinic acid.

The article presents the results of the experimental study on the starch nitration process with aqueous solutions of nitric acid. This nitrating medium has a number of advantages over the nitric and sulfuric acids mixture commonly used in industry, in particular it concerns the chemical stability of resulting starch nitrate. The aim of this work is to establish the dependence of nitration degree of starch on the nitration process parameters, taking into account changes in the chemical composition of its macromolecules. The experimental research method involved the use of ferrous sulfate method to determine the nitration degree of starch and IR-Fourier spectroscopy to analyze the macromolecules chemical composition. The parameters of the nitration process were changed in the following ranges: the mass fraction of water in acid solution of 0 to 35%, the temperature of 3.4 to 800 Ñ, the nitration module, as the ratio of the mass of the acid solution to the mass of potato starch of 1 to 40, and the nitration time of 1 to 180 min or 24 h. Based on the experimental results, it was found that the maximum degree of starch nitration is achieved with a water mass fraction in the nitrating solution of about 2%; a further increase in its content leads to a decrease in the starch nitration degree. The increase in the starch nitration degree to the maximum value in this case indicates the nucleophilic mechanism of starch nitration. It is shown that the temperature has a weak effect on the starch nitration degree, and nitrates of oxidized starch are formed under the conditions of high temperature. Increasing the nitration modulus leads to an increase in the starch nitration degree. The effect of nitration time on the starch nitration degree is related to the starch property to dissolve in nitric acid. The initial stage of starch nitration process proceeds at a high rate, which is a consequence of the acid intense penetration into the starch amorphous regions and their dissolution. In the following stages, the nitration process is slowed down due to the acid diffusion into the starch crystalline regions. If nitration is continued, a practically stable value of the nitration degree is achieved in the resulting starch nitrate. The obtained results allow choosing rational conditions for preparation of starch nitrate, which is a powerful explosive. [ABSTRACT FROM AUTHOR]

Herein, the Hirshfeld surfaces analysis of the crystalline methylone hydrochloride was performed in order to analyze NH⋯Cl, CH⋯Cl, and CH⋯O intermolecular interactions and study the formation of the NН2+–Cl− salt fragment in methylone hydrochloride crystal. There are two isomeric dimers with parallel and side-by-side orientation extracted from the crystal packing to model the IR spectrum of the crystalline methylone hydrochloride within the framework of density functional theory (DFT) and B3LYP/6-31G(d,p) method. We have assigned and interpreted all observed IR bands in the experimental spectrum of the 3,4-methylenedioxymethcathinone hydrochloride standard crystal sample that is important for forensic-medical examination. It was shown that intermolecular interactions between the NН2+ and Cl− ionic moieties occur in crystalline samples that confirm the presence of the ionized form of the methylone hydrochloride compound with the NН2+Cl− fragment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Shortwave infrared micro spectroscopy (SWIR) enables the measurement of water rotational relaxation time. • Water relaxation time measured by SWIR agrees with that measured by dielectric spectroscopy up to 100psec within 20% accuracy. • SWIR allows the sub-zero measurement of water relaxation time in solutions where ice and solution form a slurry. The shortwave infrared spectroscopy (SWIR) is the noble method which allows to evaluate the rotational relaxation time of water (RRTW) in a sample. Because SWIR requires the reference sample of pure water, the measurement temperature is limited only at above 0 °C. In this study, we expanded this temperature limitation of SWIR by using alternative reference solutions with freezing points below 0 °C, including sugar and glycerol solutions. The results showed that some reference sample solutions are useable for evaluating RRTW in samples below 0 °C. It was found that RRTW in solution measured by newly proposed SWIR agrees with RRTW measured by dielectric spectroscopy in 10% accuracy when it is shorter than 100psec. [ABSTRACT FROM AUTHOR]

We studied the sorption of silver, gold, and copper ions into powdered hydrolyzed fibroin derived from silk fibroin fibers. Metal ions sorbed into hydrolyzed fibroin have been found to interact with active functional groups over time. It was hypothesized that the silver and gold ions sorbed into hydrolyzed fibroin would form nanoparticles as a result of the reduction reaction, while the copper ions would form a coordination bond. Charmm22 force field calculations were performed on this basis. The IR spectral results obtained by calculations were compared with the IR spectral results obtained in practice, and it was proved that silver and gold nanoparticles were formed and that copper ions formed coordination bonds with fibroin

A vibrational analysis of various poly(o-aminophenol) structures has been undertaken using first principles methods. It is shown that a mixture of quinoid and keto forms of poly(o-aminophenol) gives rise to a simulated spectrum that replicates the experimental infrared spectra of plasma-produced poly(o-aminophenol) better than either the quinoid or keto poly(o-aminophenol) spectra alone. An unassigned peak in the spectrum is attributed to hydrogen bonding to the silica substrate.

Immunoglobulin and tumor necrosis factor complex formation, which is the basis of immunosuppressive drug etanercept therapeutic action, has been studied using quantum chemical modeling and molecular dynamics. The effect on the possibility of cyanine 7 on hydrogen bonds formation between amino acids from tumor necrosis factor and immunoglobulin has been considered. Analysis of dye effect on tumor necrosis factor and immunoglobulin complexation is caused by need for its use as a fluorescent label of etanercept when studying this drug passing through vessels and tissues of body in vivo. Computer simulation was based on molecular structures and IR spectra calculation using the density functional theory methods, followed by an analysis of formed hydrogen bonds parameters, as well as on the study of tumor necrosis factor protein structure dynamics. It has been found that cyanine 7 has a weak effect on amino acids complexation and, therefore, does not lead to therapeutic effect decrease, which makes it possible to use cyanine 7 for labeling etanercept.

Staggered decamethyl-ferrocene (*Fc) becomes the lower energy conformer at low temperature, whereas the eclipsed conformer of ferrocene (Fc) is more stable. The powerful infrared (IR) spectroscopy which has remarkably provided signatures of ferrocene (Fc) in eclipsed and staggered conformers recently is employed to investigate methylation of Fc. The most significant consequences of the full methylation of Fc in the IR spectra are the blue shift of the band at ~ 800 cm−1 in Fc to ~ 1500 cm−1 in *Fc, and the enhancement of the C–H stretch band at ~ 3200 cm−1 region in *Fc. Further analysis reveals large impact of Fc methylation on core electron energies of the centre Fe atom (1s22s22p63s23p6). The Fe core electron energy changes can be as large as ~ 10 kcal mol−1 and are directional—the Fe 2pz and 3pz orbitals along the *Cp–Fe–*Cp axis (Cp centroids, vertical) change more strongly than other Fe core electrons in px and py orbitals. The directional inner shell energy changes are evidenced by larger inner shell reorganization energy. Energy decomposition analysis (EDA) indicates that methyl groups in *Fc apparently change the physical energy components with respect to Fc. The large steric energy of *Fc evidences that the closest hydrogens on adjacent methyl groups of the same *Cp ring in crystal structure are 0.2–0.4 Å closer than the hydrogens on nearest-neighbour methyl groups on opposing rings in *Fc. A significant increase in Pauli repulsive energy contributes to the large repulsive steric energy in *Fc. [ABSTRACT FROM AUTHOR]

The atmospheric chemistry of CCl2FCH2CF3 (HFCF‐234fb) was examined using FT‐IR/relative‐rate methods. Hydroxyl radical and chlorine atom rate coefficients of k(CCl2FCH2CF3+OH)= (2.9 ± 0.8) × 10−15 cm3 molecule–1 s–1 and k(CCl2FCH2CF3+Cl)= (2.3 ± 0.6) × 10−17 cm3 molecule–1 s–1 were determined at 297 ± 2 K. The OH rate coefficient determined here is two times higher than the previous literature value. The atmospheric lifetime for CCl2FCH2CF3 with respect to reaction with OH radicals is approximately 21 years using the OH rate coefficient determined in this work, estimated Arrhenius parameters and scaling it to the atmospheric lifetime of CH3CCl3. The chlorine atom initiated oxidation of CCl2FCH2CF3 gives C(O)F2 and C(O)ClF as stable secondary products. The halogenated carbon balance is close to 80% in our system. The integrated IR absorption cross‐section for CCl2FCH2CF3 is 1.87 × 10−16 cm molecule−1 (600–1600 cm−1) and the radiative efficiency was calculated to 0.26 W m−2 ppb1. A 100‐year Global Warming Potential (GWP) of 1460 was determined, accounting for an estimated stratospheric lifetime of 58 years and using a lifetime‐corrected radiative efficiency estimation. [ABSTRACT FROM AUTHOR]

Complex composite materials are used in many areas of dentistry. Initially, chemically hardened materials were also used, and in this group nanohybrid composites are highly valued. They are often used today, mainly for the direct reconstruction of damaged hard tooth tissue materials for rebuilding damaged tissues using indirect adhesive techniques. The research was conducted to determine the mechanical properties of materials with nanofillers. The article focuses on methods of important test methods for dental prosthetics: resilience, abrasion, wear test, impact strength, hardness, SEM, and chemical analysis. As part of this work, five different series of hybrid composites with nano-fillers were tested. The mechanical properties of composites, such as compressive strength, microhardness, flexural strength, and modulus of elasticity, depend mainly on the type, particle size, and amount of filler introduced. The obtained test results showed that the type and amount of nanofiller have a significant influence on the mechanical and tribological properties. The introduction of nanofillers allowed us to obtain higher mechanical properties compared to classic materials discussed by other researchers. The study observed a change in vibrations in the IR spectrum, which allowed a comparison of the organic structures of the studied preparations. [ABSTRACT FROM AUTHOR]

The reaction of methyl mercaptan (CH3SH) with groups such as •OH, O•, and SO2 in the air forms acid rain and photochemical smog, which damage the atmosphere seriously. It is found that methyl mercaptan can be degraded effectively by studying its dissociation characteristics of it in an external electric field. The total energy, C–S bond length, HOMO–LUMO energy gap, electric dipole moment, as well as charge distribution, IR spectrum, and dissociation potential energy surface of methyl mercaptan molecule under external electric field (0–12.5 V nm–1) were studied by density functional theory (DFT) at B3LYP/6-311++(d,p) basis set level. Moreover, the UV–Vis absorption spectrum of methyl mercaptan with the external electric field was obtained by CIS/6-311++(d,p) method. The calculation results show that along the direction of the C‒S bond line, the molecular system energy gradually decreases, while the C–S bond length increases gradually. Meanwhile, the dipole moment monotonously decreases with the field, and the HOMO–LUMO energy gap EG monotonically decreases after a slight increase at the beginning with the increase of the field. When the applied external electric field is gradually enhanced, the barrier of the C–S bond of methyl mercaptan molecule is reduced. It shows that when the employed external electric field strength arrives at 21.91 V nm–1, the C–S bond can be broken completely, that is, methyl mercaptan is degraded. [ABSTRACT FROM AUTHOR]

Natisite, a natural tetragonal (P4/nmm) modification of Na2TiSiO5 = Na2TiO(SiO4) is an abundant indicator mineral of relatively low-temperature (no higher than 300–350°C) peralkaline (hyperagpaitic) hydrothermal assemblages in the Lovozero and Khibiny alkaline plutons, Kola Peninsula, Russia. The proportion of natisite in hypersodic (with Na K) hydrothermal veins in Lovozero and in the hydrothermally altered zones of potassium-rich pegmatites in Khibiny is up to 30 and 10 vol %, respectively; i.e., natisite can be a rock-forming mineral and the major Ti concentrator in the rock. In Lovozero, natisite is a primary mineral crystallized from hydrothermal solution, whereas in Khibiny, natisite is secondary: it predominantly occurs as pseudomorphs after earlier Ti minerals, namely, ilmenite, titanite, aenigmatite, lamprophyllite and rinkite. The chemical composition of natisite is rather stable, close to Na2TiSiO5. A very bright blue to bluish white fluorescence in shortwave ultraviolet light (λ = 245 nm) is an important identification feature of natisite. The crystal structure of natisite was first solved for a natural sample (Mt. Rasvumchorr, Khibiny), R1 = 1.97%. A comparative study of natisite and other titanosilicates with tetragonal pyramids TiO5 revealed a distinct negative correlation between the length of an essentially covalent Ti–O bond in the titanyl group and the frequency of its stretching vibrations in the IR spectrum. [ABSTRACT FROM AUTHOR]

Fluoborite extremely close to the fluorine endmember of the fluoborite Mg3[BO3]F3–hydroxylborite Mg3[BO3](ОН)3 series has been found in exhalations of the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. The proportion of the molecule Mg3[BO3](ОН)3 in it does not exceed 1 mol %. This borate is associated with halite, sylvite, langbeinite- and aphthitalite-group sulfates, anhydrite, krasheninnikovite, sanidine, fluorophlogopite, hematite, tenorite, chubarovite, alluaudite-group arsenates, lammerite, and urusovite. Fluoborite occurs as tiny acicular or hairlike crystals up to 5 mm long assembled in radial, near-parallel or chaotic open-work aggregates up to 10 cm across. Its chemical composition determined by electron microprobe is, wt %: 38.71 Mg, 5.90 B, 25.52 O, 30.83 F, total 100.96; the empirical formula is Mg2.97B1.02O2.98F3.03. The unit-cell parameters calculated from the powder X-ray diffraction pattern are: a = 8.808(4), c = 3.098(2) Å, V = 208.1(3)Å3. The IR and Raman spectra of borates of the fluoborite–hydroxylborite series are given and discussed. Fluoborite occurring in the Arsenatnaya fumarole crystallized at a temperature no lower than 450°C. The fumarolic genetic type is novel for this borate. [ABSTRACT FROM AUTHOR]

X-ray crystallography has been used to characterise the title compound for the first time, 1H NMR, 13C NMR and IR spectroscopic data has also been updated from earlier reports. [ABSTRACT FROM AUTHOR]

By DFT method with B3LYP, PBE, CAM-B3LYP, and B97D functionals, it was found that the molecule 4-(4-tritylphenoxy)phthalonitrile (TPPN) has four conformers. The geometric structure, vibrational frequencies, electronic characteristics, and thermodynamic functions of conformers, as well as the structure and energy of transition states, were determined. IR spectrum of TPPN film contains vibrational bands belonging to different conformers. The assignment of bands was performed basing the distribution of normal vibration energy on internal coordinates. A synchronous electron diffraction/mass spectrometric experiment was performed to determine the structure of conformers in a saturated TPPN vapor. The elemental composition of the ions recorded in the mass spectrum indicates the thermal stability of TPPN at least up to T = 200 °C. The difference in the structure of tetrasubstituted metal phthalocyanines, which can be synthesized from different TPPN conformers, has been shown. [ABSTRACT FROM AUTHOR]

The IR spectral features of coal determined for individual wavenumber intervals may be used in calibration of the properties of coal concentrates: the yield of volatiles, plastic-layer thickness, vitrinite reflection coefficient, and total content of fusinized components. Multidimensional data are analyzed. The precision of the calibration models permits rapid analysis of coal quality. [ABSTRACT FROM AUTHOR]

A new aroylhydrazone ligand, di-2-pyridyl ketone-4-methoxybenzhydrazone (DKMBH·H2O) and its three complexes with cobalt(II), copper(II) and zinc(II), labelled Co(DKMB)Cl (1), Cu(DKMB)Cl (2), and Zn(DKMB)Cl (3) have been prepared and structurally studied. The spectroscopic techniques like IR, UV-Vis, MS, and ¹H NMR, as well as CHN analysis and thermal analysis, have been used to physico-chemically characterize the synthesized compounds. The IR and ¹H NMR analyses have made clear that the aroylhydrazone remains in the amido form in the solid state. The IR spectral measurements further support the tridentate character of the NNO donor aroylhydrazone. In all complexes, pyridine nitrogen, azomethine nitrogen, and iminolate oxygen of the tridentate aroylhydrazone are involved to coordinate to the metal centre. [ABSTRACT FROM AUTHOR]

The solubility of components in the system calcium chlorate - sodium salt of monochloroacetic acid - water is studied by a visual and polythermal method in a wide interval of temperatures and concentration. On the phase diagram the fields of crystallization of ice, Ca(ClO3)2×6H2O, Ca(ClO3)2×4H2O, Ca(ClO3)2×2H2O, ClCH2COONa and a new phase are differentiated. Formation of new compounds is confirmed by IR spectrum, chemical and X-ray phase analytical methods. The relation between the structure and property of a system [40 % Ca(ClO3)2 + 60 % H2O] - ClCH2COONa is studied and its diagram is constructed. [ABSTRACT FROM AUTHOR]

X-ray crystallography was used to characterise the title compound for the first time, and the 1H NMR, 13C NMR and IR spectroscopic data from earlier reports were also updated. [ABSTRACT FROM AUTHOR]

Thaumasite was found in zoned calcic skarns hosted by the monzonitic rocks of the Zvezdel pluton, Eastern Rhodopes. Associated minerals are wollastonite, clinopyroxene, grossular-andradite garnets, Ti-rich garnets, plagioclase, calcite, quartz, epidote, prehnite, and chlorite. Titanite, apatite and magnetite are present as accessories. The mineral has been characterized using optical microscopy, PXRD, SEM/EDS, EPMA, and FTIR. Thaumasite forms sheaf-like and fan-shaped aggregates, which consist of acicular crystals elongated along the c axis. The IR spectrum of thaumasite is in accordance with the chemical composition and contains absorption bands in the range 3500-3291 cm-1 (O-H stretching vibrations); 1683, 1650 cm-1 (bending vibrations of H2O); 1389 cm-1 (stretching vibrations of CO32-);1100, 1069 cm-1 (asymmetric stretching vibrations of SO42-); 882 cm-1 (symmetric bending vibration of CO32-); 768,742, 680 cm-1 (Si-O stretching vibrations of Si(OH)6 octahedra); 670 cm-1 (bending vibrations of SO42-). [ABSTRACT FROM AUTHOR]

Background and Objectives: Polyelectrolyte capsules are one of the most promising materials for targeted drug delivery – one of the rapidly developing areas of modern chemistry, pharmacology and medicine. They have a wide range of applications due to various methods of controlling their physical and chemical properties. In this paper, the possibility of drug delivery and retention in cells due to the formation of hydrogen bonds between a polyelectron capsule and highly toxic drugs on the example of mitoxantrone is investigated by molecular modeling. Materials and Methods: Using molecular modeling by the B3LYP density functional theory method with a base set of 6–31 G (d), we analyze the formation of hydrogen bonds and their effect on the IR spectra and structure of the molecular complex formed as a result of the interaction of the drug mitoxantrone and polyelectrolyte capsules consisting of polyarginine and dextran sulfate. Due to the large size of the polyarginine molecule, which consists of repeating fragments, one link is used in the work, namely arginine. Results: As a result of calculations, various variants of molecular complexes consisting of mitoxantrone, polyarginine and dextran sulfate were considered. The results have shown that dextran sulfate forms weak hydrogen bonds with polyarginine and with mitoxantrone. Polyarginin forms strong and close to strong bonds with mitoxantrone. Conclusions: Based on the results obtained, it can be concluded that polyarginine plays a significant role as a substance that holds mitoxantrone in the capsule, and dextran sulfate, on the contrary, plays the role of a buffer substance. Encapsulation can be considered as one of the main mechanisms of targeted drug delivery and their retention in the cells and, thus, increasing the therapeutic effectiveness of drugs.