The work is devoted to the study of preferential solvation of dimethyl sulfoxide in binary solvents by IR spectroscopy. The absorption frequencies of stretching vibrations of S=O group of dimethyl sulfoxide in mixtures of carbon tetrachloride with acetone, acetonitrile and nitromethane at different ratios of components were determined. Shifts of absorption frequencies of stretching vibrations of the S=O group of dimethyl sulfoxide (Δνpref. solv) in binary solvents as a measure of preferential solvation were calculated. Solvation shells (x*) in binary solvents for the S=O group of dimethyl sulfoxide have been determined using absorption frequencies. The role of the second component of the binary mixture on the effects of preferential solvation and changes in solvation shell composition (x*) was discussed.

Inclusion compounds of diclofenac sodium, a non-steroidal anti-inflammatory drug, with native α-, β- and γ-cyclodextrins at varying levels of hydration were prepared by co-grinding in a ball mill. Using TG/DSC analysis, powder X-ray diffraction and solid-state IR spectroscopy, it was shown that when equimolar mixtures of native cyclodextrin and diclofenac are milled, complete inclusion of this pharmaceutical ingredient occurs, regardless of cyclodextrin hydration. The absence of water-guest competition in the solid-state inclusion process is explained by high affinity of diclofenac sodium to cyclodextrins. The prepared complexes have a significantly lower thermal stability than the separate native cyclodextrins and diclofenac sodium.

Heating of powders of linear dipeptides can give their cyclic analogs with practically useful properties. No solvents are used, and the product yield can be close to 100

Благодаря уникальным электронным и оптическим свойствам малослойный черный фосфор (МЧФ) является перспективным двумерным материалом для применения в различных областях химии и физики. Химическая функционализация поверхности МЧФ является эффективной стратегией для улучшения стабильности к окислению, а также для настройки и придания новых свойств фосфорному материалу. В данной работе предложен подход к иммобилизации комплекса [NiBr2(phen)] (где phen – 1,10-фенантролин) на поверхности МЧФ путем ковалентной функционализации МЧФ 1,10-фенантролином и последующим образованием комплекса с NiBr2. Полученные фосфорсодержащие материалы на основе МЧФ, функционализированного комплексом [NiBr2(phen)] охарактеризованы комплексом физико-химических методов, включая просвечивающую электронную микроскопию (ПЭМ), атомно-силовую микроскопию (АСМ), а также твердотельную ЯМР-, ЭДС-, КР- и ИК-спектроскопию.

A 2D material few-layer black phosphorus (FLBP) has promising applications in various fields of chemistry and physics due to its unique electronic and optical properties. Chemical functionalization of the FLBP surface is an effective strategy for improving the oxidative stability of the material, tuning its intrinsic properties or endowing it with new properties. The present work proposes an approach to the immobilization of the [NiBr2(phen)] complex (phen = 1, 10-phenanthroline) on the FLBP surface via covalent functionalization of FLBP with 1,10-phenanthroline and subsequent complexation with NiBr2. The obtained FLBP-based materials functionalized by the [NiBr2(phen)] complex were characterized by a set of physicochemical methods such as transmission electron microscopy, atomic force microscopy, solid-state NMR, energy-dispersive spectroscopy, Raman spectroscopy, and IR spectroscopy.

Inhalation delivery systems, which find use in aerosol therapy, are currently attracting increased attention. A drug administered for inhalation therapy through the respiratory tract has increased bioavailability. Special attention should be paid to the size and shape of the microparticles, which should be in the range 1 – 3 μm and spherical. Microspheres of composites of dipyridamole with bovine serum albumin and lysozyme were produced using a spray-drying procedure in the present work.

Thermal treatment of linear dipeptides in solid state makes it possible to obtain their cyclic analogues in high yield and without additional expenses. At the same time, such reactions occurring under the conditions of crystal lattice restrictions with the participation of molecules in the zwitterionic form have not been sufficiently studied. In this work, the cyclization reaction of the L-leucyl-L-valine dipeptide in the crystalline phase upon heating was studied. Using isoconversion kinetics approaches, a kinetic model describing this process was found, and kinetic parameters were calculated, including activation energy, Arrhenius factor, and reaction order. The enantiomeric purity of the resulting cyclic product was assessed. The self-assembly of linear and cyclic dipeptides on a solid substrate was studied. The results of the study will be useful in determining mechanisms of the cyclization reactions of dipeptides in the solid state, and can also be used in the development of effective and cost-efficient methods for the production of cyclic dipeptides.

В работе изучено влияние размера макроцикла нативных циклодекстринов и их гидратации на инкапсуляцию ритонавира в условиях механического перемалывания. Разработан способ оценки степени включения ритонавира циклодекстринами, используя кристаллизацию несвязанного «гостя» в продуктах перемалывания при обработке парами воды. Установлено, что ритонавир практически полностью связывается безводными α-, β- и γ-циклодекстринами с образованием соединений включения. Для гидратов циклодекстринов соотношение структура-свойство для связывания ритонавира в зависимости от размера макроцикла «хозяина» является нелинейным. Ритонавир полностью связывается насыщенным гидратом β-циклодекстрина и промежуточными гидратом γ-циклодекстрина. Степень включения ритонавира насыщенными гидратами α-циклодекстрина и особенно γ-циклодекстрина невелика, что обусловлено конкуренцией этого гостя с водой.

We study how the size of the macrocycle of native cyclodextrins and their hydration influence the inclusion of ritonavir under mechanical grinding conditions. A procedure is proposed to estimate the degree of inclusion of ritonavir by cyclodextrins using the crystallization of the unincluded guest in the grinding products at the water vapor treatment. Ritonavir is almost completely included by anhydrous α-, β-, and γ-cyclodextrins, resulting in the formation of inclusion compounds. The structure–property relationship between ritonavir inclusion in cyclodextrin hydrates and the size of the host macrocycle is nonlinear. Ritonavir is completely included by saturated β-cyclodextrin hydrate and intermediate γ-cyclodextrin hydrates. The degree of ritonavir inclusion by saturated hydrates of α-cyclodextrin and particularly of γ-cyclodextrin is small due to the competition of this guest with water.

Single crystal of Pr3+:LiGdF4 (C-Pr = 0.01 at.%) was grown in the resistive furnace by the Bridgman-Stockbarger method. The crystal was milled in an agate mortar. The obtained powder had a tetragonal structure (88 space group I4(1)/a). The specific heat of the sample gradually increases with the increase of temperature from 0.46 (at 200 K) to 0.62 J/g.K (at 389 K). These values are notably less in comparison to the phosphors based on LiYF4 and LiLuF4 counterparts. The luminescence spectra of Pr3+:LiGdF4 microparticles under 442 nm pulse laser excitation demonstrated temperature dependence of its shape in the 80-680 K temperature range. Specifically, the intensity of P-3(1) - H-3(j) emission increases in reference to P-3(0) - H-3(j) emission with the increase of temperature. This phenomenon was explained by the fact that P-3(1) and P-3(0) electron levels share their electron populations according to the Boltzmann law. The luminescence intensity ratio (LIR) was taken as a temperature-dependent parameter. The maximal absolute temperature sensitivity (S-a) was equal to 0.010 K-1 at 320 K. This value is bigger in comparison to other Pr3+ doped counterparts. The high temperature sensitivity in the 250-450 K temperature range allows using the Pr3+:LiGdF4 phosphors for biological and industrial applications. The relatively low specific heat minimizes the impact of the phosphors on the studied object for which the temperature reading is performed.

Inhalation delivery is a promising way of administration of antiplatelet drugs for the prevention of stroke. The bioavailability of drugs poorly soluble in water can be increased if microspheres based on protein molecules are used. Spray drying was used in the present work to obtain sodium caseinate microspheres with an average aerodynamic diameter of 2.8 μm containing a model hydrophobic antithrombotic drug (dipyridamole). The rate of dipyridamole dissolution and its concentration in aqueous solution could be increased if sodium caseinate was used. The obtained results made it possible to develop a strategy for creating systems based on a protein matrix for inhalation delivery of poorly soluble drugs.

Microspherical particles of composite drugs based on lysozyme and albumin, which can be used in inhalation administration, were prepared by spray drying. The composition of the complexes was determined using experimental and theoretical methods. The use of the protein matrix makes it possible to increase the dissolution rate of the drug in water. The obtained results can be useful for the development of new drug dosage forms with increased bioavailability.

The composition and stability constants of homo- and heteroligand copper(II) complexes with benzoic acid, p-methoxybenzoic acid, or o-hydroxybenzoic acid hydrazide and L-histidine have been determined by spectrophotometry and mathematical modeling methods in aqueous solution with 0.1 M KNO3 as background at 25.0°C. Structural features of some complexes formed in binary and ternary systems have been determined using IR spectroscopy and quantum-chemical calculations.

High-resolution nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy experiments were applied to obtain detailed information on the hydrocarbon chemistry of three light and three heavy crude oils. Quantitative fractions of aromatic molecules and functional groups constituting oil hydrocarbons were determined by 13C NMR spectroscopy and comparative analysis of the oil samples with different viscosity, origin and preliminary treatment. SARA composition and some important information about aromaticity, oxidation behavior, branching, aliphaticity and sulfurization of studied oil samples were obtained. Integral characteristics of high-resolution NMR and FTIR spectra have a great potential to study the structure and characterization of light and heavy crude oils, which could substitute present traditional fractionation procedures. Relationships between spectroscopic parameters obtained by high-resolution NMR and FTIR spectroscopy methods and crude oil compositions can be useful for fast prediction of crude oil properties due to different type of treatment, including thermal methods for enhanced oil recovery. Also quantitative proportions of functional groups obtained by NMR and spectral indices obtained by FTIR can be one of the criteria for developing fingerprint approach.

Inhalation administration is a promising alternative to the invasive drug delivery methods. The particle size required for ideal drug aerosol preparation is between 1 and 3 μm. The application of microspherical particles of solid dispersions enhances bioavailability of poorly soluble drugs due to the solubilization. In the present work, the spray drying process of the production of microspherical particles of solid dispersions of polyvinylpyrrolidone K29-32 with model hydrophobic drug, phenacetin, was optimized using the results of DSC, PXRD, and viscometry. The diameter of the obtained particles is within 1–3 μm range. The Gibbs energy of dissolution in water was shown to be negative for the mixture with polymer/phenacetin mass ratio 5 : 1. We have demonstrated that the optimal size distribution for the inhalation administration is obtained for microspherical particles produced using spray caps with 7.0 μm hole size. The dissolution rates of phenacetin from the produced microspherical particles were faster than that of drug powder. As evidenced by powder X-ray diffraction data, phenacetin stayed in amorphous state for 4 months in microspherical particles of solid dispersions. According to the obtained results, strategic application of the spray drying process could be beneficial for the improvement of the pharmaceutical properties of model drug, phenacetin.

A novel organic compound 9-(2,4-dinitrophenyloxy)-3,3,8-trimethyl-1,5-dihydro-[1,3]dioxepino[5,6-c]pyridine (DNPAP) has been synthesized and a nonlinear optical (NLO) crystal has been grown by slow evaporation method. Compound was subjected to different characterization analyses in order to find out its suitability for optoelectronic applications. Single crystal and powder X-ray diffraction analyses show that DNPAP crystallizes in the orthorhombic space group Pca21. The range of optical absorption was ascertained by recording UV–Vis spectrum. The second harmonic generation (SHG) test has shown that DNPAP possesses 6.4-times higher NLO efficiency compared to KDP.

The polarity and conformations of 2-aminophenyl-, 2-aminobenzyl-, and 2-nitrobenzyl(diphenyl)-phosphine oxides were studied by the dipole moment method, IR spectroscopy, and quantum chemical calculations. 2-Aminophenyl- and 2-aminobenzyl(diphenyl)phosphine oxides were found to exist preferentially as conformers with intramolecular hydrogen bond. 2-Nitrobenzyl(diphenyl)phosphine oxide is likely to be represented by equilibrium mixture of three conformers in which the phosphoryl and nitro groups are oriented syn or anti with respect to the \(PC_{sp^3 } C_{sp^2 } \) fragment.

The oxidation was performed of 2-(6,6-dimethylbicyclo[3.1.1]hept-2-ylmethylsulfanyl)ethanol II synthesized by adding 2-mercaptoethanol to (−)-β-pinene in the presence of a Lewis acid. The sulfoxide obtained is present in two polymorphic structures with different physical properties, spectral characteristics, and fungicidal activity.