Синтезированы новые оптически активные тиоэфиры и сульфоны на основе 2(5Н)-фуранона, 4-аминотиофенола и двух монотерпеновых спиртов – l-ментола и l-борнеола. Методом рентгеноструктурного анализа исследована кристаллическая структура двух оптически активных сульфонильных производных фуранонового ряда. В обоих кристаллах вещество представлено независимыми молекулами А и В, имеющими радикальные различия в конформациях и системе водородных связей. Показана продуктивность подхода детального рассмотрения всех стереохимических особенностей молекулы в кристалле по данным РСА с привлечением анализа поверхностей Хиршфельда.

In this study, a new method for producing a composite material composed of epoxy resin and 0.03wt.% modified graphene oxide (MLGO) was developed and tested, where the MLGO was concentrated near one surface of the composite using a magnetic field. This feature reduced the wear rate of that surface by 87% compared to pure epoxy resin and by 17% compared to the uniform distribution of MLGO in the epoxy matrix. Concentrating MLGO near the surface proved to be the most effective strategy for improving wear resistance, as it also prevented crack formation. Moreover, the MLGO nanofiller not only enhances mechanical properties and wear resistance but also imparts magnetic sensitivity and luminescence, making it a valuable component for advanced materials.

Получена новая кристаллическая Z' = 3 форма 15-ен-стевиола – 13-гидрокси-энт-каур-15-ен-19-овой кислоты. Методом рентгеноструктурного анализа обнаружен неизвестный ранее для соединений с каурановым скелетом ассоциат – гомохиральный циклический димер по типу «голова к голове, хвост к хвосту». Геометрия димера в кристалле и в газовой фазе по данными квантово-химических расчётов свидетельствует о напряжённости конструкции, проявляющейся в существенном отклонении от плоскости геометрии карбоксильного синтона. Проиллюстрировано отклонение неподеленных электронных пар карбонильных групп от связевых путей, показанное методом топологического анализа, дополненного анализом функции лапласиана электронной плотности.

We studied the morphological, structural, and optical studies of hydrophobic up-conversion NaYF4:Yb/Ho nanoparticles synthesized by the thermal decomposition method. To impart hydrophilic properties, the NaYF4:Yb/Ho nanoparticles were silanized using the following nonionic surfactants: Triton X-114, Tween 85, and PEG monooleate. As a result, a silicate shell formed on the surface of the nanoparticles, providing hydrophilic properties and stable colloidal solutions in water while maintaining their luminescent characteristics. The use of the most effective surfactant, Triton X-114, for silanization allowed for obtaining a narrow size distribution of NaYF4:Yb/Ho@SiO2 nanoparticles. The study of the temperature dependencies of luminescence spectra indicates the high potential of NaYF4:Yb/Ho and NaYF4:Yb/Ho@SiO2 nanoparticles for use as luminescent temperature probes.

The chemical structure of diborane was elucidated through the superposition of the vector fields of the electron density gradient ∇ρ(r), the electrostatic force Fes(r), and the kinetic force Fk(r), together with the analysis of the cumulative charges of the atoms and pseudoatoms delimited in the aforementioned fields. It was proposed that the Fk-pseudoatomic charge could be employed as a metric for quantifying the ionic component of a related atomic charge. The electron permeability across an internuclear turning surface─specifically, the zero-flux surface in Fk(r)─was characterized by probing it through mapping the total static potential φem(r). The conceptualization of post hoc electronegativity was presented for consideration. Our analysis revealed that the ordinary B-H and bent B-μ-H bonds in diborane demonstrate the polar covalent character with minor contributions of the ionic component. The former bond exhibits a greater electron permeability through the internuclear turning surface, indicating a stronger tendency for electron sharing between the corresponding nucleus-dominated regions. The electron density accumulation along the bent B-μ-H bond path diverges from the minimum action trajectories of the forces Fes(r) and Fk(r). This phenomenon can be associated with the structural strain within the angled, three-center two-electron bonding B-μ-H-B. The internuclear B···B paths were identified in Fes(r) and Fk(r), in contrast to ∇ρ(r). This fact, in conjunction with a pronounced electron permeability through the mutual turning surface between the two boron nuclei, implies a certain degree of electron exchange between the boron-dominated pseudoatomic regions. Furthermore, the anomalous [B-]H···μ-H intermolecular polar interactions were described between the strongly negatively charged hydrogen atoms in the monoclinic crystalline β-phase of diborane. In fact, the ionic contributions to the charges of the hydrogen atoms are shown to be relatively small.

In this work, polyurethane composites with petroleum asphaltenes and their modified derivatives have been obtained and studied. The changes in the mechanical and thermal characteristics of polyurethane composites depending on the content of asphaltene fillers in concentrations of 1 and 2.5 wt% are shown. The distribution of native and modified asphaltenes in the polymer matrix was assessed using the X-ray power diffraction method. Composites with native asphaltenes and asphaltenes bearing amino groups showed the best performance in terms of distribution homogeneity in the matrix of polyurethane obtained from 2,4-toluylene diisocyanate (TDI) and polyethylene glycol adipate. It has been shown that the use of carboxylated (CA) and sulfonated (SA) asphaltenes in polyurethane composites leads to incomplete curing of the polymer. A significant decrease in the strength and elongation at break, as well as an increase in material hardness, was recorded for a composite containing 2.5 wt% of sulfonated asphaltene. The use of aminated asphaltenes makes it possible to increase the elongation at break due to additional interaction with TDI at the production of polyurethane composites. Composites with native and sulfonated asphaltenes showed the best thermal stability.

Photocatalysts based on graphitic carbon nitride (g-C3N4) attracted considerable attention due to their efficiency in hydrogen production and decomposition of organic pollutants in aqueous solutions. In this work, a new approach to synthesis of g-C3N4-based heterostructures with improved photocatalytic properties was proposed. The properties of two different CdZnS/g-C3N4 and ZnIn2S4/g-C3N4 heterostructures synthesized and studied in the same conditions were compared. Pure g-C3N4 photocatalysts as well as CdZnS/g-C3N4 and ZnIn2S4/g-C3N4 heterostructures were synthesized using a one-pot method by calcining the mixture of the initial components. Photocatalytic properties of the synthesized substances were evaluated in a model reaction of rhodamine B decomposition induced by visible light. It was shown that ultrasonic treatment in the presence of a nonionic surfactant enhances the photocatalytic activity of g-C3N4 structures as a result of a higher photocatalyst dispersity. The electronic structures of the CdZnS/g-C3N4 and ZnIn2S4/g-C3N4 heterostructures were analyzed in detail. The photocatalytic activity of heterostructures was found to be 2–3-fold higher as compared with an unmodified g-C3N4 due to formation of a type II heterojunction and Z-scheme structures. Decomposition of rhodamine B occurred mostly via formation of active oxygen radicals by irradiation.

This paper presents a binding approach based on the electrostatic and kinetic force density fields and proposed to elucidate interatomic interactions, structures, and chemical reactions. Among other elements, it consists in the understanding of (i) the arrangement of pseudoatomic zero-flux surfaces (ZFSs), (ii) the mutual compression of force-field pseudoatoms of the same type, (iii) the penetration of a bonded atom into neighboring force field pseudoatoms, (iv) the distortion of the force fields, and (v) the occurrence of a binding path connecting two force-field attractors as the inherent consequences of the emergence and existence of any many-electron multinuclear system. Herein, the interatomic charge transfer and the reciprocal quantum-chemical response accompanying the covalent and noncovalent bond formation were studied using the abovementioned penetration, exemplified by Appel's salt. Such consideration gave rise to the concept of force-induced "push-pull" assembling of interacting (pseudo)atoms. In this regard, various halogen, chalcogen, and tetrel noncovalent interactions, as well as polar covalent bonds, were examined. Furthermore, the notion of the force-based binding structure was proposed instead of the bonding one, which defines the mutual connectivity of force-field pseudoatoms of the same type via binding paths. The thus-defined chemical structure proved to be more sensitive to variations in the configuration space of nuclear coordinates. It was found that the three-center chalcogen bonding Cl-center dot center dot center dot S-S and tetrel bonding Cl-center dot center dot center dot C center dot center dot center dot Cl- in the crystal studied resemble the initial and transition states of bimolecular nucleophilic substitution reactions, respectively. Their central atoms act as electron contributors with a different degree of the transferred electron density sharing. Being extracted from the crystal structure, the corresponding ion pairs undergo chemical rearrangement: Forming the covalent bonds Cl-S and Cl-C leads to the collapse of the pseudoatomic ZFSs and the alignment of the bond and binding paths in the internuclear regions.

The structure and magnetic properties of the single crystal of bis{1-[4-(4-pentyloxybenzoyl-oxy)phenyl]-1-amino-3-pentylprop-1-en-3-onate}copper(II), which shows nematic mesomorphism, were studied by X-ray diffraction and electron spin resonance spectroscopy.

The work presents core–shell nanoparticles (NPs) built from the novel Cu(I) complexes with cyclic P2N2-ligands (1,5-diaza-3,7-diphosphacyclooctanes) that can visualize their entry into cancer and normal cells using a luminescent signal and treat cells by self-enhancing generation of reactive oxygen species (ROS). Variation of P- and N-substituents in the series of P2N2-ligands allows structure optimization of the Cu(I) complexes for the formation of the luminescent NPs with high chemical stability. The non-covalent modification of the NPs with triblock copolymer F-127 provides their high colloidal stability, followed by efficient cell internalization of the NPs visualized by their blue (⁓450 nm) luminescence. The cytotoxic effects of the NPs toward the normal and some of cancer cells are significantly lower than those of the corresponding molecular complexes, which correlates with the chemical stability of the NPs in the solutions. The ability of the NPs to self-enhanced and H2O2-induced ROS generation is demonstrated in solutions and intracellular space by means of the standard electron spin resonance (ESR) and fluorescence techniques correspondingly. The anticancer specificity of the NPs toward HuTu 80 cancer cells and the apoptotic cell death pathway correlate with the intracellular level of ROS, which agrees well with the self-enhancing ROS generation of the NPs. The enhanced level of ROS revealed in HuTu 80 cells incubated with the NPs can be associated with the significant level of their mitochondrial localization.

A binding approach based on electronic force density fields was used to describe the structures of the molecule, dimer and crystal of a uracil derivative. Transferable multipole pseudo-atoms were successfully used to reconstruct the inner-crystal electronic force density fields.

The crystal structures of 3-chloro-5-hydroxy-1-(4-methylbenzyl)-4-[4-phenyl-1H-1,2,3-triazole-1-yl]-1,5-dihydro-2Н-pyrrol-2-one rac-1 and 1-benzyl-3-chloro-5-hydroxy-4-[4-phenyl-1H-1,2,3-triazole-1-yl]-1,5-dihydro-2Н-pyrrol-2-one rac-2 are studied. The reproducibility of a same-type homochiral chain in both chiral and racemic crystals is found. Molecular conformations, secondary interactions additionally cross-linking the chain, and π…π contacts between the cyclic molecular moieties are analyzed.

We confirm our previously formulated rule about the possibility of a spontaneous resolution of enantiomers of a series of 5-hydroxy-3-pyrrolin-2-one thioderivatives. Crystal packings of three racemic compounds are compared. A supramolecular associate of the same type (a hydrogen-bonded dimer) is found, which is differently packed in the 3D structure of the crystals.

A rare phase behavior of rac-1-benzyl-3-bromo-4-[(4-chlorophenyl)sulfanyl]-5-hydroxy-1,5-dihydro-2H-pyrrol-2-one, which consists of the formation of two normal monoclinic and hexagonal conglomerates and a monoclinic racemic compound, has been discovered by thermochemical and X-ray diffraction methods. Its monoclinic racemic compound is reproducibly formed as a result of the suspension by stirring the solid phase in hydrocarbons at room temperature, while routine crystallization from a solution leads to the formation of a mixture of the two conglomerates. Thermochemical data suggest that the monoclinic conglomerate is metastable within the entire temperature range, the monoclinic racemic crystal is stable under normal conditions (20 degrees C) up to 110 degrees C, and the hexagonal conglomerate is stable at elevated temperatures above 110 degrees C. The essential structural difference between the homo-and heterochiral crystals lies in the optimal mutual orientation of the donor and acceptor groups of the H-bonds for the former case and the unfavorable mutual orientation for the latter one.

Изучены кристаллические структуры 5-гидрокси-1-(4-метилбензил)-4-[4-фенил-1H-1,2,3-триазол-1-ил]-3-хлор-1,5-дигидро-2Н-пиррол-2-она rac-1 и 1-бензил-5-гидрокси-4-[4-фенил-1H-1,2,3-триазол-1-ил]-3-хлор-1,5-дигидро-2Н-пиррол-2-она rac-2. Обнаружена воспроизводимость однотипной гомохиральной цепочки как в хиральных, так и в рацемическом кристаллах. Проанализированы конформации молекул, вторичные взаимодействия, дополнительно сшивающие цепочку, π…π контакты между циклическими фрагментами молекул.

Подтверждено сформулированное нами ранее правило возможности спонтанного разделения энантиомеров серии тиопроизводных 5-гидрокси-3-пирролин-2-она. Проведен сравнительный анализ кристаллической упаковки трёх рацемических соединений. Обнаружен однотипный супрамолекулярный ассоциат – водородносвязанный димер, по-разному упаковывающийся в трёхмерную структуру в кристаллах.

Получены и охарактеризованы две кристаллические формы rac-1-бензил-3-бром-5-гидрокси-4-[(4-метилфенил)сульфанил]-1,5-дигидро-2Н-пиррол-2-она, а именно: рацемическое соединение (P21/c) и нормальный конгломерат (P65, P61). Показано, что конгломерат термодинамически более предпочтительный, а рацемическое соединение оказывается метастабильной формой во всем исследованном диапазоне температур. Эти две модификации образуются в виде смеси при обычной кристаллизации из раствора, характеризуются одинаковой плотностью, но их структуры существенно различаются параметрами водородных связей. Небольшая разница в свободной энергии двух фаз при комнатной температуре, определенная из данных ДСК, объясняет экспериментальную доступность обеих форм при кристаллизации из раствора. Формирование более прочной водородной связи в кристаллах конгломерата, зафиксированное методами рентгеновской дифракции и колебательной спектроскопии, может объясняться более благоприятным взаимным расположением донорной и акцепторной группировок соседних молекул в составе гомохиральной спирали по сравнению с гетерохиральным димером, который является основным мотивом в кристаллах рацемического соединения.

The physico-chemical characteristics and crystal structure of newly synthesized isobornanyl sulfoxides and sulfone are presented. After purification, diastereomeric sulfoxides were obtained in a 2:1 eutectic ratio, which did not allow either separation or enrichment of the mixture. Based on thermochemical data, the form of the phase diagram of the system was reconstructed, showing that diastereomers have significantly different melting points. According to the X-ray data, the same supramolecular open- chain S = O center dot center dot center dot H-O synthon is built up in the crystals of diastereomeric sulfoxides. The isobornanyl sulfone crystal is formed in a complex way-two crystallographically independent molecules playing different roles in the formation of H-bonds. The IR spectra of a diastereomeric sulfoxides mixture demonstrate the averaging of the synthon-forming functional groups bands. In a counterbalance, the IR spectrum of isobornanyl sulfone shows a doubling of the key bands of synthon-forming functional groups belonging to homochirally homogeneous but crystallographically nonequivalent molecules. (c) 2021 Elsevier B.V. All rights reserved.

Two crystalline diastereomorphs of rac -1-benzyl-3-bromo-5-hydroxy-4-[(4-methylphenyl)sulfanyl]-1,5-dihydro-2 Н -pyrrole-2-one are obtained and characterized: the racemic compound ( P 2 1 / c ) and the normal conglomerate ( P 6 5 , P 6 1 ). The conglomerate is shown to be more thermodynamically preferred while the racemic compound is a metastable form in the entire temperature range studied. These two modifications are formed as a mixture during routine crystallization from a solution and characterized by a similar density, however, their structures significantly differ in the parameters of hydrogen bonds. A small difference in the free energies of two phases at room temperature, which is found by differential scanning calorimetry, explains the experimental availability of both forms during crystallization from the solution. The formation of a stronger hydrogen bond in the conglomerate crystals, which is detected by X-ray diffraction and solid-state vibrational spectroscopy, may be explained by a more favorable arrangement of donor and acceptor groups of the neighboring molecules in a homochiral helix of the conglomerate as compared with a heterochiral dimer, which is the main motif in crystals of the racemic compound.