Glycidyl azide polymer (GAP) is a next-generation energetic binder that has garnered significant attention for applications in the aerospace industry owing to its high heat of combustion, high specific impulse, low sensitivity to detonation, low glass transition temperature, and excellent compatibility with energetic oxidizers. In the present study, the synthesis of GAP was optimized using a two-step procedure, involving solvent-free polymerization of epichlorohydrin (ECH) and subsequently aqueous azidation using phase-transfer catalyst TBAB in water with a high yield of 95
Optical, electrical, and geometric specifications of one-dimensional (1D) nanostructures, including nanorods, have transformed optoelectronic procedures. This paper discusses the application of nanorods in enhancing solar cells, LCDs, photodetectors, and displays. This shows that the ways to alter optical and electrical properties for various applications are possible. The review highlights advances that have taken place with these nanostructures in luminescent optoelectronics, such as enhancement in photoluminescence, improvement in charge carrier mobility, and localized surface plasmon resonance. The demonstration of their extensive use in energy harvesting, sensing, and high-resolution displays is mentioned as a major finding. Nevertheless, such obstacles as scalability, stability, and environmental impact still exist, and large-scale implementation is a challenge. To address these challenges, new strategies in the field of surface modification and integration of materials have been reported. Based on a comprehensive literature review, several experimental studies, synthesis innovations, and device integrations were reported. The review, by using correlation between nanorod structural and functional characteristics and device performances, presents paths to the optimization of optoelectronic efficiencies and durabilities. The findings underscore the possible game-changing potential of nanorods in optoelectronics, culminating in a new breed of energy-threatening, miniaturized, and flexible devices. Accordingly, the review provides the framework for future studies, where interdisciplinary studies are necessary to harness the potential of nanorods as next-generation optoelectronics.
The study of 2,2′-bipyridine-like ligands for the creation of sensors for zinc(II) ions was carried out, including for use in biological systems, for which the range of available sensors is currently limited. New derivatives of quinazolin-4(3H)-one and 1,3,4-oxadiazole containing a tripicolylamine moiety were synthesized. Photophysical properties of both these 2,2′-bipyridine-like ligands and their complexes with zinc(II) ions were studied. 2-Substituted quinazolin-4(3H)-one showed itself as a typical PET sensor for zinc cations; a significant increase in the luminescence of an acetonitrile solution was observed upon the addition of zinc(II) perchlorate (from <0.1 to 30.7
The effect of citric acid on the self-organization processes in aqueous solutions containing L-cysteine and silver citrate has been studied using viscometry, UV-Vis and FTIR spectroscopy, and dynamic light scattering. It has been shown that the introduction of citric acid accelerates self-organization and leads to the formation of nanoparticles and supramolecular complexes of the Ag0/Ag+/Cys type. It has been found that these systems form a silver nanoparticle sol with particle sizes ranging from 15 to 50 nm and a zeta potential of approximately 75 mV. The degree of dissociation of silver citrate and the concentration of citrate anions play a key role in the self-organization mechanism. An increase in the content of citrate anions promotes the growth of the hydrodynamic diameter of particles (up to 80–170 nm) and the formation of micron-sized aggregates, which is confirmed by zeta potential data (5–35 mV). These results are important for understanding the mechanisms of nanostructure formation based on biomolecules and metal ions and can be used in the development of new functional materials.
Gold nanoparticles (GNPs) containing fluorescent labels are in high demand for the development of disease diagnostics, including cancer. A key challenge in this field is that GNPs are effective fluorescence quenchers, which dramatically reduces the detection sensitivity of flow cytometry and fluorescence bioimaging. This is particularly relevant for fluorescein, whose emission wavelength is lower than the plasmon resonance wavelength of GNPs. However, no studies are available addressing methods for overcoming its quenching upon adsorption onto GNPs. We propose an approach for covalently attaching fluorescein to GNPs via an optimized linker –PEG71–NH–(CH2)6–NH–, which allows the GNPs and fluorophore to be separated by the distance necessary to overcome the quenching effect. The method involves modifying GNP-S-PEG-COOH with hexamethylenediamine, followed by the addition of a fluorophore in the form of a succinimide ester. Fluorescent GNP-based conjugates with diameters of 12.7 and 6.1 nm (GNP-Flu-13 and GNP-Flu-6, respectively) capable of efficient cell penetration, were synthesized. All intermediate products and the target GNPs, Flu-13 and Flu-6, were characterized using dynamic light scattering, optical spectroscopy, transmission electron microscopy, and gel electrophoresis. The developed fluorescent GNP conjugates can be effectively used for in vivo tumor tissue bioimaging.
Oil contamination of soil is a common problem in many countries. This article focuses on comparing phyto- and phytobioremediation methods for the degradation of oil in soils. A laboratory simulation of the remediation of oil-contaminated soils was conducted to study the potential of phyto- and phytobioremediation for the removal of saturated petroleum hydrocarbons (SPH). Phytoremediation was performed using the plant Anthriscus cerefolium (L.), and phytobioremediation was performed using the plant Anthriscus cerefolium (L.) and hydrocarbon-oxidizing bacteria of the genus Rhodococcus isolated from formation waters of the Samotlor oil field. Control plots without plants or microorganisms were also included for comparison. After collecting plant samples, the soil was extracted with chloroform. The SPH fraction was isolated from the resulting bitumoids using liquid chromatography and then analyzed using gas chromatography–mass spectrometry. The results obtained showed that after 55 days of plant growth, 19
The current research focuses on studying the interaction of 2-amino-4-aryloxazoles with 5-unsubstituted 3,6-di(hetero)aryl-1,2,4-triazines capable of undergoing nucleophilic substitution of hydrogen. Previously, our research group has demonstrated that 2-amino-4-aryloxazoles act as dienophiles in [4+2] cycloaddition reactions with 1,2,4-triazines. In the present study, it has been found that, under high-temperature conditions, reactions with 5-unsubstituted 1,2,4-triazines proceed in a fundamentally different manner: 2-amino-4-aryloxazoles act as C-nucleophiles. These reactions afford two types of products: (Z)-2-(1,2,4-triazin-5-yl)ethen-1-amines, formed via elimination of isocyanic acid from intermediate σH-adducts, and 5-(1,2,4-triazin-5-yl)-1,3-oxazol-2-amines resulting from direct C–H/C–H functionalization. When 2-amino-4-arylthiazoles are employed, no thiazole ring opening occurs and exclusively C–H/C–H coupling products are obtained. The σH-adducts have been synthesized and fully characterized, and for some of them, their oxidative aromatization has been demonstrated. However, when the dihydrotriazine core simultaneously bears an aminooxazole moiety at the C5 position and a 2-pyridyl substituent at the C3 position, such aromatization does not take place. Overall, the results show that the presence of a free electron-deficient C5 position in the 1,2,4-triazine ring switches the reaction pathway with 2-aminooxazoles from inverse electron-demand Diels–Alder cycloaddition to nucleophilic substitution of hydrogen.
This study explores the sustainable valorization of spent perlite, a by-product of vegetable oil winterization, for the synthesis of silicon dioxide. Spent perlite, comprising nearly 70–76
Lyotropic liquid crystal matrices as universal carriers of hydrophilic and hydrophobic substrates are promising for biomedicine as a means of drug delivery. In recent years, intensive efforts have focused on their functionalization with various dopants, specifically carbon dots with luminescent properties, thereby enabling the creation of hybrid systems with biosensing capabilities for theranostics. For the targeted use of such systems as platforms for theranostics, information is needed on the conditions for controlling their phase states. This study presents phase diagrams of polyfunctional hybrid systems based on the nonionic surfactant tetraethylene glycol monododecyl ether, decanol, and an aqueous solution containing “yellow” carbon dots as a phosphor. The temperature and concentration parameters for controlling the supramolecular structure of the resulting hybrid media have been established. The viscosity and rheological properties of hybrid media in the regions of formation of lyomesophases and gels have been studied. Analysis of rheological curves has shown that the viscosity of lyotropic liquid crystalline phases in both types of systems—hybrids with “yellow” carbon dots and initial systems based on oligoethylene oxide—exceeds the viscosity of gel-like media. The behavior of hybrid systems C12EO4/(H2O+yCD)/dec has been analyzed within the framework of microrheological Newton, Bingham, Ostwald, Casson, and Herschel–Bulkley models. It has been revealed that the flow of hybrid lyotropic liquid crystals obeys the Casson model, and that of gel-like systems follows the Ostwald model. The work shows ways to regulate the composition and viscosity characteristics of such media, which opens opportunities for the development of effective nanosystems for drug delivery and their further use in bioimaging, theranostics, and targeting of various biosubstrates.
The growing demand for nickel and cobalt in energy storage technologies, coupled with their potential release from industrial and electronic waste, poses a significant environmental challenge that calls for the development of efficient, low-cost disposal strategies. In this context, the reuse of agro-industrial waste as adsorbents represents a sustainable alternative in line with the principles of the circular economy. In this work, the spent substrate of Pleurotus ostreatus growth on coffee pulp was studied as an adsorbent material for the removal of nickel(II) and cobalt(II) ions from water. Characterization of the spent mushroom substrate exhibited moisture, organic matter, and ash contents of 8.85, 81.80, and 9.35
Zn2+ doping of α-Fe2O3 may increase its chemical activity and, thus, its ability to adsorb organic matter. Therefore, composites of Zn2+ and α-Fe2O3 with different concentration ratios were prepared in this study, and their adsorption capacities for pyrene were investigated. The results showed that Zn2+ doped α-Fe2O3 still had the same square structure as the microstructure of α-Fe2O3, but the size of the square-shaped α-Fe2O3 changed significantly. Subsequently, the ability to adsorb pyrene was enhanced with an increase in Zn2+ content, and the maximum adsorption was 424.57 μg g–1, but the adsorption equilibrium was reached within a certain concentration range. Therefore, this study provides a new idea for further modification of α-Fe2O3, an important reference for the mechanism of action in the adsorption process, and an important theoretical and practical basis for the development of efficient materials for environmental pollution control.
Functional materials based on quantum dots are specific nanomaterials with unique sets of electronic and optical properties due to the manifestation of the quantum-size effect. Quantum-chemical simulation is an effective tool for studying the physical and chemical characteristics of the studied objects, detailed analysis of their structural features, and establishing patterns of system behavior under various external conditions. This work is aimed at assessing the possibilities of quantum-chemical study of the interactions between semiconductor zinc sulfide quantum dots and some polymers for optical materials. In this study, a quantum-chemical calculation of the molecular structure of their monomer units was performed, and a method for the simulation of the structure and electronic properties of zinc sulfide quantum dots was selected. According to the simulation results, the interactions between quantum dots and polymer samples, the influence of the polymers' nature and their functional groups on the properties of nanoparticles, the efficiency of their radiation, and the features of their application in optoelectronics were studied. A comparative analysis of the calculated and experimental data on the geometric parameters and electronic properties of quantum dots was made. The calculation results indicate the possibility of changing the band gap width of quantum dots by introducing polymers as surface agents, which affects the optical characteristics and potential application of these materials. According to the calculations, the polymer containing amino groups has the highest binding energy to the surface of quantum dots, compared to other compounds. The use of a shell made of this polymer can ensure high stability of the sizes and properties of nanoparticles and contribute to an increase in the quantum yield of the material light emission.
Heterocyclic compounds are of interest for the synthesis of pharmaceuticals, and the development of their delivery systems is of particular importance for improving the biopharmaceutical aspects of therapy. In this regard, substituted 1,2,3-triazoles are of interest, as they can bind to various enzymes and receptors, exhibiting high biological activity. Currently, 1,2,3-triazoles, as a class of N-heterocyclic compounds, due to their dual functionality, are used as both pharmacophores and linkers in molecular synthesis strategies. The paper focuses on the synthesis and properties of new europium and terbium chelates with substituted 1,2,3-triazoles TR1 and TR2. Targeted synthesis of 1,2,3-triazoles was carried out to increase solubility and improve complexation with lanthanide ions. 1,10-Phenanthroline and 2,4-pentanedione were used as sensitizing chromophore ligands. The synthesized complexes exhibit high luminescent characteristics. Cellular cytotoxicity was studied for an individual 1,2,3-triazole ligand and terbium chelate. It has been shown that bis-1,3-(4-methylcarboxyl-1,2,3-triazol-1-yl)benzene selectively acts on human duodenal adenocarcinoma cells, exhibiting a high activity of 63.0 ± 4.7 μM. This compound is not toxic to human hepatocytes. The luminescent terbium complex [Tb(AcAc)3(TR2)] does not exhibit cytotoxicity in the studied cell lines and can be used as an optical probe without a destructive effect on cells in vivo. Efficient solubilization of substituted 1,2,3-triazoles TR1 and TR2 and heteroleptic complexes in the structure of the lyotropic mesophase Pluronic P123/dimethylsulfoxide allows their use in biotic systems.
Four isomeric structures of the simplest representative of alkoxy-NNO-azoxy compounds—N-methyl-N'-methoxydiazene-N-oxide—have been studied using PBE, B3LYP, wB97XD, and wB97X density functional theory methods with different basis sets. The results confirm that the most energetically advantageous configuration of this compound is the Z conformation, where the C–(O)N=N–O–C moiety of the molecule is flat, and the oxygen atoms at the N=N double bond are cis to each other. The configuration of the N-methyl-N'-methoxydiazene-N-oxide molecule corresponding to the E conformation, where the oxygen atoms at the N=N double bond are trans to each other, is less stable. This conclusion also applies to structures corresponding to two rotational mirror isomers of the Z conformation formed through the rotation of the CH3O group around the NO bond. The relative enthalpies of formation of the last three structures are about 17–18 kJ/mol higher than that of the Z conformer. Reactions of mutual transformation of N-methyl-N'-methoxydiazene-N-oxide isomers have been studied. Transition states have been found, and reaction barriers have been calculated at two temperatures, under normal conditions and at the average temperature of the existing experimental study. In addition to the above density functional theory methods, the composite G4 method was also used. All methods used in the work give consistent results. Comparison of the calculated reaction barriers of conformational transitions with the experimentally determined enthalpy of activation of the gas-phase thermal decomposition of N-methyl-N'-methoxydiazene-N-oxide enables the conclusion that the studied processes may compete with other alternative thermal degradation channels of this compound. However, the final answer in this matter can be given only after a detailed study of the secondary processes. The article is dedicated to the memory of Shamov Alexandr Georgievich.
We report the synthesis of pyrimidine-type products based on the three-component reaction between 3-nitrobenzaldehyde, ammonium acetate, and a variety of 1,3-dicarbonyl compounds in isopropanol at room temperature. This methodology is a modification of the well-documented Hantzsch synthesis, yet deviates from the generally expected dihydropyridine products, due to the change in stoichiometry. The resulting tetrahydropyrimidine products were obtained in moderate to high yields (65–83
Superhydrophobic materials have attracted widespread attention due to their unique surface structures and properties. However, in practical applications, superhydrophobic surfaces are often affected by external environmental factors, such as chemical corrosion and organic contamination, which can lead to structural damage and the loss of superhydrophobicity. In this work, SiO2@TiO2 composite micro/nano particles were prepared by coating photocatalytically active TiO2 nanoparticles onto the surface of SiO2. After modification with fluoroalkylsilane (FAS) and blending with urea formaldehyde and polyurethane, a SiO2@TiO2–FUP superhydrophobic coating with self-healing capability was fabricated. Specifically, the resulting SiO2@TiO2 micro/nanostructure exhibits excellent photocatalytic performance for the degradation of organic pollutants. As a surface modifier, 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FAS-13) provides low surface energy, which is essential for achieving superhydrophobicity. Urea–formaldehyde acts as a microcapsule shell that encapsulates the low-surface-energy compound FAS-13, enabling the coating to exhibit self-healing behaviour. Polyurethane serves as a binder that firmly anchors the hydrophobic particles and self-healing microcapsules to the substrate, thereby enhancing the mechanical durability and stability of the coating. After spray deposition, a stable superhydrophobic coating forms on the substrate surface. Even after immersion in acidic or alkaline solutions or exposure to water-flow impact, no solid particles detach from the surface, and the coating maintains its superhydrophobic properties. More importantly, the coating can restore its superhydrophobicity under UV irradiation after mechanical damage or organic contamination.
This article examines the kinetics of aluminum oxidation in sub- and supercritical water, which is of significant scientific and practical interest for producing functional oxide materials. Oxidation tests of aluminum samples in a high-pressure reactor at temperatures of 325, 350, and 375°C, followed by analysis of the mass of unreacted metal and the volume of remaining water, were experimentally carried out For mathematical modeling of the process kinetics, the Runge–Kutta–Merson method in MS Excel was used, along with macros for constructing and solving systems of differential equations based on stoichiometric matrices. A kinetic model was proposed and gradually refined, accounting for the heterogeneous nature of the process, including the stages of aluminum activation due to oxide film breakdown, the oxidation reaction itself with the formation of boehmite (2Al + 4H2O → 2AlOOH + 3H2), and the water splitting reaction (2H2O → O2 + 2H2) near the critical point. The most adequate model was described by a system of six differential equations, which considered both the chemical stages and diffusion limitations.
This study reports the synthesis of Li2O–K2O/CaO nanocatalyst via direct impregnation of discarded chicken eggshells with a mixture of LiNO3 and KNO3 at various mass ratios, followed by thermal calcination at different temperatures for varying durations at a heating rate of 10°C/min. The typical nanocatalyst (15.0 wt
The rational design of bioactive molecules is greatly accelerated by computational approaches such as molecular docking, which provide crucial predictions of binding affinity and chemical reactivity. This study aligns with this approach by exploiting these methods to predict the key properties of a novel biphenyl derivative. A combined structural characterization and theoretical investigation using density functional theory (DFT) and molecular docking were performed to predict the structural parameters, chemical reactivity, and biological activity of the compound 4,4'-dibromo-2,5-dimethoxy-[1,1-biphenyl]-2,5-dione. In terms of chemical reactivity, the lower energetic gap and higher electrophilicity index indicate that the studied compound is more chemically reactive and possesses significant electrophilic power. The in-silico study conducted using AutoDock Vina showed strong binding affinity between the compound and two proteins: dihydroxyacetanilide epoxidase (PDB ID: 2BNM) and dehydrogenase (PDB ID: 4XD2), with binding energies of –7.4 and –7.3 kcal/mol, respectively. Hirshfeld surface analysis was performed to evaluate the intermolecular interactions stabilizing the crystal structure. The results revealed that the primary contributors were O···H/H···O (27.7
The process of precursor formation for the high-entropy Fe–Ni–Co–Cu–Sn system is investigated by galvanic replacement in aqueous chloride solutions using dispersed aluminum as a reducing agent. Based on synchronized measurements of electrode potential and temperature, as well as analysis of literature data, a multi-stage process mechanism is proposed. It has been established that the galvanic replacement process can be conditionally divided into four stages. At the initial stage 1 (0–30 s) after the introduction of aluminum powder into the solution, the system is characterized by a stable potential (+0.38 V) and a constant temperature. This induction period is associated with a certain delay in the activation of the aluminum surface coated with a passive Al2O3 oxide film. The absence of heat generation directly indicates that exothermic replacement reactions have not yet begun. At the end of the induction period, the second stage begins (30–75 s), that is a sharp, two-stage drop in potential, accompanied by an explosive increase in temperature. The first stage is characterized by a rapid decrease in potential to a quasi-stationary value of about 0.0 V, due to the reduction of Fe3+ ions to Fe2+, which act as the primary oxidizer of aluminum. As soon as the local concentration of a strong oxidizing agent (Fe3+) decreases at the surface of the particle, the potential reaches a minimum of –0.38 V. The second stage corresponds to the beginning of the massive co-reduction of Fe2+, Cu2+, Ni2+, Co2+, and Sn2+ ions to form a solid precursor phase of a high-entropy alloy. The third stage characterizes the quasi-stationary state and diffusion control of the process (75–170 s). After reaching the peak of reactivity (minimum potential and maximum rate of temperature increase), the potential begins to slowly shift towards positive values up to –0.26 V, and the rate of temperature increase slows down until it reaches a maximum of 90°C. The steady-state potential is a compromise and is determined by the coupled reactions of delayed aluminum dissolution, diffusion-controlled metal deposition, and hydrogen release. At the final stage, a gradual cooling of the reaction mixture is observed at a stable potential, which indicates an almost complete depletion of oxidizing ions in the solution. Exothermic reactions cease, and the system begins to strive for thermodynamic equilibrium with the environment. X-ray fluorescence analysis confirmed the joint deposition of all five metals, the ions of which were initially present in the solution. The obtained elemental composition of the sample is close to the theoretical one for the equimolar Fe–Ni–Co–Cu–Sn system, which indicates the high efficiency of the galvanic replacement method in obtaining multicomponent precursors. Using EDS, a fairly uniform distribution of deposited metals over the surface of the particles has been established. It has been found that the accumulation and rapid release of hydrogen in the pores of particles has a mechanochemical effect on them, leading to the dispersion and formation of particles of characteristic morphology with signs of split and hollow structures.
