Russian Journal of General Chemistry最新文献

The use of modern chemical methods for the protection of aquatic ecosystems has become increasingly important. These methods are applied to remove toxic organic pollutants. This study presents a method for the remediation of water contaminated with toxic phenol using nanotechnology. The main objectives were: (1) to investigate the photochemical degradation of phenol by TiO₂ nanoparticles in both nitrogen-doped and nitrogen-free systems; and (2) to determine the adsorption properties of rutile-phase TiO₂ nanoparticles. Photochemical reactions were performed using TiO₂ nanoparticles with sizes ranging from 10 to 32 nm, which were synthesized via the sol-gel method. The nanoparticles were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Additionally, the adsorption behavior of TiO₂ nanoparticles was examined.

Two new anthraquinone derivatives: 1-(4-ethylpiperazin-1-yl)-5-chloroanthracene-9,10-dione and 1-(4-methylpiperidine-1-yl)-5-chloroanhtrecene-9,10-dione were synthesized in the laboratory and their structures were confirmed by Fourier transform-infrared and nuclear magnetic resonance techniques. The optimal molecular geometry was determined using a 6-311+G(d,p) basis set and the Density Functional Theory, B3LYP approach. The presence of charge transfer within the molecule was demonstrated by the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). These new anthraquinone derivatives exhibited antibacterial activity against both Gram-positive and Gram-negative bacteria. The highest antimicrobial effect was observed against Gram-positive bacteria, especially Bacillus cereus and Staphylococcus aureus. The antibacterial properties of these new anthraquinone derivatives were also demonstrated by molecular docking simulations using Escherichia coli DNA gyrase B (PDB ID: 6F86). Moreover, molecular dynamics (MD) simulations conducted over a 100 ns period verified that the 1-(4-ethylpiperazin-1-yl)-5-chloroanthracene-9,10-dione-6F86 and 1-(4-methylpiperidine-1-yl)-5-chloroanhtrecene-9,10-dione-6F86 complexes were stable. According to a combination of experimental, computational, and biological research, compounds are promising antibacterial agents that might be developed further.

This paper presents the results of a theoretical study on the host-guest inclusion complex involving the herbicide diuron in β-cyclodextrin. Diverse computational techniques were used to determine the complex structure, geometry, and stability energies. The analysis of the diuron/β-CD inclusion complex was performed both in a vacuum and in water in a 1 : 1 ratio. The DFT/B97-3C method was employed to determine the complex structures and calculate their stability energies. The specific configurations were determined using nuclear magnetic resonance spectroscopy. The interaction bonds were examined, revealing the presence of typical hydrogen bonds by AIM analysis. The interactions were further elucidated by applying non-covalent interactions (NCI). This suggests that the Van der Waals interactions and hydrogen bonds significantly contribute to the formation of the inclusion complex. The absorption and emission energies of the examined complex were determined by calculating the energy gap (EHOMO–ELUMO).

This review summarizes data on modern and known approaches to the synthesis of new and previously obtained heterocycles with an isoindole fragment. High yields of isoindole derivatives are achieved when using ortho-substituted homologs of benzoic acid as starting compounds. This review also presents several examples of approaches to the synthesis of isoindole derivatives via multicomponent reactions involving amines, aldehydes, isocyanates, and aryl carboxylic acids lacking substituents at the ortho-carbon atom. Several publications reflect the results of studies on the biological activity of these heterocycles.

CdS/MoS₂ heterostructure thin films were fabricated on glass substrates using the chemical bath deposition method. To optimize crystalline quality and enhance the light absorption of the CdS/MoS₂ heterostructure thin films, aiming to improve the visible-light photocatalytic activity, we controlled the thickness of the CdS thin film deposited on the MoS₂ thin film by changing the deposition time. The results revealed that the optimal CM15 heterostructure thin film (deposition time of 15 min, CdS thickness ~186 nm on a 28 nm MoS₂ thin film) exhibited excellent light absorption in the range of 400 to 700 nm. Furthermore, the CM15 sample demonstrated a remarkable degradation efficiency of 95.46% and a degradation rate constant (k_app) of 0.020307 min^–1 for rhodamine 6G (R6G) dye after 150 min of visible-light irradiation. This high performance can be ascribed to: (1) the improved crystalline quality of the CdS thin film grown on MoS₂ thin film, which reduced defects and minimized charge carrier trapping; (2) the band alignment at the CdS/MoS₂ interface, facilitating efficient charge carrier separation.

The aim of this study is to justify regional maximum permissible concentrations (MPC_reg) of metals in transboundary rivers. Primary hydrochemical monitoring data from archival materials of the North-West Department for Hydrometeorology and Environmental Monitoring and the Neva-Ladoga Basin Water Authority were used for the calculations. The results present MPC_reg values for five metals—iron, manganese, copper, cadmium, and lead—in the Russian waters of seven rivers: Narva, Vuoksa, Seleznevka, Serga, Utroya, Lovat, and Hiitola. Three calculation methods were applied: the method of S.A. Patin, the method of D.G. Zamolodchikov, and the method of E.V. Venitsianov et al. In Patin’s method, the average concentration of each element and the standard deviation were used. Zamolodchikov’s method employed the upper and lower quartiles of the distribution. Venitsianov et al.’s method used the sample size, the upper quartile, and the standard deviation for a quantile of approximately 0.75. Based on the principle of sanitary maximalism, the method of E.V. Venitsianov et al. was substantiated as the optimal approach for calculating regional MPCs. A “very high” correlation was observed between the MPCs of metals and their clarkes in the upper continental crust.

This study addresses the need for a quantitative assessment of the median lethal dose (LD₅₀) of caffeine in humans following oral administration. The aim was to estimate the human oral LD₅₀ by extrapolating data obtained from laboratory animals, including mice, rats, guinea pigs, rabbits, dogs, and cats. Extrapolation was performed using three approaches: the method of Yu.R. Rybolovlev and R.S. Rybolovlev, the guidelines of the U.S. Environmental Protection Agency (EPA), and the method of D.B. Laurence and A.L. Bacharach. The estimated human oral LD₅₀ of caffeine and its confidence interval are presented.

The article discusses the possibility of using the INAA method based on a ²⁵²Cf radionuclide neutron source for determining the content of Sc, In and Au in various minerals. The method was tested on samples of cassiterite, wolframite, hubnerite, chalcopyrite, and arsenopyrite, as well as galena and sphalerite (both in a monomineral samples and in their mixtures). Sc was found in the samples at concentrations ranging from 0.8 to 29 ppm in cassiterite and 21.9 to 469 ppm in wolframite (in the latter, it is 1.4 to 30 times higher than the Clarke value). Average In content (g/t): in cassiterite—17 (90 times exceeding Clarke value), in hubnerite—9 (47 times), in chalcopyrite—988 (5200 times), and in mixed sulfides—49.3 (260 times). Results for Au (g/t): in cassiterite—from 0.14 to 66.9 (exceeding Clarke value 32 and 1520 times), in hubnerite—0.28-3.82 (Clark excess 64‒870 times), and in mixed sulfides (arsenopyrite, galena, sphalerite)—0.53-4.55 (120-1034 times).

The objective of the study is to assess the dynamics of anthropogenic pressure coefficients on the territory of Russia for the period 2009‒2023. The anthropogenic pressure coefficient was calculated as the ratio of energy consumption per unit area (km²) to the corresponding world average. Over the specified period, the anthropogenic pressure trend is characterized as negative. A statistically significant relationship between the anthropogenic pressure coefficients and the dimensionless population density was established.

The article presents data on the content of perylene and other priority PAHs in the bottom sediments of the coastal part of Lake Baikal in 2024, obtained by HPLC with fluorimetric detection. The perylene concentrations in the Lake Baikal sediments ranged from 0.2 to 273.2 ng/g (dry weight). Minimum perylene concentrations were determined in inequigranular sands with low organic matter content. A higher average perylene content was found in the sediments at the BAM (77.9 ng/g, n = 18) and BPPM (72.6 ng/g, n = 30) testing sites compared to the Selenga area (25.7 ng/g, n = 13). At the BAM testing site in the northern part of Lake Baikal, the average perylene content exceeded by approximately 1.5 times the sum of priority PAHs (50.3 ng/g), by contrast to the BPPM and Selenga sites. Compared to the high correlation [Pearson correlation coefficient (PCC) > 0.75] between the sum of PAHs and organic carbon in the sediments of the surveyed sites, the relationship between perylene and organic carbon is weaker (PCC = 0.10–0.54). It was shown that high perylene concentrations can be present not only in deeper layers of bottom sediments but also in the surface layer, which can be associated with biogenic, rather than anthropogenic, origin of perylene.