Russian Journal of General Chemistry最新文献

Levels of PCBs were determined in Comephorus baicalensis (Pallas, 1776), a pelagic sculpin endemic to Lake Baikal. Concentrations of PCBs were measured using GC/MS. The maximum concentrations over the entire study period (2000–2023) were found for ƩPCB₍₃₁₎ (694–1669 ng/g lw). The decreasing trend of ƩPCB(31) concentrations was revealed using the Mann–Kendall test. With regard to the percentage composition of the PCBs, increasing trends were found for PCB 99, PCB 85, PCB 118 and negative trends for PCB 28, PCB 149, PCB 132, PCB 126, PCB 177, PCB 170. The results indicate that the southern basin of Lake Baikal continues to experience considerable pressure from the ongoing influx of PCBs.

The effect of synthetic detergents on leguminous crops Vigna radiata and Lens culinaris was studied in Petri dishes. After four days of incubation, measurements of the seedlings were taken. It was shown that the plants lagged in growth and development during incubation. At concentrations of 2.5 g/L and 5 g/L, L.culinaris died. At a concentration of 0.5 g/L, inhibition was almost lethal (97.6‒98.1%) in lentils. Mung showed a higher degree of tolerance to all concentrations (except for Persil Color Plus 5 g/L, 100% inhibition). Interaction with detergents may lead to a decrease in the yield of legumes.

Hydration properties of venlafaxine hydrochloride are significant in view of pharmaceutical applications. The effect of trisodium citrate salt on thermophysical properties of venlafaxine drug in aqueous solutions has been evaluated. Densities, ultrasonic velocities and refractive indices for system containing venlafaxine hydrochloride (VFH) + trisodium citrate salt (TSC) + water have been measured at 303.15 K and atmospheric pressure. The measured data have been used to calculate standard partial molar volume, compressibility and their corresponding transfer properties namely transfer volume and compressibility. The results have been interpreted in terms of different types of interactions and hydration behavior of the drug. Release of water molecules from hydration shells of the drug due to dehydration effect of trisodium citrate salt has been observed.

Two different design of conjugates of prostate specific membrane antigen (PSMA) ligands with monomethyl auristatin E were proposed. PSMA ligands were obtained using peptide synthesis approaches. The possibility of obtaining bimodal conjugates of these ligands with two equivalents of monomethyl auristatin E by the azide-alkyne cycloaddition reaction was shown. The possibility of obtaining compounds containing only one equivalent of monomethyl auristatin E in the structure by these methods was analyzed.

The review summarizes and analyzes the literature data on methods for the preparation of D,L-homocysteine-thiolactone hydrochloride and its enantiomers. Due to the lack of comprehensive reviews on the topic and the limited number of synthetic approaches, the authors considered it necessary to systematize and describe the available data on the synthetic methods for D,L-homocysteine-thiolactone hydrochloride and its enantiomers, covering the period from the 1930s onward. An assessment of productivity, reagent availability, and environmental safety of the considered methods is provided.

Resonance-assisted hydrogen bonding (RAHB), a special type of intramolecular hydrogen bond (IMHB), plays a crucial role in biological systems and exhibits significant potential in material design, biomolecular chemistryand catalytic chemistry. Due to its importance, RAHB has been extensively studied. Accurate estimation of RAHB energy is essential for understanding molecular interactions and conformational behavior. In this study, we synthesized thirty-three N-(phenylethylene)anilines (2-OH-R¹PEAR²) with varying substituents and measured their ¹H NMR chemical shift δ_H(OH) of the OH and the ¹³C NMR chemical shift δ_C(CMe=N) of the CMe=N. Using these model compounds, we calculated the hydrogen bond energy E_HB, bond lengths d_O–H and d_N···H, and the aromaticity of the phenyl rings (PDI). We investigated the relationship between the E_HB and the bond lengths (d_O–H, d_N···H) in 2-OH-R¹PEAR², the correlation between NMR chemical shifts δ_H(OH), δ_C(CMe=N), E_HB and the aromaticity of the hydrogen-bonded ring (PDI_Q). A comparative analysis was performed with structurally similar ortho-hydroxy diaryl Schiff bases (2-OH-R¹BAR²). In 2-OH-R¹PEAR², the calculated d_O–H and d_N···H values show a strong correlation. The E_HB also correlates well with d_O–H, suggesting that d_O–H can serve a reliable indicator of hydrogen bond strength. In compound 2-OH-R¹PEAR², E_HB has good correlations with δ_H(OH), δ_C(CMe=N) and PDI_Q. The introduction of α-CH₃ on the bridge bond causes the two benzene rings in 2-OH-R¹PEAR² to deviate from the coplanar more severely than in 2-OH-R¹BAR², rendering the aromaticity of ring B negligible in influencing δ_H(OH) and δ_C(CMe=N).

Based on long-term monitoring of technogenic and natural waters, this study identifies the main pollutants discharged by the Dalnegorsky Mining and Chemical Plant into the Rudnaya River: B, Mn, and SO₄^{2 –}. Experiments were conducted on a laboratory-scale model of artificial geochemical barriers to treat technogenic waters from the plant. The results demonstrate high removal efficiency not only for the main pollutants (B, Mn, SO₄^{2 –}), but also for accompanying elements (Cu, Zn, Pb) and carcinogenic elements (As, Ni, Cr, Cd). The maximum reduction was achieved using a Taurit sorbent as the barrier material at a filtrate flow rate of 0.78 × 10^–6 m³/s (0.047 L/min). This study represents the first application of artificial geochemical barrier technology for the purification of technogenic waters originating from borosilicate ore tailings.

Trophic pressure from planktivorous fish suppresses the development of large filter-feeding cladocerans, leading to their replacement by small-sized species. In a flow-through ecosystem isolated from planktivorous fish, the cladoceran population—particularly Simocephalus vetulus—increased to 4200 specimens/L. In natural ponds, large filter feeders are consumed by fish and occur only in small quantities. Zooplankton are capable of fragmenting large colonies of cyanobacteria and green algae, thereby improving food availability. Isolation of zooplankton from ichthyofauna leads to an increased proportion of large filter-feeding species.

The pollution level of the Podkumok, a nonglacial river in Central Caucasus, was assessed by comparison with the established maximum permissible concentrations of ecotoxicants NO₂^‒, NO₃^‒, and NH₄⁺ for a fifteen-year observation period; the quality class of the surface water was determined. The results of chemical analysis of the concentration levels of pollutants in the Podkumok River watercourse were used. Certain biogenic nitrogen compounds are currently equated to a number of heavy metals in terms of the negative impact they exert on aquatic ecosystems. The content of nitrogen compounds was determined using chemical analysis methods. The years of water pollution with all forms of inorganic nitrogen and their repeatability were identified. An environmental assessment of the pollution of the Podkumok River by year in the main phases of the hydrological regime, i.e., during the winter low water and summer flood periods, was provided according to the quality classification system for land surface waters. Based on the observations of the composition of the river waters in the period 2005‒2019, the levels of pollutants in the watercourse of the Podkumok River were identified.

Previously, we studied the enantioselective reduction of prochiral saturated aliphatic ketones, catalyzed by available biocatalysts, leading to the formation of the corresponding secondary S-alcohols. In this study, to investigate the synthetic potential of a biocatalyst based on the Petroselinum crispum culture, we explored the possibility of biocatalytic reduction of prochiral unsaturated aliphatic ketones, exemplified by hex-5-en-2-one and 6-methylhept-5-en-2-one, to the respective (S)-(+)-hex-5-en-2-ol and (S)-(+)-6-methylhept-5-en-2-ol, precursors in the synthesis of biologically active substances used in agriculture and medicine.