Russian Journal of General Chemistry最新文献

In this study, the catalytic activity of halonium and chalconium salts was explored, and special attention was focused on their application as σ-hole donating species in noncovalent organocatalysis. The catalytic performance of a series of halonium (Cl^III, Br^III, I^III) and chalconium (S^IV, Se^IV, Te^IV) salts was evaluated in the imine–isocyanide coupling, which is a key method for synthesizing biologically active compounds being one of the steps of Groebke–Blackburn–Bienaymé reaction. Analysis of the kinetic data obtained via utilization of ¹H NMR spectroscopy revealed that the iodine-based salt demonstrated the highest activity among the chosen halogen bond donors, while telluronium salt outperformed their sulfonium and selenonium counterparts in the chalcogen bond donating moiety.

The main objective of this work is the synthesis of polycyclic molecules of benzo[4,5]imidazo[1,2-a]pyrimidine hybrids by condensation of 2-aminobenzimidazole with the precursor 4-hydroxy-6-methylpyran-2-one utilizing various alcoholic solvents. Structural characterization of the synthesized compounds was conducted using diverse spectroscopic methods (NMR, MS, IR, and CHN). The formation of the obtained structures is explained by a detailed reaction mechanism.

4-Methyl-6-pyrazolyl-2-chloronicotinonitriles were synthesized by the reaction of 6-hydrazino-4-methyl-2-chloronicotinonitriles with 1,3-diketones. Upon treatment with hydrazine and methylhydrazine, 4-methyl-6-pyrazolyl-2-chloronicotinonitriles were converted into the corresponding 3-amino-4-methyl-6-pyrazolyl-1H-pyrazolo[3,4-b]pyridines. A similar reaction involving 1,1-dimethylhydrazine and ethylhydrazine was accompanied by elimination of the alkyl substituent and also led to the formation of 3-amino-6-pyrazolyl-1H-pyrazolo[3,4-b]pyridines. Acylation and carbamoylation of the prepared compounds proceeded regioselectively at the amino group. One of the new compounds, N-[6-(3,5-dimethylpyrazol-1-yl)-1,4-dimethyl-1H-pyrazolo[3,4-b]pyridin-3-yl]cyclopropanoylamide, showed a growth-stimulating effect in the field experiments on winter wheat crops.

The curing agent is an essential component in the epoxy resin (EP) system, while the rational construction of the curing agent is highly desired for practical applications. In this study, a novel curing agent was developed using Zeolitic imidazolate framework-8 (ZIF-8) and 1-ethyl-3-methylimidazolium acetate ([Emim][Ac]). [Emim][Ac]@ZIF-8 serves as both a functional filler and a curing agent for preparing [Emim][Ac]@ZIF-8/EP. The curing behavior of [Emim][Ac]@ZIF-8/EP was investigated through differential scanning calorimetry (DSC) characterizations. Notably, during the curing reaction of the epoxy resin, [Emim][Ac]@ZIF-8 exhibited delayed kinetic behavior compared to pure [Emim][Ac]. Furthermore, the impact of the loading amount of [Emim][Ac] and the dosage of [Emim][Ac]@ZIF-8 on the curing temperature of the system was explored. Finally, the curing kinetics of epoxy resin (E-51) in both [Emim][Ac]@ZIF-8 and [Emim][Ac] were analyzed using DSC at different heating rates. This work provides an insightful guidance for the construction of effective fillers for the preparation of epoxy composites.

A series of novel 1,3,4-thiadiazole sulfone-derived compounds incorporating an amide moiety was synthesized. The in vitro antibacterial activities against Xanthomonas oryzae pv. oryzae (Xoo), Xanthomonas oryzae pv. oryzicola (Xoc), and Xanthomonas axonopodis pv. citri (Xac) demonstrated that 2-(2-methoxyphenoxy)-N-[5-(methylsulfonyl)-1,3,4-thiadiazol-2-yl]acetamide exhibited remarkable antibacterial activities against all three pathogenic bacteria with EC₅₀ values of 6 μg/mL for Xoo, 11 μg/mL for Xoc, and 16 μg/mL for Xac, which were even surpassed those of bismerthiazol and thiodiazole copper. Furthermore, under greenhouse conditions at a concentration of 200 μg/mL, this compound showed superior efficacy compared to bismerthiazol and thiodiazole copper in reducing rice bacterial leaf blight with a protection activity of 53.43% and curative activity of 47.16%. To the best of our knowledge, this study presents the inaugural report on the synthesis and bioactivity evaluation of novel 1,3,4-thiadiazole sulfone-derived compounds incorporating an amide moiety.

A method was developed for the synthesis of first representative of unsymmetrical cage phosphonates containing a carbonyl group on the periphery. New hydrazones were prepared by the reaction of 3-hydroxy-4,8,9,11-tetramethyl-12H-6,12-methanodibenzo[d,g][1,3,2]dioxaphosphocine-2-carbaldehyde-6-oxide with hydrazines and hydrazides (phenylhydrazine, benzohydrazide, nicotinic hydrazide, isonicotinic acid hydrazide). Composition and structure of all the obtained compounds were confirmed by ¹H, ¹³С and ³¹P NMR, IR spectroscopy, mass spectrometry and X-ray structural analysis. Based on 1D/2D correlation NMR experiments, it was found that the resulting hydrazones exist only as E-isomer.

The reaction of unsubstituted α-nitrocinnamic nitrile with 1-methylpyrrole ends with the formation of an Ad_N product, whereas the reactions of 2-aryl-2-nitroacrylonitriles with such N,N- and N,S-binucleophiles as hydrazine, phenylhydrazine, and o-aminothiophenol lead to transformation products of the initially formed adducts, linear azines and phenylhydrazones, or to a heterocyclic benzothiazole structure.

A series of N¹-[4-(diethylamino)phenyl]-N⁴,N⁴-diethyl-N¹-(thiophen-2-yl)benzene-1,4-diamine based (D-A2-π-A) organic dye-sensitizers with enzothiadiazole (DSN dyes)/dihydrothieno[3,4-b][1,4]dioxine (DSO dyes) as auxiliary acceptor were studied, emphasizing the influence of the π bridges on the DSSC’s efficiency. DFT and TD-DFT methods at B3LYP/6-31G** were used to calculate the molecular, optoelectronic and photovoltaic properties of the dyes such as Frontier orbital energies, chemical reactivity indices, absorption wavelengths, light harvesting efficiency (LHE), electron injection driving force (ΔG^inject), regeneration drive force (ΔG^regen), open circuit voltage (V_oc) and excited state lifetime (τ_esl). The results of open circuit voltage (V_oc), light harvesting efficiency (LHE) and light electron injection driving force (ΔG^inject) show that all the dyes have good photoelectric conversion efficiency but with low dye regeneration (ΔG^regen) ability. The energy gap (E_g) has a major effect on the activity of molecules; thus, a sensitizer with a small E_g is more advantageous for electron excitation and has increased absorption properties. It was found that DSN dyes have lower E_g than corresponding DSO dyes. Therefore, DSN dyes are expected to have longer absorption wavelength (red shift) than respective DSO dyes. The DSN dyes show ease of electrons transfer through the dyes, which is linked to low values of chemical potential for DSO dyes. However, high excited state lifetime (τ_esl) values of some dyes could lead to more stability of the dyes in the cationic state for a longer time, which may result in higher charge transfer efficiency; thus enhancing electron injection efficiency of the dye sensitizers for dye-sensitized solar cell (DSSC).

Supercapacitors have attracted a great deal of interest in energy storage due to their high power density and exceptionally long cycle life. Conductive polymers, such as polyaniline (PANI) and poly (3,4-ehtylenedioxythiophene) (PEDOT), are among the most studied electroactive materials due to their excellent properties. In the present study, PANI and PANI/PEDOT:PSS composites were synthesized electrochemically for supercapacitor applications. Characterization techniques, such as X-ray diffraction, indicate the amorphous nature of PANI and PANI/PEDOT:PSS composites. UV-Vis spectroscopy was used to analyze the optical properties of PANI and PANI/PEDOT:PSS composite. The morphology of the PANI/PEDOT:PSS composite observed by scanning electron microscopy (SEM) shows the morphology of the porous structure, which enhances charge transport in the supercapacitor. The electrochemical performance of both materials was obtained in a 0.5 M H₂SO₄ electrolyte. The cyclic voltammetry study of the PANI/PEDOT:PSS composite showed the highest specific capacitance of 1265.38 F/g at a scan rate of 20 mV compared with PANI, which recorded a value of 1020 F/g at 10 mV/s. Electrochemical impedance spectroscopy with an appropriate equivalent circuit model was employed to explore the internal resistance and capacity observed for PANI and PANI/PEDOT:PSS. Electrochemical and physicochemical characterization tests showed that the composite exhibited superior electrical and structural performance, making it a suitable material for energy storage applications.

Two variants of cathelicidin-2 were designed and their antimicrobial activity and structure–function relationship were evaluated and discussed. The MICs of LH22 and VL22 against Aeromonas hydrophila were < 0.98 and 15.6 μg/mL, respectively, and the MICs of VL22 against Staphylococcus aureus and Escherichia coli were 15.6 and 31.25 μg/mL, respectively. Large amounts of nucleic acids and proteins were detected in the supernatant of culture medium after treatment with LH22 and VL22. Apparent wrinkled and distorted cell morphology and apparent pores could be observed by SEM in the treated Aeromonas hydrophila with the two peptides. These two peptides also showed the neutralizing activity against LPS.