Russian Chemical Bulletin最新文献

The selective monochlorination of 2,3,4-trisubstituted pyrroles was performed by a two-step one-pot method. It involves the oxidative chlorination of pyrrole substrates with trichloroisocyanuric acid giving dichlorinated non-aromatic intermediates followed by their reduction with tin(ii) chloride or sodium dithionite to afford the target products in yields of up to 100%.

The cohydrogenation of carbon oxides in the presence of complex oxides with the perovskite structure GdFe_1−xCo_xO₃ (x = 0, 0.5, 1) was studied. The catalyst samples were synthesized via the sol—gel technology and characterized by XRD, XPS, FT-IR spectroscopy, N₂ adsorption, TG, and DSC. The iron-containing samples demonstrated a high catalytic efficiency in the hydrogenation of simulated biosynthesis gas to light hydrocarbons. An increase in the carbon dioxide content in the reaction mixture to the ratio CO₂/[CO + CO₂] = 0.5 suppressed methane formation and favors the synthesis of light olefins. The hydrogenation of CO₂ proceeds in two steps: the reverse water gas shift reaction to form CO followed by CO hydrogenation to yield olefins and paraffins. The tandem effect of Fe and Co enhances the selectivity for light olefins. These findings provide valuable information useful for the rational design of efficient bimetallic catalysts for biosyngas hydrogenation.

The effect of the average nanocrystal size on the contribution of doping ion phosphorescence and band-to-band delayed fluorescence to the total photoluminescence of colloidal quantum dots of indium phosphide doped with manganese and coated with a thin zinc sulfide shell was studied by measuring excitation—emission matrices and time-resolved luminescence spectra. It was shown that it is possible to create a luminophore with a controlled luminescence lifetime on the basis of this system; however, at present, this is hampered by high polydispersity of the synthesized samples.

This review covers experimental data acquired on the interconversion of two forms of nitric oxide (NO) that is a universal regulator in biological processes: dinitrosyl iron complexes (DNICs) containing thiol ligands and S-nitrosothiols (RS—NO). This inter-conversion may lead to the occurrence of self-sustaining chemical system in living organisms, maintaining the transportation of DNICs, RS—NO, NO, and NO⁺ in cells and tissues in an autowave mode. Concepts from a novel branch of chemistry, viz. the spin chemistry, one among the founders of which is Academician A. L. Buchachenko, were used herein.

The thiolation of iodobenzene and several (hetero)aryl halides using commercially available non-immobilized copper and copper oxide nanoparticles as catalysts was studied. Almost quantitative yields of diaryl sulfides were achieved using thiophenol and copper nanoparticles with an average size of 25 nm (5 mol.%) under optimized conditions (DMSO, 110 °C, Cs₂CO₃, the reagent concentration was 0.5 mol L⁻¹). Different-size and different-composition nanoparticles were compared with microsized Cu₂O and CuO or CuI powders in terms of efficiency; the nanoparticles showed a higher efficiency. It is demonstrated that copper nanoparticles can be recycled once in the reaction of iodobenzene with thiophenol without a yield decrease. The reaction was found to have an induction period and, according to the data on copper leaching during the reaction, the highest degree of leaching was at the initial stage and leaching strongly diminished by the end of the reaction. It is also shown that the solution still exhibits the catalytic activity after the reaction has been carried out. The obtained data suggest the main contribution of homogeneous catalysis. The transformation of nanoparticles in the course of the reaction was further studied by transmission electron microscopy.

A method was developed for the synthesis of new carbazole—adamantan-1-amine conjugates with polyether linkers.

The synthesis of new (E)-2-[cyano(aryl)methylene]benzofuran-3(2H)-ones by oxidation of 4-(2-hydroxyphenyl)-4-oxobutanenitriles with the SeO₂/Et₃N/PrⁱOH system followed by the intramolecular Michael addition was elaborated.

More than ten individual higher trifluoromethylfullerenes C₇₀(CF₃)_2n (2n = 14–20) were isolated by tandem HPLC and then characterized spectrally and/or structurally. The structures of seven of them were determined and spectral information for two previously structurally characterized compounds was supplemented. The kinetic model for prediction of the isomeric composition of fullerene trifluoromethylation products was verified. It was demonstrated that intermediates with the relative formation energies to 40 kJ mol⁻¹ and the isomerization processes should be taken into account. The electrochemical behavior of one isomer of C₇₀(CF₃)₂₀ was studied. The electron-withdrawing properties for the first time structurally characterized compounds were assessed using density functional quantum chemical calculations. It was found that per(trifluoromethyl)fullerenes C₇₀(CF₃)₂₀ show a complicated behavior upon electron capture, which suggests that the relaxation processes following ionization of these isomers with noticeably different electron-withdrawing abilities are different.

Two mononuclear coordination compounds of manganese(ii) and iron(iii) with N′-(5-chloro-2-hydroxybenzylidene)-4-nitrobenzohydrazide (H₂L), [Mn(HL)(H₂O)-(DMF)Cl] (1) and [Fe(L)(H₂O)(DMF)Cl] • DMF (2), were synthesized and characterized. According to the single-crystal X-ray diffraction data, both compounds have a similar ligand composition, although in the manganese(ii) complex, the acylhydrazone is coordinated in the single deprotonated form (HL⁻), whereas this ligand in the iron(iii) complex is fully deprotonated (L²⁻). The metal atoms have a distorted octahedral coordination environment, but with different orientations of the ligands relative to the acylhydrazone plane. The crystal structures of both complexes are stabilized by systems of hydrogen bonds and π—π-stacking interactions between the aromatic moieties.