卷 68, 编号 2 (2019)

The review concerns the synthesis, structure, and chemical transformations of mercury derivatives of various polyhedral boron hydrides (carboranes, metallacarboranes, and boranes) and covers a period of time since the pioneering studies of Prof. V. I. Bregadze on chemistry of C- and B-substituted derivatives of icosahedral carboranes C₂B₁₀H₁₂ up to date. The emphasis is placed on recent results obtained in this field, in particular, Hg-promoted substitution in nido-carboranes as well as the synthesis and properties of mercury derivatives of monocarbon carborane anion [CB₁₁H₁₂]^–.

The spatial and electronic structure of a series of pyridyl-containing phospholanes, which are potential ligands for the synthesis of luminescent transition metal complexes, was studied using Raman, IR and UV spectroscopy in combination with quantum chemical calculations. A series of model 1-(pyridin-2-yl)phospholane derivatives with various substituents in the pyridyl fragment was considered. Correlations between electronic structure, spectral characteristics, as well as position and nature of substituents were revealed. The obtained results can be used for rational design of complexes with specified optical properties.

A mechanochemical method for synthesis of triethoxysilane from silicon-copper contact mass and ethyl alcohol in the developed vibration reactor is presented. It is shown that the process of a direct alkoxysilane synthesis in the vibro-boiling layer is affected by a series of control parameters such as the ratio between the contact mass and the mass of grinding bodies, the grinding body sizes and their ratios in a polydisperse mixture, power density. Optimization of these parameters allowed us to obtain HSi(OEt)₃ with a selectivity of 50% at a silicon conversion of 90% without the use of promoters.

The reactions of mixed ylides containing a diazonium fragment and an "onium" group of different nature with nucleophiles were studied. In the iodonium-diazonium and sulfoniumdiazonium ylide, the nucleophile first of all substitutes the iodonium and sulfonium group. A series of hetaryl-substituted phosphazines was obtained by a one-pot process of nucleophilic substitution in a diazonium-iodonium ylide with subsequent nucleophilic addition of triarylphosphine at the diazo group.

Li-rich layered oxides Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ were synthesized by modified Pechini method using various compositions of the reaction mixture. Difference in the electrochemical performance of cathodes on their basis is explained by different morphology and microstructure of the materials. The porous hierarchical structure favors a better electrochemical performance. The presence of defects, including crystal twins, in the samples is considered to be a major reason that leads to their poor cyclability and rate capability.

Systematic data on the aggregation behavior of novel 3-hydroxypiperidinium surfactants in aqueous solutions were obtained. The ability of the surfactants to solubilize hydrophobic compounds, including the Orange OT dye and biologically active flavonoid quercetin, was characterized. The maximally achieved limiting content of these substances in micellar solutions of 3-hydroxypiperidinium surfactants is by two to three times higher than that in solutions of their non-functionalized analogs. The solubility of quercetin depends on the pH of the medium, and the highest effect observed on going from water to micellar solutions of the studied surfactants reaches two orders of magnitude.

The aggregation characteristics of binary systems based on a novel pyrrolidinium surfactant with the hexadecyl hydrocarbon tail and hydroxyethyl fragment at the nitrogen atom were studied in the presence of polyacrylic acid by a complex of physicochemical methods (tensiometry, conductometry, dynamic light scattering, fluorescence spectroscopy, and spectrophotometry). The formation of surfactant–polyelectrolyte complexes leads to a decrease in the concentration thresholds of aggregation by an order of magnitude to form aggregates ~70 nm in size was established by tensiometry and fluorimetry. The solubilization capacity of the formed mixed aggregates was tested using the Orange OT hydrophobic dye.

The effects of high hydrostatic pressure, temperature, and solvent on the rates of reactions of tetracyanoethylene (1) and 4-phenyl-1,2,4-triazoline-3,5-dione (2) with 3,4-dihydro-2Hpyran ( 3) were studied. The X-ray diffraction analysis showed that the reaction of compounds 1 and 3 occurs with the formation of the cyclobutane adduct. The reaction is characterized by enhanced entropy and activation volume, as well as a high influence of the solvent polarity (E_T) on the rate (R = 0.975). The course of the reaction 2 + 3 differs sharply from the reaction 1 + 3 by the values of entropy and activation volume, the absence of the effect of the solvent polarity on the rate, and the presence of mono-, di-, and trimeric reaction products. Possible routes of these reactions are considered.

A series of new trichloromethyl- and alkoxy-substituted pyrido[2,3-d]pyrimidine derivatives were obtained from trichloromethyl-substituted pyrimidines with vicinal amino and acyl groups synthesized based on the reaction of trichloroacetonitrile with β-diketone diaminomethylidene derivatives.

Previously unknown tetradentate ONNO-type ligands 1–5 (4,7-di(4-R´-phenoxy)-2,9- di(HOCR₂CH)-1,10-phenanthrolines (R´ = Me, R–R = –(CH₂)₅– (1), R = Me (2), R–R = 2,2-adamantylene (3); R´ = But, R–R = –(CH₂)₅– (4), R = Me (5)) were synthesized by sequential treatment of 2,9-dimethyl-4,7-di(4-R´-phenoxy)-1,10-phenanthrolines 6 (R´ = Me) and 7 (R´ = Bu^t) with excess LDA and appropriate dialkyl ketone. The structure of compound 4 was determined by single-crystal X-ray diffraction. Previously uncharacterized phenanthroline 6 was synthesized by the treatment of 4,7-dichloro-2,9-dimethyl-1,10-phenanthroline with excess p-cresol in the presence of KOH. The reaction of compounds 1–5 with one equivalent of Lappert´s germylene or stannylene, M[N(SiMe₃)₂]₂ (M = Ge, Sn), gave the corresponding germylenes 8–12 (M = Ge, R´ = Me, R–R = –(CH₂)₅– (8), R = Me (9), R–R = 2,2-adamantylene (10), R´ = Bu^t, R₂ = –(CH₂)₅– (11), R = Me (12)) and stannylenes 13–17 (M = Sn, R´ = Me, R–R = –(CH₂)₅– (13), R = Me (14), R–R = 2,2-adamantylene (15), R´ = Bu^t, R–R = –(CH₂)₅– (16), R₂ = Me (17)) in satisfactory yields. According to ¹H, ¹³C, and ¹¹⁹Sn NMR data, the synthesized stannylenes are monomeric in solution, and the tin atom has a coordination number of 4. In the series of the compounds under consideration, stannylene 16 proved to be the most active initiator for e-caprolactone polymerization, whereas the germylenes were shown to be inactive in this process.

Polymeric aggregates (~100 nm) based on polydiacetylenic acid doped with the luminescent Tb^III complexes with the tetra- and bis-1,3-diketonate derivatives of calix[4]arenes with nonyl substituents at the lower rims are considered as potential nanosensors. The obtained colloidally stable mixed aggregates can generate a substrate-induced luminescent response in aqueous solutions of 2,2´,6´,2´´-terpyridine in the micromolar concentration range due to the coordination of the latter by Tb^III ions on the aggregate surface.

The formation of stable complexes of pectin polysaccharides with 1-(2-hydroxyethyl)-4,6- dimethyl-1,2-dihydropyrimidin-2-one (Xymedon drug) was shown by UV and IR spectro scopy, dynamic light scattering, and polarimetry. The stoichiometry of the complexes was determined, and their synthesis conditions were optimized. Specific features of the thermal decomposition of pectin and synthesized complexes with Xymedon were studied by the TG/DSC method. The results obtained allow one to substantially extend ranges of using Xymedon in medicine.

4-(2-Chloroethoxy)phenyl (CEP) aglycon belongs to the class of Janus aglycons and has already been used as a pre-spacer in the synthesis of neoglycoconjugates and as a temporary protective group in the synthesis of oligosaccharides. In the present work, a set of glycosides of various monosaccharides containing CEP aglycon was synthesized. The possibility of modification of CEP aglycon was demonstrated using the corresponding lactoside as an example.

A DNA sensor was developed on the basis of glassy carbon electrode coated with polymeric forms of thionine and Azure B. Introduction of carbon black and pillar[5]arene into the electrode composition increases the efficiency of polymerization and the oxidation peak currents of dyes due to the mediating effect of the macrocycle. The addition of DNA onto the sensor surface and into the reaction mixture differently influences the electrochemical activity of poly(Azure B) and polythionine. The control of changes in current-voltage characteristics allowed us to identify the heat denaturation of DNA and its oxidation by reactive oxygen species generated upon the reaction of hydrogen peroxide and copper(II) salt. The DNA sensors can find application in the diagnosis of DNA damage on exposure to carcinogens and in screening of cytotoxic anticancer drugs.

A new method for the preparation of 2,3,4,5-tetraphenyl-1-octyl-1-monophosphole was developed. It was shown that the reaction of n-octyl chloride with a mixture of sodium 1,2,3-tri-and 1-monophospholides obtained by refluxing sodium polyphosphides with diphenylacetylene resulted in the formation of exclusively 1-n-octyl-1-monophosphole. The photophysical properties of 1-n-octyl-1-monophosphole were studied by electron absorption and emission spectroscopy. According to the Raman spectroscopy data, the phenyl moieties of this molecule are efficiently conjugated with the diene system of the heterocycle leading to the appearance of the corresponding absorption and emission bands in the visible spectral range.