卷 508, 编号 1 (2023)

The paper presents a comparative study of the characteristics of lithium iron phosphate positive electrodes with various types of commercially available carbon nanotubes – single-walled (SWCNT), double-walled (DWCNT) and multi-walled (MWCNT). Electrochemical characteristics of the cathode materials were investigated using electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements. Cyclic stability at various current densities was estimated. The best electrochemical characteristics are exhibited by cathode materials with SWCNT (advantage over DWCNT at discharge rates higher than 10C) and DWCNT (advantage over SWCNT during prolonged cycling). During cycling at a current density of 1C, the greatest loss of capacity was demonstrated by the MWCNT-based electrode. At the same time, the electrodes with SWCNT and DWCNT demonstrated satisfactory capacity retention after 50 charge/discharge cycles: over 94 and over 98%, respectively.

The work is devoted to the development of a method for obtaining a highly sensitive composition of a controlled composition containing cationic water-soluble 5,10,15,20-tetrakis(N-Me-pyridin-3-yl)chlorine and 5,10,15,20-tetrakis(N-Me-pyridin-3-yl)bacteriochlorin. The process of diimide reduction of 5,10,15,20-tetrakis(pyridin-3-yl)porphine in pyridine and in the absence of a solvent has been studied. It is shown that the reduction in the alloy significantly reduces the reaction time (from 12 to 1.5 h) and allows to obtain compositions with a yield of up to 90%.

An interaction of 6-aryl-1,2,4-triazine-5-carbonitriles with 2‑amino-substituted thiazoles and oxazoles has been studied. The difference in the reactivity of these aminoheterocycles depending on the presence of an oxygen or sulfur atom in their composition has been demonstrated. Previously, the 4-aryl-3-hydroxy-2,2'-bipyridines were obtained as products of aza-Diels–Alder reaction between 6-aryl-3-(2-pyridyl)-1,2,4-triazine-5-carbonitriles and 2-amino-4-aryloxazoles. In the present work we have shown that the reaction of 6-aryl-1,2,4-triazine-5-carbonitriles with 2-aminothiazoles led to the products of ipso-substitution of cyano-group. The aza-Diels–Alder reaction of these compounds with 2,5-norbornadiene allowed to obtain (2,2'-bi)pyridines with the thiazol-2-amine moiety at alpha-position.

The concept of a complex catalytic processing of organochlorine production wastes using self-organizing nickel-based catalysts is proposed. Using 1,2‑dichloroethane as a model compound, the process of carbon erosion of a bulk Ni‑Cr alloy with the formation of dispersed particles catalyzing the growth of carbon nanofibers has been studied. This approach was found to be versatile and applicable for the processing of multicomponent mixtures of chlorine-substituted hydrocarbons, including the real wastes of polyvinyl chloride production. The prospects of using the carbon nanomaterial obtained from chlorine-containing waste to produce polymer composites are discussed.

The effect of cucurbit[7,8]urils on absorption and luminescent properties of bis-thiacarbocyanine (bis-TCC) based on 3,3'-dimethylthiacarbocyanine perchlorate (TCC) has been studied in water. The existence of two forms of bis-TCC which absorb in the long-wavelength and short-wavelength regions of the spectrum has been established. The properties of the form absorbing in the long-wavelength region are similar to that of the monomer of TCC (monomeric form), whereas the form which absorbs in the short-wavelength region exhibits the properties of a non-fluorescent dimer of TCC (dimeric form). The influence of cucurbit[7,8]urils manifests itself in shifts of the band maxima in the absorption and fluorescence spectra as well as in increase in the fluorescence intensity of the monomeric and dimeric forms, and also in the presence of thermally activated delayed fluorescence of the dimeric form in deoxygenated solutions at room temperature. Results obtained from the spectral and luminescent properties indicate the ability of bis-TCC to form complexes with cucurbit[7,8]urils.

For 36 3-hydroxymaleimide derivatives energies of enol and keto forms were calculated by DFT method. The results clearly show that with only few exceptions, enol form is energetically more favourable by 16–60 kJ mol^–1, with energy difference depending on 4-substituent. Global electrophilic index was calculated for all the compounds in question, showing that keto form is generally more electrophilic, with electrophilicity strongly dependending on 4-substituent. Two possible structures of hydroxymaleimide anion were evaluated, with deprotonated oxygen atom being the most energetically favourable.