Vol 93, No 2 (2023)

For the first time reactions of acetylene generated in a two-chamber reactor with methyl diazoacetate, iodine and benzoyl chlorides were studied. Methyl 1 H -pyrazole-3-carboxylate, ( E )-1,2-diiodoethylene, ( E )-1,2-dideutero-1,2-diiodoethylene, (2 E )-1-aryl-3-chloroprop-2-en-1-ones, including D-labeled 3-chloro-2,3-dideutero1-phenylprop-2-en-1-one were synthesized.

A regioselective method for the synthesis of esters of quercetin and myricetin at the hydroxy group in the 3 position was developed. As acids participating in the esterification reaction, 2-hydroxybenzoic (salicylic), 4-hydroxybenzoic, 2,6-dihydroxybenzoic, 3,4-dihydroxybenzoic (procatechuic), 3,4,5-trihydroxybenzoic (gallic) acids were used. A new series of quercetin and myricetin esters were obtained.

Solvent-free reaction of 3,6-diaryl-1,2,4-triazine-5-carbonitriles with 2-amino-4-aryloxazoles was studied. In this case, the formation of 3- and 4-aryl-substituted pyridines (two isomeric products) in yields up to 20 and 27%, respectively, was found. This result is different from that for the reaction of 3-(2-pyridyl)-1,2,4-triazine-5-carbonitriles with these substrates. Thus, in this case, 2-amino-4-aryloxazoles act as synthetic analogues of arylacetylenes.

Diarylethenes containing coumarin and thiophene substituents in the thiazole bridge and quinoline receptor fragments were synthesized. 2-Chloroquinoline diarylethenes form colored cyclic hexadiene forms under UV light, which undergo reverse isomerization when exposed to visible light. 2-Hydroxyquinoline diarylethenes are nonphotochromic. The ionochromic effects of interaction with fluoride anions and copper(II) and nickel(II) cations were studied.

The reaction of triphenylantimony with ROOH peroxides (R = t -Bu, H) and unsaturated carboxylic acids afforded triphenylantimony dicarboxylates Ph₃Sb(O₂CCH=CH₂)₂, Ph₃Sb(O₂CCMe=CH₂)₂, Ph₃Sb(O₂CCH=CHMe)₂, Ph₃Sb(O₂CCH=CHPh)₂, Ph₃Sb(O₂CCH=CHC₆H₄NO₂-3)₂, Ph₃Sb(O₂CCH=CHC₄H₃O)₂, Ph₃Sb(O₂CCH=CH-C₆H₄OMe-4)₂, Ph₃Sb(O₂CCH=CHCH=CHMe)₂, Ph₃Sb(O₂CCH₂CH=CH₂)₂, p -Tol₃Sb(O₂CCH=CHPh)₂ with yields of 35-86%. The comparison of the obtained compounds structure using the structural parameter τ (from the X-ray diffraction data), as well as the difference in the values of ν_as(COO) and ν_s(COO) (from the IR data) was investigated. In all compounds, the coordination of the antimony atom occupies an intermediate position between the trigonal-bipyramidal and tetragonal-pyramidal. In all compounds, there is an additional coordination of the antimony atom on carbonyl oxygen atoms. Intermolecular interactions in acrylate, methacrylate, crotonate and triphenylantimony sorbate with the participation of C=C double bonds of unsaturated carboxylate fragments of neighboring molecules located on top of each other were revealed. Antimony-containing transparent polymers - polymethyl methacrylate and polystyrene, which may be of practical value for the creation of new composite materials, have been synthesized on the basis of triphenylantimony dicrotonate. The molecular mass characteristics of polymers, the absorption of X-rays, UV light by the obtained polymers were measured.

The response surface methodology using three-level Box-Behnken plans was applied in order to optimize the yield of the cone and chair conformers in the synthesis of calix[4]resorcinol functionalized with 4-dimethylammoniophenyl group along the lower rim. We used data from one-factor experiments in which the temperature, reaction time, and molar ratio of HCl to the reactants of the reaction mixture were varied to plot the response surfaces. The ratio of conformers was calculated based on the analysis of ¹H NMR spectra of the products isolated from the reaction mixture. The adequacy of the proposed mathematical models for determining the yields of chair and cone conformations is confirmed by a high correlation coefficient ( R 0.99979). Optimal conditions were found for the maximum yield of the chair conformation (50°C, 2 h, molar ratio of HCl to reagents in the reaction mixture is 1-1.5, yield 100%). The optimal conditions for obtaining the cone conformation are: temperature 68.6°С, stirring time in the range of 2.24-6.44 h and the molar ratio of HCl to reagents in the reaction mixture is 2. Carrying out the synthesis under these conditions leads to the yield of the cone conformation in the range of 57.70-58.07%.

«2+1» tricarbonyl complexes [M(CO)₃(N^N)CN(CH₂)₁₀COOMe]ClO₄, where M = Tc or Re and N^N = 2,2′-bipridine (bipy) or 1,10-phernanthroline (phen), were prepared by reaction of [M(CO)₃(N^N)(MeOH)]ClO₄ with methyl 11-isocyanoundecanoate in methanol. The complexes were isolated and characterized by IR, ¹H NMR spectroscopy and elemental analysis. Stability of the «2+1» tricarbolyl complexes with respect to transchelation with histidine was studied.

A technique for the template synthesis of nanocrystalline titanium(IV) oxide and its modification with nanoparticles of gadolinium(III) oxide and silver has been developed. The composition and structure of the obtained materials were characterized by X-ray phase analysis and IR spectroscopy. The specific surface area and pore size distribution were determined. The photocatalytic properties of the synthesized TiO₂/Gd₂O₃ and TiO₂/Gd₂O₃/Ag nanomaterials were evaluated in the reaction of degradation of aqueous solutions of methyl orange upon irradiation with UV light. It was found that the introduction of gadolinium (III) oxide increases the photocatalytic activity, and the introduction of silver particles makes the photocatalyst sensitive to light with a shorter wavelength.

Ruthenium-codoped bismuth niobate Bi_1.5Cu_0.375Mg_0.375Nb_1.45Ru_0.05O_7-δ with the pyrochlore structure was obtained by Pechini method. The distribution of Ru⁴⁺ over Nb⁵⁺ sites was established by structural analysis. According to the data of optical reflectance spectra, the optical band gap decreases from 2.40 to 2.27 eV for the sample doped with ruthenium. A small amount of ruthenium in the system was found to result in an increase in conductivity by 0.5 orders of magnitude compared to Cu-Mg-substituted bismuth niobate, due to an increase in the electronic component of the conductivity.

The DFT PBE0/SDD method was used to calculate bond lengths and bond indices in As₂₀, Ni₁₂As₂₀, [As@Ni₁₂As₂₀]^3-, As@C₆₀ and As@C₇₀ clusters. The degrees of oxidation and reduction of the endo -atom and the shell are expressed in terms of the populations of one-electron states localized in these components of the complexes. Each As atom in clusters has a entirely localized lone electron pair. The arsenic atom inside fullerenes retains the electronic configuration and spin of the ground state of the free As atom. Inside the [Ni₁₂As₂₀]^6- shell, it has an oxidation state of 3+. There is no covalent bond between the endo -atom and the shell in clusters. The bond indices refute the opinion about the “onion” structure of [As@Ni₁₂@As₂₀]^3-: the nickel atoms are not bonded to each other, the As-As bond indices are three times lower than in As₂₀.