Том 479, № 2 (2018)

New vanadatogermanates Ca_3–xMe_{2 + x}V₂GeO₁₂, Ca₃Mе₂VGe₂O₁₂, and Ca₃Me₂Ge₃O₁₂, where Me = Mg, Mn, Co, Ni, Fe, Zn, and x = 0–1, have been synthesized through coupled substitutions of cations in the initial garnets Ca_2.5Mn₂V₃O₁₂ or Ca₃Fe₂Ge₃O₁₂. The unit cell parameters of the synthesized samples have been determined. Probability analysis of the cation distribution in the octahedral positions of the crystal lattice as a function of crystallographic radii has been performed taking into account the spin state of the cations.

Quantum chemical calculations by the density functional theory method at the B3LYP/6-311++G** level have shown that 5-nitro-5-methyl-1,2,3,4-tetramethoxycarbonylcyclopentadiene (1) and 5-nitro-2-methyl- 1,3,4,5-tetramethoxycarbonylcyclopentadiene (2) undergo interconversion by consecutive 1,5-sigmatropic shifts via the formation of an unstable isomer, 5-nitro-1-methyl-2,3,4,5- tetramethoxycarbonylcyclopentadiene (3), rather than through the NMR-detected 1,3-shift of the nitro group over the cyclopentadiene ring perimeter. According to calculations in the gas phase, isomer 3 is by ΔE_ZPE of 3.6 kcal/mol less stable than isomer 1, while the activation barrier of the stepwise 1 → 2 process is 24.5 kcal/mol, which agrees well with NMR data (ΔG_25C^≠, chlorobenzene, 26.5 kcal/mol).

Aromatic azido derivatives of p-tert-butylcalix[4]arene have been obtained for the first time using copper-catalyzed nucleophilic aromatic substitution of azide anion for bromide in 5,11,17,23-tetrabromo- 25,26,27,28-tetrabuthoxycalix[4]arene in a dioxane–water (3: 1) solvent mixture with N,N-dimethylethylenediamine as a stabilizing ligand for copper(I). When the reaction is carried out under with microwave heating, partial substitution products (mono-, distally di-, proximally di-, and trisubstituted) can be isolated in satisfactory yields.

Two methodologies for developing a specialized ontology for chemical technology of reagents and special-purity substances were proposed. One of them is a methodology for developing the structure and conceptual content of a specialized ontology for the chemistry and technology of production of reagents and special- purity substances. The other is a methodology for using the specialized ontology in interactive intelligent systems for semantic processing of science and technology texts.