Konstantin A. Potekhin

The reaction of 2,4-diacetyl-5-hydroxy-5-methyl-3-phenylcyclohexanone-1 with phenylhydrazine is conducted, and the crystal structures of its products, 1-(6-hydroxy-3,6-dimethyl)-2,4-diphenyl-4,5,6,7-tetrahydro-2H-indazol-5-yl)ethane-1-one and 1-(2-hydroxy-2-methyl-6-phenyl-4-(2-phenylhydrazono)-5-(1-(2-henylhydrazono)ethyl)cyclohexyl)ethane-1-one, are determined by single crystal XRD.

New multicomponent condensation of dimedone, benzaldehyde, acetacetic ester, and allylamine in the 1:2:1:1 molar ratio respectively is revealed. It proceeds with the formation of ethyl-3(allylamino)-9,9-dimethyl-7,11-dioxo-1.5-diphenyl-spiro[5.5]undec-2-en-2-carboxylate whose crystal structure is determined by single crystal X-ray diffraction.

The reaction of diethyl-4-hydroxy-4-methyl-2-phenyl-6-oxocyclohexane-1,3-dicarboxylate with Nisobutylethylenediamine is performed and the crystal structure of this reaction product (diethyl-1-isobutyl-9-hydroxy-9-methyl-7-phenyl-1,4-diazaspiro[4,5]decane-6,8-dicarboxylate) is determined by X-ray crystallography.

Single crystal X-ray diffraction is used to determine the crystal and molecular structure of 4-trifluoro-2-[2-(4-fluorophenyl)hydrazine-1-ylidene]-1-(thiophen-2-yl)butane-1,3-dione. Crystallographic data for C₁₄H₈F₄N₂O₂S are as follows: a = 8.2723(6) Å, b = 9.3009(7) Å, c = 9.9895(7) Å; α = 79.224(2)°, β = 75.851(2)°, γ = 72.337(2)°. Triclinic crystal system, P-1 space group, d _x = 1.622 g/cm³, V = 704.83(9) ų, μ = 0.286 mm⁻¹, crystal size 0.30×0.20×0.20 mm, R1 = 0.0891, wR2 = 0.1989.

A version of a computer nanoscope is proposed for single crystals with the known atomic structure for a detailed analysis of surface coordination bonds forming on nanosized nuclei due to the intermolecular interaction. Different stages of the study of rhombic and monoclinic sulfur (from the atomic/molecular structure on the first stage to the model packing growth polyhedra on the final stage) are analyzed. The calculation results of the coordination numerical sequences revealed in the computer experiment when the coordination spheres are filled with S₈ molecules with the formation of rather large molecular clusters with a size of about 10 nm or more are presented.

A nickel(II) complex with 4,4,4-trifluoro-1-(2-thienyl)butane-1,3-dione and dimethyl sulfoxide, [Ni(C₈H₄F₃O₂S)₂(C₂H₆OS)₂], was obtained and examined by X-ray diffraction. The crystals are monoclinic: a = 7.557(2) Å, b = 17.854(3) Å, c = 10.470(2) Å, β = 106.412(3)°, V = 1355.1(4) ų, ρ_calcd = 1.611 g/cm³, Z = 2, space group P2₁, R = 0.032. The coordination polyhedron of the nickel atom is a distorted octahedron consisting of four equatorial O atoms of two β-diketonate ligands and two axial O atoms of DMSO. The average Ni-O_ax and Ni-O_eq distances are 2.083(2) and 2.019(2)Å, respectively. The crystal structure is built from the discrete mononuclear complexes [Ni(C₈H₄F₃O₂S)₂(C₂H₆OS)₂] linked only by van der Waals contacts.

The 3-[4-fluorophenylazopentandion]-2,4 reagent is synthesized based on acetylacetone, and its crystal and molecular structure is studied by X-ray diffraction. It is found that [C₁₁H₁₁N₂O₂F] crystals 1 belong to the monoclinic symmetry, C2/c space group. The unit cell parameters of 1 are a = 18.827(3) Å, b = 12.839(2) Å, c = 26.475(5) Å, β = 104.834(2)°. The analysis shows that the reagent is present in the solution as well as in the crystal. A comparative analysis of these three structures with the reported data is carried out.