Journal of Structural Chemistry最新文献

A new highly lipophilic glycoluril, 1-(1-carboxyheptylidene)-5-octyl-2,4,6,8-tetrahydroazabicyclo[3.3.0.] octane-3,7-dione (I), is prepared by the interaction of 9,10-diketostearic acid and urea in solution and in melt in the presence of methanesulfonic acid. The obtained compound is characterized by ¹H, ¹³C NMR, and IR spectroscopy; its crystal structure is determined.

We present the results of the synthesis and analysis of a series of organic-soluble cluster complexes of molybdenum: (Bu₄N)₂[Mo₆X₈L₆] (X = Br, I; L = –CH₂=CH–COO^– (acrylate, Acr^–) and –CH₂=C(CH₃)–COO^– (metacrylate, MAcr^–)). The complexes are obtained by interacting (Bu₄N)₂[Mo₆X₈X₆] with silver salt of the respective acid. The mentioned compounds are characterized in detail by powder and single crystal X-ray diffraction, elemental analysis, IR and NMR spectroscopy. The luminescent properties and photophysical parameters of the solid cluster complexes are studied.

Peroxosolvates of the following heteroaromatic carboxylic acids are prepared and structurally characterized: (R,S)-2,2′-bipyridine-3,3′-dicarboxylic acid 1,1′-dioxide C₁₂H₈N₂O₆·H₂O₂ (1) and a quinolone antibiotic oxolinic acid C₁₃H₁₁N₁O₅·H₂O₂ (2). In both solvate structures, peroxide molecules participate only in two HOOH⋯O hydrogen bonds with very strong proton-acceptor groups of coformers: oxygen atoms of pyridone and N-oxide groups. The same O atoms form strong hydrogen bonds with carboxyl groups. The possibility of preparing crystal adducts of H₂O₂ with acidic coformers is confirmed.

In this study, ethyl 2-(2-((ethoxycarbonyl)amino)thiazol-5-yl) acetate (4) was obtained by reacting ethyl 2-amino thiazol-4 acetate (1) and different hydrazine carboxylate derivatives (2) via an acylation route different from the synthesis plan. The spectra of the synthesized ethyl 2-(2-((ethoxycarbonyl)amino)thiazol-5-yl) acetate (4) were examined and its structure was determined. FTIR, ¹H NMR, ¹³C NMR and Mass spectra were recorded, and structural analyses were completed by using these spectral data. Studies on the structure of compound 4 support its synthesis as a product of an acylation reaction. Crystal structure studies on compound 4, including structural X-ray study, theoretical DFT calculations, Hirshfeld surface analysis and molecular docking study that include inhibition of breast cancer protein (PDB ID: 4XO6) have been conducted for the first time. Inhibition studies of acetylcholinesterase, butyrylcholinesterase were performed to determine the inhibitory properties of the compound 4.

A dinuclear radical complex of tin(IV) based on differently charged o-iminoquinone ligands and 2-bipyridyl-tetrazine is prepared and characterized. It is shown that the tetrazine bridge in the [(^dippimSQ) Sn(^dippAP)]₂bptz complex is stabilized in the dianionic state, and this is confirmed by XRD. The diradical nature of the complex is determined by EPR and XRD data. Particular attention is paid to the analysis of redox states in the system containing two types of redox-active ligands in different oxidation states. The electronic absorption spectrum demonstrates a series of electronic transitions in the 700-1050 nm region due to the charge transfer between organic ligands. The obtained experimental data agree well with the results of density functional theory (DFT) quantum chemical calculations.

Crystals of new compound K(Al(H₂O)₆)₃[U₂(SO₄)₉] (1) are obtained and studied within the research of systems containing sulfates of U(IV) and lower charged cations. The synthesis is performed in the reducing medium (Al powder in the H₂SO₄ and iPrOH solution under UV radiation). Crystals of 1 are analyzed by single crystal X-ray diffraction and Raman spectroscopy. New ternary sulfate crystallizes in the trigonal crystal system with unit cell parameters: space group (Pbar{3}1c); a = 9.7988(3) Å, c = 24.4342(9) Å, V = 2031.8(1) Å³; Z = 2. The crystal structure of the new compound contains isolated charged [U₂(SO₄)₉]^10– anionic complexes linked by hydrogen bonds through octahedral aqua complexes [Al(H₂O)₆]³⁺ into a 3D framework with voids filled by potassium cations.

A new trans-bisalkynyl complex of Pt(II) is synthesized. It contains alkynyl ligands with the diphenylphosphoryl group and additional triphenylphosphine ligands. The composition and structure of the obtained complex are determined by high-resolution mass spectroscopy, polynuclear NMR and IR spectroscopy techniques. The molecular structure of the complex is determined by the single crystal X-ray diffraction analysis. The obtained complex is not found to demonstrate photoluminescence, which can be explained by the atypical composition and energy of electronic transitions described based on the quantum chemical computations.

The synthesis and crystal structure are described of new bimetallic platinum complex [Pt₂Cl₆(PPh₃)₂] (1) obtained by partial reduction of hexachloroplatinic acid H₂[PtCl₆] in the presence of triphenylphosphine and sodium hydrocarbonate in tetrahydrofuran. The complex is isolated as an intermediate reaction product. It is found that the crystal structure of complex 1 contains two platinum atoms in different coordination environments: Pt1 has the square planar geometry and Pt2 is a distorted tetragonal bipyramid. It is indicative of the presence of platinum in mixed oxidation states (II/IV). The molecules are packed mainly by C–H⋯Cl interactions in the crystal, as confirmed by the analysis of Hirshfeld surfaces and 2D fingerprints. The data obtained expand our knowledge about the intermediate products of H₂[PtCl₆] reduction and can be useful for understanding the mechanisms of homogeneous catalysis based on platinum complexes, particularly in hydrosilylation and silicone vulcanization reactions.

The structure of the isolated 5,6-diaminofurazano[3,4-b]pyrazine molecule is determined by quantum chemical computations and the single crystal X-ray diffraction analysis in the crystal with dimethylformamide (1:1). Structural parameters are obtained for the 5,6-diaminofurazano[3,4-b]pyrazine molecule in both phases. Differences are revealed in the geometries of the free molecule and the molecule in the crystal solvate with dimethylformamide, which are caused by noncovalent interactions of the phases, including intermolecular hydrogen bonds in the solid phase. Bader’s topological analysis of the electron density is performed for the model molecular cluster involving the dimer of 5,6-diaminofurazano[3,4-b]pyrazine with two dimethylformamide molecules.