Journal of Structural Chemistry最新文献

We present the results of studying HfO_x films formed from tetrakis(dimethylamino)hafnium with different times of water supply pulses. The stoichiometry of the samples obtained is estimated by spectral ellipsometry and Auger electron spectroscopy. It is shown that an increase in the water supply duration promotes an increase in the x value in the HfO_x layer. When the time of water supply pulses varies from 10 ms to 1000 ms, x values ranging from 1.76 to 1.84 are obtained. A method based on the refractive index is proposed to estimate the stoichiometry of HfO_x layers.

Samarium hydrogen iodate Sm(IO₃)₃·HIO₃ was successfully synthesized by the unconventional low-temperature solution-melt method, its structure was determined by X-ray diffraction analysis of single crystals. This compound crystallizes in the monoclinic space group P2₁/c with lattice parameters: a = 10.4637(6) Å, b = 7.4629(5) Å, c = 14.0174(13) Å, β = 110.53(0), Z = 6. In the studied structure, samarium atoms are surrounded by 8 oxygen atoms in a polyhedron in the form of a distorted square antiprism. The iodate groups are linked through common oxygen atoms of the SmO₈ antiprism into a three-dimensional framework. The compound was characterized by X-ray diffraction, IR and NQR spectroscopy and EDX analysis.

An aroylhydrazone compound N’-(5-chloro-2-hydroxybenzylidene)-3-methylbenzohydrazide (H₂L) has been synthesized and characterized by elemental analysis, infrared and electronic spectra, and ¹H NMR spectrum. With the aroylhydrazone and maltol (HL^a) or ethyl maltol (HL^b) as ligands, two oxidovanadium(V) complexes, [VOLL^a] (1) and [VOLL^b] (2), have been synthesized and characterized by elemental analysis, infrared and electronic spectra, and ¹H NMR spectra. Structures of the complexes were further confirmed by single crystal X-ray determination. The V atoms in the complexes are coordinated by the ONO donor atoms of the aroylhydrazone ligand L, OO donor atoms of maltolate (L^a) or ethyl maltolate (L^b) ligand, and one oxido O atom, forming octahedral coordination. The complexes function as effective olefin epoxidation catalysts with hydrogen peroxide as terminal oxidant and sodium hydrogen carbonate as a co-catalyst.

7-Bromo-5-(tert-butyl)-2-phenyl-1H-indene (1) and 6,7-dibromo-2,4-dimethyl-2,3-dihydro-1H-inden-1-one (2) are analyzed by single crystal X-ray diffraction. The conformational structure, vibrational spectrum of molecules, topology and hierarchical complexity of crystal structures are discussed. The structure of 1 is layered and contains (100) molecular layers of the tts topological type. The structure of 2 does not contain long molecular ensembles but demonstrates short Br⋯O contacts linking molecules into a centrosymmetric dimer.

The first aqueous silver borate nitrate Ag₃B₄O₆(OH)₂(NO₃) has a non-centrosymmetric crystal structure (P4₃2₁2, a = 10.0196(3) Å, c = 9.2594(2) Å). The compound is prepared by soft hydrothermal synthesis inside an evacuated quartz ampoule. The structure of the resulting 1D–5B-borate compound is formed by [B₄O₆(OH)₂]^2– chains consisting of two triborate rings with a common (2Δ3□:(‹Δ2□›–‹Δ2□›–)^∞ tetrahedron and NO₃ triangles with silver atoms between the rings. The relationship between the structures of Ag₃B₄O₆(OH)₂(NO₃), Tl₂B₄O₆(OH)₂·2H₂O and the kernite Na₂B₄O₆(OH)₂·3H₂O (also formed by [B₄O₆ (OH)₂]^2– chains) is discussed.

The study of manganese-substituted barium hexaferrite BaFe_12–xMn_xO₁₉ with a degree of substitution x from 0 to 2 is presented. The samples are prepared by the solid-phase synthesis at a temperature of 1275 °C and isothermal holding for 5 h. The elemental composition of the samples is determined using energy dispersive spectroscopy, which shows good correspondence with the specified calculated compositions. Monophasicity of all synthesized samples is confirmed by powder X-ray diffraction. In addition, the effect of manganese substitution on the unit cell parameters is estimated. In the differential scanning calorimetry study of the properties, the effect of manganese substitution for iron on the Curie points of the samples obtained, which are caused by changes in the magnetic structures of the produced materials, is determined. The results indicate a significant effect of manganese substitution on the properties of barium hexaferrite and confirm the possibility to control the substitution process for the production of materials with adjustable magnetic characteristics.

Reduction of Ar^BIG-bian (Ar^BIG-bian = 1,2-bis[(2,6-dibenzhydryl-4-methylphenyl)imino]acenaphthene) by an excess of metal aluminum in the presence of AlCl₃, AlBr₃ or AlI₃ in toluene leads to the formation of dihalide anion-radical complexes [(Ar^BIG-bian)^–AlX₂] (X = Cl (1), Br (2), I (3)). The newly obtained compounds 1, 2, 3 are isolated in the crystal state and characterized by IR and EPR spectroscopies and by elemental analysis. Molecular structures of the complexes are determined by XRD.

Information on the synthesis and structure of lanthanide coordination compounds with ligands containing a benzothiazolate fragment in their structure is summarized up to the beginning of 2024. Particular attention is paid to the photo- and electroluminescent properties of these compounds.

A new coordination compound of Co(II) [Co(pydc)₂](pydcH₂)(Hapy)(H₂O)₅ (1) (where, pydcH₂ = pyridine-2,6-dicarboxylic acid; Hapy = protonated 2- aminopyridine) was synthesized and characterized by single crystal X-ray diffraction (SC-XRD) analyses. Crystallographic analysis (CIF file CCDC no. 2236169) revealed that complex 1 has distorted octahedral geometry with pydc coordinated as a tridentate ligand to a metal ion. The electronic structure of the complex was determined using DFT calculations with pseudo potential of LANL2DZ basis function for Cobalt atom while B3LYP/GEN level using 6-31+G* basis set for other atoms. The optimized structure can reproduce the crystal structure with good accuracy at this computational level. Frontier molecular orbital analysis and molecular electrostatic potential (MEP) have been evaluated to understand the reactivity characteristics of the complex. Natural bond orbital analysis illustrates the charge transfer between the donor and acceptor sites of the investigated complex. Further, the intermolecular contacts of the complex areanalyzed through Hirshfeld surface analysis and finger print plots.

A dichlorophenyl substituted nitronyl nitroxide radical 2-(2,6-dichlorophenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (L) is prepared, its structure and magnetic properties are studied. It is shown that the interaction of bis(hexafluoroacetylacetonato)copper(II) [Cu(hfac)₂] with L leads to the formation of the {[Cu(hfac)₂][Cu(hfac)₂L₂]} heterospin complex whose crystal structure consists of pseudo-polymer chains formed by alternating single-spin [Cu(hfac)₂] and three-spin [Cu(hfac)₂L₂] fragments. It is established that the temperature dependence of magnetic susceptibility of {[Cu(hfac)₂][Cu(hfac)₂L₂]} is determined by ferromagnetic exchange interactions between unpaired electrons of Cu(II) ions and the axially coordinated L in three-spin fragments.