[en] The structural and electrophysical characteristics of a number of solid solutions of layered perovskite-like oxides Bi_3–xY_xTiNbO₉ (x = 0, 0.1, 0.2, 0.3) have been studied. According to the data of powder X-ray diffraction, all the compounds are single-phase with the structures of two-layer Aurivillius phases (m = 2) with the orthorhombic crystal lattice (space group A2₁am). The temperature dependence of the relative permittivity ε/ε0(T) compounds have been measured and showed that the Curie temperature of the perovskite-like oxides Bi_3–xYxTiNbO₉ linearly increases with the substituting parameter x up to T_C = 965°C.

[en] 

Abstract—

Pt–Fe nanoparticles with a core–shell structure stabilized in polyethylene are studied via X-ray absorption spectroscopy. The temperature-dependent PtL_III-edge EXAFS (extended X-ray absorption fine structure) spectra of nanoparticle nuclei, consisting of platinum atoms, provide information on the interatomic-potential anharmonicity parameters along with the melting point T_melt and the Debye temperature, which are found to be 1630 and 208 K, respectively. This is much lower than for bulk platinum, where the values are 2041.4 and 233 K, respectively.

[en] The paper presents a theoretical DFT UB3LYP/6-311++G(d,p) modeling of the structure and magnetic properties of Cu(II) coordination compounds with tridentate Schiff bases derived from 2-tosylaminobenzaldehyde and amino alcohols. It is shown that the elongation of the aliphatic chain in the amine part of ligand systems prevents the formation of binuclear metal-chelate structures. At the same time, mononuclear bis-chelate complexes, as well as mono-adducts containing a coordinated solvent molecule and a tridentate azomethine compound, are formed regardless of the number of methylene units.

[en] Condensation of 7-hydroxy-4-methyl-8-formylcoumarin with 1,3-diaminopropan-2-ol has afforded a novel bis-azomethine, and its metal chelates with copper(II), nickel(II), and zinc(II) have been obtained. Structure and properties of the prepared compound have been studied by spectral and quantum-chemical methods.

[en] A new azomethine compound, 2-{(E)-[2-(4-hydroxybutylamino)benzimidazol-1-yl]iminomethyl}- phenol, and its cobalt(II) and copper(II) complexes were synthesized and characterized by IR, ¹Н NMR, and X-ray photoelectron spectroscopy and quantum-chemical calculations. The crystal and molecular structures of the cobalt complex were established by X-ray diffraction analysis. The oxidation state of the cobalt ion in the complex after its crystallization from the solution was defined more exactly by X-ray photoelectron spectroscopy.

[en] Novel complexes of Zn(II), Cd(II), Ni(II), and Co(II) with 3,5-di-tert-butyl-1,2-benzoquinone 3-hyd-roxynaphthoyl hydrazone have been synthesized. Composition, structure, magnetic and spectral properties of the obtained compounds have been studied by means of elemental analysis, IR, ¹H NMR, and UV spectroscopy, X-ray diffraction analysis, quantum-chemical simulations, and magnetochemistry.

[en] New Zn(II) and Cd(II) complexes with N-{2-[(E)-(4-tert-butylphenyl)iminomethyl]phenyl}-4-methylbenzenesulfonamide were synthesized by chemical and electrochemical methods. The ligand and metal complexes were characterized by the methods of IR, ¹H NMR, electron absorption spectroscopy, and X-ray absorption spectroscopy and by quantum chemical calculations. Electroluminescent devices with zinc and cadmium complexes were fabricated as emitter layers, which showed radiation brightness of 460 cd/m² (15 V) with a maximum at 502 nm and 140 cd/m² (15 V) with a maximum at 535 nm, respectively.

[en] Valence tautomer transition occurs mainly in 3d metalorganic complexes with redox-active ligands and makes them potential candidates for single-molecular switches. The transition occurs under temperature, pressure, or light-induced stimuli and is strongly affected by the intermolecular interactions. However single-crystal x-ray diffraction is not always applicable to such systems when crystal structure is destroyed upon transition or system is studied in the solution. Such an example is bis(o-semiquinonato) cobalt complex with TEMPO-functionalized iminopyridine ancillary ligand. In this work we apply two complementary techniques—ligand-sensitive Fourier transform infrared spectroscopy (FTIR) and metal sensitive Co K-edge x-ray absorption spectroscopy (XAS). In a solid state, a temperature hysteresis of magnetization larger than 40 K was observed upon cyclic cooling-heating. So, the temperature of phase transition upon cooling is about 40 K lower than that upon heating. In solution, the x-ray absorption spectra for high-temperature and low-temperature states were similar to that in the solid form, but the hysteresis was absent. Two methods are can probe valence tautomer transition, but XAS has an advantage for the liquid phase analysis and FTIR has larger sensitivity to the ligand related interactions in solid. (paper)