E. V. Korotaev

EFFECTS OF THE NEAREST-NEIGHBOR ENVIRONMENT OF COPPER ATOMS ON THE XANES SPECTRA OF LAYERED CHROMIUM-COPPER DISULFIDES

In the present work, the K absorption spectra of copper, chromium, and vanadium of layered chromiumcopper disulfides CuCr1–xVxS2 (x = 0–0.4) are studied. Based on the comparison of the experimental and theoretical spectra obtained by simulation with the FDMNES program package, it is shown that copper atoms occupy tetrahedral sites, and chromium atoms and substitutional vanadium atoms occupy octahedral sites in the whole set of the samples studied.

XES investigation of the layered vanadium-substituted copper-chromium disulfides

XRD data on the layered vanadium-substituted copper-chromium disulfides (CuCr1−xVxS2, x = 0−0.4) are compared with the data obtained by X-ray emission and photoelectron spectroscopies.

Electronic structure of calix[4]arene thioethers and their complexes with palladium, as studied by X-ray emission spectroscopy, X-ray photoelectron spectroscopy, and quantum chemistry

The charge state of calix[4]arene thioethers and their complexes with palladium was studied by X-ray emission spectroscopy and X-ray photoelectron spectroscopy. Experimental data were compared with the results of quantumchemical calculations. The involvement of the sulfur lone electron pairs in the coordination to Pd atoms causes a decrease in the energies of the corresponding MOs having contributions from the sulfur 3p AOs and, consequently, a decrease in the intensity of the maximum A on going from the S(Kβ) spectra of free ligands to the spectra of complexes. The binuclear nature of the complexes does not lead to the onset of significant additional interactions between two metal centers.

XANES investigation of manganese sulfide solid solutions

A comprehensive study of the valence state and the local coordination character of Mn1-xYbxS (x = 0; 0.01; 0.05) solid solutions has been performed using X-ray absorption spectroscopy combined with finite difference method calculations. The good agreement between experimental and calculated data indicates that cationic substitution does not lead to significant changes in the manganese local coordination character. The ytterbium atoms are found to be in the trivalent state, while the manganese and sulfur atoms are in the divalent state.

Xanes of X-ray absorbtion K edges of chromium dichalcogenides CuCr1-xM′xS2 and MCrX2

In the work X-ray K edges of chromium dichalcogenides CuCr1-xMx′S2 (M = V, Fe; x = 0-0.40) and MCrX2 (M = Cu, Ag, Na; X = O, S, Se) were studied experimentally and theoretically. Comparison of fine structures of experimental XANES spectra obtained using a synchrotron radiation source and theoretical absorption spectra modelled using FDMNES software package allows one to study the influence of types of intercalate M, chalcogene X and also the effect of the cation substitution of chromium atoms by vanadium and iron on XANES structure of K edges in CuCr1-xMx′S2 and MCrX2.

Structure and spin crossover in an iron(II) compound with tris(pyrazol-1-yl)methane and the complex Eu(dipic)2(Hdipic)]2– anion

An iron(II) complex with tris(pyrazol-1-yl)methane (HC(Pz)3) of the composition [Fe(HC(Pz)3))2]·[Eu(dipic)2(Hdipic)]·2H2O, containing an outer-sphere complex anion, is synthesized. The compound is examined by single crystal and powder X-ray diffraction, UV-Vis and IR spectroscopies, and static magnetic susceptibility. The investigation of the temperature dependence χ(T) in the temperature range 80-470 K reveals that the polycrystalline phase of the compound undergoes spin-crossover 1А1 ⇔ 5Т2. The transition is accompanied by thermochromism (color change pink ⇔ white).

Spin-crossover in coordination compounds of iron(II) with tris(pyrazol-1-yl)methane and cluster anions

Synthesis procedures for new coordination compounds of iron(II) with tris(pyrazol-1-yl)methane (HC(pz)3), containing cluster anions in the outer sphere, of the composition [Fe{HC(pz)3}2][Mo6Cl14]•2H2O (I), [Fe{HC(pz)3}2][Mo6Br14]•H2O (II), and [Fe{HC(pz)3}2]2[Re6S8(CN)6]•2H2O (III) are developed. The compounds are studied by static magnetic susceptibility, electronic, IR, and Mössbauer spectroscopic methods. The magnetochemical study shows that in the polycrystalline phases of all compounds the spincrossover 1А1 ⇔ 5Т2 is observed which is accompanied by thermochromism.

X-ray and Auger microprobe studies of vanadium-doped layered chromium-copper disulfide crystals

In the work, X-ray and Auger microprobe studies of the surface of crystals prepared from powder samples of CuCr1−xVxS2 disulfides (x = 0÷0.11) by crystallization from melt in the sulfur vapor atmosphere. Sample slabs cut from ingots include crystalline layered blocks with different orientation of copper-containing extended linear inclusions separated by disulfide matrix layers. The results of the microprobe analysis of regions with copper-containing inclusions and the regions adjacent to them are presented.

Photoelectron spectra of powder and single crystalline chromium-copper disulfides

Abstract2p3/2,1/2 Photoelectron spectra of single crystalline specimens of chromium-copper disulfides CuCrS2 and CuCr0.85V0.15S2 are studied. It is shown that the spectra of single crystalline specimens substantially differ from the corresponding spectra of chromium-copper disulfides in the powder state.