Demethylation of the SMe2 substituent in metallacarboranes. Synthesis and structures of the complexes Cp*M(η-9-SMe-7,8-C2B9H10) (M = Rh, Ir)

The demethylation of the cations [Cp*M(??-9-SMe₂-7,8-C₂B₉H₁₀)]⁺ (1a,b) with PhCH₂SNa affords neutral metallacarboranes Cp*M(??-9-SMe-7,8-C₂B₉H₁₀) (2a: M = Rh; 2b: M = Ir). The reverse reaction can be performed by the treatment of complexes 2a,b with MeI in the presence of TlPF₆. The structures of complexes 2a,b were determined by X-ray diffraction.     

Cationic hexamethylbenzene-diene cobalt complexes

Cationic complexes [(diene)Co(??-C₆Me₆)]⁺ (diene is buta-1,3-diene (2a), 5-isopropyl-2-methylcyclohexa-1,3-diene (2b), cycloocta-1,3-diene (2c), and cyclohexa-1,5-diene (2d)) were synthesized by the reaction of [Co(??-C₆Me₆)₂]⁺ (1) with dienes in a CH₂Cl₂-Me₂CO mixture. In the absence of dienes, cation 1 undergoes hydrogenation to form [(1,2,3,4,5,6-HMCD-1,3)-Co(??-C₆Me₆)]⁺ (HMCD is hexamethylcyclohexadiene, 2e). Structures [2c?Ce]PF₆ were determined by X-ray diffraction analysis. According to the DFT calculations, the Co-C₆H₆ bond in the complexes with conjugated dienes is stronger than that in the complexes with nonconjugated dienes.     

Excitation transfer in the plasma of a barrier discharge in a krypton-xenon mixture

Processes of excitation transfer in the plasma of a barrier discharge in a krypton-xenon mixture are studied. A kinetic diagram of energy transfer is proposed, and a system of coupled kinetic equations describing the dynamics of processes in the plasma of a barrier discharge of mixtures in pure xenon as well as in a krypton-xenon mixture is composed and solved. The effect of excitation transfer on the population distribution over vibrational levels of krypton excimers excited by a barrier discharge in a krypton-xenon mixture is studied. The deviation from the equilibrium distribution over vibrational levels is found. It can be interpreted as an indication of the activation of the mechanism of depopulation of the lowest vibrational levels of excimer states of krypton.     

Pseudoperturbation method for computation of E. Schmidt eigenvalues

In two problems with approximately given n -multiple generalized E. Schmidt eigenvalue with relevant Jordan chains pseudoperturbation method is applied for their sharpening. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

On conditions of flutter onset for elongated plate in supersonic gas flow

The scheme developed in [1] of the investigation of Poincaré–Andronov-Hopf bifurcation on the base of the Lyapounov-Schmidt method is applied to two boundary value problems for nonlinear ordinary differential equation describing the oscillations of an elongated plate in supersonic gas flow. Necessary conditions for the existence of periodic solutions are obtained. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Subgroup structure of bifurcation equations with crystallographic group symmetry

For stationary and Andronov-Hopf bifurcation with symmetry of highest crystalline classes of basic syngonies of symmorphic crystallographic groups as semidirect products of translations on basic directions and point symmetry of lattice the subgroup structure of relevant bifurcation equations and bifurcating solutions dual to subgroup structure of such symmetry is investigated. Applications to phase transitions in physics are considered. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Production of Intense Ion Beams of Nickel,Chromium, Silicon,and Cobalt at the DC-60 Cyclotron

Physics of Particles and Nuclei Letters - This article describes experiments for producing highly intense metal ion beams at the ECR source of the DC-60 cyclotron using the evaporation of...     

Properties of strontium titanate in the SrTiO3/CeO2/Al2O3 multilayered structure

Studies of the crystal structure, elemental composition, and dielectric properties of strontium titanate films in SrTiO₃/CeO₂/Al₂O₃ multilayered structures are reported. Data on the crystal lattice and impurity contents have been obtained, and temperature and electric field dependences of the dielectric properties of SrTiO₃ films in the microwave range have been measured. An analysis of the results is made to establish the reason for the nonmonotonic dependence of the small-signal dielectric permittivity of SrTiO₃ films on temperature. Fiz. Tverd. Tela (St. Petersburg) 39, 1024–1029 (June 1997)