Electron beam stimulated chemical reaction in solids

Use of electron beams allows to obtain new effects in high temperature chemistry of solid state. A stimulated influence of irradiation at comparable temperature conditions may be a subject of technological interest taking into account that increase of reaction rate can reach significant values.     

Effect of the electronic structure of the radical anions of 4-substituted 1,2-and 1,3-dinitrobenzenes on the regioselectivity of reduction of the nitro groups

Theoretical and experimental regularities of the regioselectivity of the reduction of one of the two nitro groups in unsymmetrical dinitrobenzenes were studied. It was found that the regioselectivity of the formation of isomeric nitroanilines depends on the structure of the substrate and the nature of the reducing agent. The reduction regioselectivity model was verified, according to which radical anion protonation is the major reaction direction.     

Electrochemical dimerization of 9-acetylanthracene

Conclusions It was shown that the main product of the one-electron electrochemical reduction of 9-acetylanthracene in an aprotic solvent is a tail-tail-type 9,9-diacetyl-9,9,10,10-tetrahydrobianthryl dimer.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2812–2814, December, 1987.     

Spatial spin-modulated structure and hyperfine interactions of 57Fe nuclei in multiferroics BiFe1–x T x O3 (T = Sc,Mn; x = 0, 0.05)

The results of the Mössbauer studies on ⁵⁷Fe nuclei in multiferroics BiFe_1–x T _x O₃ (T = Sc, Mn; x = 0, 0.05) in the temperature range of 5.2–300 K have been presented. The Mössbauer spectra have been analyzed in terms of the model of an incommensurate spatial spin-modulated structure of cycloid type. Information has been obtained about the effect of the substitution of Sc and Mn atoms for Fe atoms on the hyperfine parameters of the spectrum: the shift and the quadrupole shift of the Mössbauer line, the isotropic and anisotropic contributions to the hyperfine magnetic field, and also the parameter of anharmonicity of the spatial spin-modulated structure.     

Divinyl selenide: conformational study and stereochemical behavior of its 77Se-1H spin-spin coupling constants

Theoretical energy-based conformational analysis of divinyl selenide performed at the MP2/6-311G** level is substantiated by the second-order polarization propagator approach (SOPPA) calculations and experimental measurements of its (77)Se-(1)H spin-spin coupling constants, demonstrating marked stereochemical behavior in respect of the internal rotation of both vinyl groups around the Se-C bonds. Based on these data, divinyl selenide is shown to exist in an equilibrium mixture of three nonplanar conformers: one the preferred syn-s-cis-s-trans and two minor anti-s-trans-s-trans and syn-s-trans-s-trans forms.     

Synthesis and Study of Tetraamminenickel 9-Molybdomanganate [Ni(NH3)4] · H4[MnMo9O32] · 6H2O

Tetraamminenickel 9-molybdomanganate [Ni(NH₃)₄] · H₄[MnMo₉O₃₂] · 6H₂O (zbdI) has been synthesized and studied by thermogravimetry, IR spectroscopy, and X-ray powder diffraction analysis. The crystals of compound I are monoclinic: a = 11.5961 Å, b = 11.1609 Å, c = 8.7200 Å, β = 109.23°, V = 1065.59 ų, ρ_calcd = 3.067 g/cm³, Z = 1.     

Station for X-ray structural analysis of materials and single crystals (including nanocrystals) on a synchrotron radiation beam from the wiggler at the Siberia-2 storage ring

The design of the station for structural analysis of polycrystalline materials and single crystals (including nanoobjects and macromolecular crystals) on a synchrotron radiation beam from the superconducting wiggler of the Siberia-2 storage ring is described. The wiggler is constructed at the Budker Institute of Nuclear Physics of the Siberian Division of the Russian Academy of Sciences. The X-ray optical scheme of the station involves a (1, ?1) double-crystal monochromator with a fixed position of the monochromatic beam and a sagittal bending of the second crystal, segmented mirrors bent by piezoelectric motors, and a (2θ, ω, φ) three-circle goniometer with a fixed tilt angle. Almost all devices of the station are designed and fabricated at the Shubnikov Institute of Crystallography of the Russian Academy of Sciences. The Bruker APEX11 two-dimensional CCD detector will serve as a detector in the station.     

4-Dimethylaminoacetophenone O-vinyloxime: Synthesis and steric structure

4-Dimethylaminoacetophenone oxime was synthesized from 4-dimethylaminoacetophenone and hydroxylamine hydrochloride. Its reaction with acetylene in the system KOH-DMSO gave previously unknown 4-dimethylaminoacetophenone O-vinyloxime as the major product. According to the experimental data and quantum-chemical calculations, 4-dimethylaminoacetophenone O-vinyloxime is formed as the only E isomer with preferential s-trans conformation of the vinyloxy group, which is characterized by essentially nonplanar structure.     

An asymptotic theory of the sound dispersion in a binary mixture of gases

The sound propagation in a binary mixture of multiatomic non-relaxing gases is considered using Burnett's equations (for the case of rapid exchanges of the internal and translational energies of the molecules). Asymptotic expressions (for small Knudsen numbers) are obtained for the absorption and dispersion coefficients, which are expressed in terms of the Navier–Stokes and the Navier–Stokes and the Burnett transport coefficients respectively. “Working” expressions of different levels of accuracy for these coefficients are known for the case of a binary mixture of monatomic gases. For this case, the results obtained are compared with known ones and the drawbacks and errors of previous papers are pointed out.