Synthesis and Structure of Tetraphenylantimony Methacrylate and Tetraphenylantimony Crotonate and Their Use for the Production of Antimony-Containing Polystyrene

Russian Journal of General Chemistry - Tetraphenylantimony methacrylate Ph4SbO2CC(CH3)=CH2 and tetraphenylantimony crotonate Ph4SbO2CCH=CHCH3 were synthesized by the action of acids on Ph5Sb or on...     

The Crystal-Chemical Features of Phases and the Nature of the Coordination Bond in the System [CuxNi(1 – x){N(CH2PO3)3}]Na4 · nH2O (x = 0–1)

Crystallography Reports - The structural features of the phases formed during crystallization of mixed copper and nickel complexes with nitrilotris(methylenephosphonic acid)...     

Heat-transfer mechanisms in solar flares. 2: Consideration of heat-flux relaxation

The physical properties of the process of heat transfer from a solar-flare’s energy source (a high-temperature reconnecting current layer) to the surrounding plasma of the Sun’s atmosphere are investigated. Major attention is given to consideration of the collisional relaxation of the heat flux and to analysis of its related effects. The physical meaning of this phenomenon is that the heat flux responds to a change in the spatial temperature distribution with a delay rather than immediately, as in the simplest approximation described by the classical Fourier’s law. It is shown that this mechanism describes the heat transfer in flares better than classical and anomalous heat conduction (see Part 1).     

Magnesium phosphate clamps for spent nuclear fuel

Magnesium phosphate clapms are offered for conditioning spent nuclear fuel (SNF). It is experimentally shown that the starting material has a high fluidity which persists for not less one hour. It will allow reliable pouring tight SNF. The solid material with a density of 1.5–1.8 g cm⁻³ can function as a protective barrier: It is insoluble in water, and strontium and cesium radionuclides are strongly fixed in the material structure.     

New binuclear <Emphasis Type="Italic">bis</Emphasis>(2,4,6,8-tetramethyl-2,4,6,8-tetraazobicyclo(3.3.0)octane-3,7-dione-<Emphasis Type="Italic">O,O</Emphasis>')-tetraaqua-hexakis(nitrato-<Emphasis Type="Italic">O,O</Emphasis>')-disamarium(III) complex: Synthesis and crystal structure

The centrosymmetric binuclear complex of samarium(III) nitrate with bicyclic biscarbamide 2,4,6,8-tetramethyl-2,4,6,8-tetraazabicyclo(3.3.0)octane-3,7-dione, or mebicar (Mk) namely, [Sm(C₈H₁₄N₄O₂)(H₂O)₂(NO₃)₃]₂ (I) has been synthesized. Its crystal structure has been characterized (CIF file CCDC no. 1451436). Crystals of complex I are triclinic, space group P1 a = 9.8661(2) Å, b = 10.2913(3) Å, c = 10.9629(3) Å, α = 74.475(2)°, β = 67.802(2)°, γ = 67.570(2)°, V = 942.68(5) ų, ρcalcd = 2.01028 g/cm³, and Z = 1. The samarium atom is coordinated by the two oxygen atoms of two Mk molecules bonded via the symmetry center, three bidentate nitrate anions, and two water molecules. The coordination number of the samarium atom is 10, the coordination polyhedron of the metal atom is a decahedron and the Sm…Sm distance is 9.7904(4) Å.     

Synthesis and structure of catena((μ2-4,4,10,10-tetramethyl-1,3,7,9-tetraazaspiro[5.5]undecane-2,8-dione-O,O′)dichloro-zinc)

Russian Journal of Coordination Chemistry - The coordination polymer, catena-((μ2-4,4,10,10-tetramethyl-1,3,7,9-tetraazaspiro[5.5]undecane-2,8-dione-O,O′)dichloro-zinc)...     

Synthesis and structure of the platinum complexes [Bu4N]+[PtBr5(DMSO)]?, [Ph4P]+[PtBr5(DMSO)]?, and [Ph3(n-Am)P]+[PtBr5(DMSO)]?

The complexes [Bu₄N]₂⁺[PtBr₆]²⁻ (I), [Ph₄P]₂⁺[PtBr₆]²⁻ (II), and [Ph₃(n-Am)P]₂⁺ (III) are synthesized by the reactions of tetrabutylammonium bromide, tetraphenylphosphonium bromide, and triphenyl(n-amyl)-tetraphenylphosphonium bromide, respectively, with potassium hexabromoplatinate (mole ratio 2: 1). After recrystallization from dimethyl sulfoxide, complexes I, II, and III transform into [Bu₄N]⁺[PtBr₅(DMSO)]⁻ (IV), [Ph₄P]⁺[PtBr₅(DMSO)]⁻ (V), and [Ph₃(n-Am)P]⁺[PtBr₅(DMSO)]⁻ (VI). According to the X-ray diffraction data, the cations of complexes IV–VI have a slightly distorted tetrahedral structure. The N-C and P-C bond lengths are 1.492(7)–1.533(6) and 1.782(10)–1.805(10) ?, respectively. The platinum atoms in the mononuclear anions are hexacoordinated. The dimethyl sulfoxide ligands are coordinated with the Pt atom through the sulfur atom (Pt-S 2.3280(18)–2.3389(11) ?). The Pt-Br bond lengths are 2.4330(6)–2.4724(6) ?.     

Plasma heating by discontinuous MHD flows in the vicinity of a magnetic reconnection region

An expression that explicitly describes variations in the internal energy of the plasma that flows through a discontinuity is derived based on the complete system of boundary conditions for the MHD equations on the discontinuity surface. The dependence of the plasma heating on the magnetic field density and configuration in the vicinity of the discontinuity surface (i.e., on the MHD flow type) is studied. The conditions of plasma heating at discontinuities in a self-consistent analytical model of magnetic reconnection are discussed.     

The fibre track detector

The new type of a solid state track detector is described. The detector consists of the fibre or capillary target and the multistage image intensifier. The standard microchannel plate filled with liquid scintillator and the input fibre plate of the image intensifier was investigated as the targets.     

Dynamics of complex-shape traveling pulses in a fitz hugh-nagumo system with modulated parameters

The dynamics of traveling-pulse solutions is studied for a Fitz Hugh-Nagumo model with modulated parameters. The boundaries of the modulation depth of the system parameters where these solutions still exist are found by numerical simulation. The compensation effect of the parameter modulation acting on the stability of such solutions is obtained. This work was presented at the Summer Workshop “Dynamic Days” (Nizhny Novgorod, June 30–July 2, (998). Lobachevsky State University of Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 12, pp. 1586–1592, December, 1998.