Reactivity of Ions of Actinides Towards Inorganic Free Radicals in Irradiated Aqueous Solutions

The paper is a short review of experimental data obtained during the study of reactivity of ions of actinides towards inorganic free radicals in irradiated aqueous solutions by pulse radiolysis method. The values of rate constants of reactions of these ions with primary products of water radiolysis (e_aq ^?, H, OH, O^?) and secondary radicals formed via reactions of these products with solutes and/or as a result of direct action of ionizing radiation on solutes (SO₄ ^?, NO₃, Cl₂ ^?, CO₃ ^?, O₂ ^? etc.) are listed. The peculiarities of the reactivity are discussed. The examples of application of the obtained data for the simulation of radiolytical transformations of ions of actinides are presented.     

Molecular dynamics simulation of dielectric constant and cluster structure of liquid methanol: the role of cluster–cluster dipole correlations

A molecular dynamics simulation of liquid methanol at ambient conditions with two different three-site potential models was performed and the evaluated dielectric constant was discussed in the light of the cluster structure of the liquid. The distribution of the pair interaction energy of molecules and the cluster size distribution were calculated. An aggregation contribution to dielectric constant was defined and calculated as a function of the threshold H-bond energy using energetic criterion of H-bond. The structural information on dipole–dipole correlations of molecules incorporated in the size and structure distribution of aggregates proved to cover about 80% of the calculated dielectric constant of methanol. The other 20% should be attributed to the cluster–cluster dipole correlations.     

Polarization interaction of disperse particles with not thin Debye atmosphere

The electric field of the equilibrium double layer acts only at the distance of the Debye length. Therefore, the distances at which the electrostatic interaction forces act between particles in the absence of external fields are limited by the same length. As shown previously, the external electric field results in the appearance of volume charges outside DL. As a result, the long-range acting electric forces appear. In addition, the forces become anisotropic.

The polarization forces are proportional to at least the square of the external field. Previously we had shown that quadratic forces occurred not only as a result of the interaction of the charges being linear to an external field, but as a result of the interaction between the charges being quadratic to an external field as well as the equilibrium charges. We have described these quadratic charges in the theory of the double layer nonlinear polarization without any restrictions on the double layer thickness. This theory was developed by the method of successive approximations on the extemal field and the electrokinetic ς-potential. These results are obtained in analytical form and agree with the Fixman and Jagannathan's 1983 numerical solutions.

Our calculations of the polarization interaction energy showed: (a) in suspension of polar nonconductive particles in the less polar medium the orientation of the duplet perpendicular to field is more advantageous than along the field; (b) the attraction of the charged polar particles is substituted by the repulsion with the particle ς-potential increase both for longitude duplet (ς=2.5 mV) and for transverse duplet (ς=1.5 mV); (c) with the polar medium conductivity growth the repulsion forces between particles of the longitude duplet are changed by the attraction forces.     

Geometric isomerism in the series of fluoroalkyl-containing 1,2,3-trione 2-arylhydrazones

According to the ¹H, ¹³C, and ¹⁹F NMR data, fluoroalkyl-containing 1,2,3-trione 2-arylhydrazones in CDCl₃ exist exclusively, while in (CD₃)₂CO preferentially, as isomers in which the acyl or aroyl group is involved in intramolecular hydrogen bond. The isomer structure was assigned on the basis of the chemical shifts of the carbonyl carbon atoms and fluorine atoms and carbon-fluorine spin-spin coupling constants J _C-F. X-Ray diffraction data showed that 1,2,3-trione 2-arylhydrazones in crystal have the same structure as in CDCl₃ solution. Quantum-chemical calculations were performed to rationalize predominant formation of 1,2,3-trione 2-arylhydrazone isomers with a free polyfluoroacyl group.     

Nonlinear luminescence of high-concentration rhodamine solutions: On the problem of pulsed laser cooling

The conditions of occurrence of collective photoinduced luminescence in model solutions are determined. The transmittance and luminescence of concentrated solutions of rhodamine 101 under excitation by laser pulses in the Stokes and anti-Stokes spectral ranges are studied. It is shown that, at high pump energies, collective photoinduced luminescence, which competes with induced radiation, plays a significant role in luminescence generation. Temperatures of heating and cooling of solutions are estimated. The photodynamics of cooling of solutions of complex molecules under their pulsed (Stokes and anti-Stokes) excitation is analyzed.     

Synthesis and structure of 5,7-diisopropyl-2-(quinolin-2-yl)-1,3-tropolone derivatives

Russian Chemical Bulletin - A synthetic procedure towards 4,6-diisopropyl-3-nitro-1,2-benzoquinone was elaborated. Based on this benzoquinone, a series of novel...     

6,6'-[piperazine-1,4-diylbis(methylene)]bis[3,5-di(<Emphasis Type="Italic">tert</Emphasis>-butyl)-1,2- benzoquinone]: Synthesis and properties

Preparation method is developed for a new 6,6'-[piperazine-1,4-diylbis(methylene)]bis[3,5-di(tert-butyl)- 1,2-benzoquinone], including the stage of 3,5-di(tert-butyl)pyrocatechol aminoalkylation by Mannich reaction followed by oxidation. The molecular structure of one of its hydrolysis products, 4,6-di(tert-butyl)-2,3-dihydroxybenzaldehyde, is established by X-ray diffraction (XRD) analysis.