Synthesis of 1,2-bis(methoxyamino)cycloalkanes from alicyclic 1,2-bis(hydroxyamines)

Derivatives of 1,4-dihydroxypiperazine-2,3-dione were obtained by reaction of cis-1,2-bis(hydroxyamino)cycloalkanes with diethyl oxalate. Their alkylation with CH₂N₂ or Mel afforded 1,4-dimethoxypiperazine-2,3-diones. Hydrolysis of the latter gave 1,2-bis(methoxyamino)cycloalkanes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 925–929, April, 1996.     

Anomalous grazing incidence small-angle x-ray scattering studies of platinum nanoparticles formed by cluster deposition

The size evolution of platinum nanoparticles formed on a SiO2/Si(111) substrate as a function of the level of surface coverage with deposited clusters has been investigated. The anisotropic shapes of sub-nanometer-size nanoparticles are changed to isotropic on the amorphous substrate as their sizes increased. Using anomalous grazing incidence small-angle x-ray scattering (AGISAXS), the scattering from nanoparticles on the surface of a substrate is well separated from that of surface roughness and fluorescence. We show that AGISAXS is a very effective method to subtract the background and can provide unbiased information about particle sizes of less than 1 nm.     

Role of water structure in thermodynamics of nonpolar solvation

The SSOZ (site-site Ornstein-Zernike) equation with an original closure condition for liquid molecular systems is used to calculate thermodynamic functions of noble gas solvation in water. Water is modeled by two close sets of atom-atomic potential functions. The calculations indicate that the chemical solvation potential is strongly sensitive to water structure. A comparison with experiment is given. Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 4, pp. 736–741, July–August, 1996. Translated by L. Smolina     

Nanogel nanosecond photonic crystal optical switching

We developed a robust nanosecond photonic crystal switching material by using poly(N-isopropylacrylamide) (PNIPAM) nanogel colloidal particles that self-assemble into crystalline colloidal arrays (CCAs). The CCA was polymerized into a loose-knit hydrogel which permits the individual embedded nanogel PNIPAM particles to coherently and synchronously undergo their thermally induced volume phase transitions. A laser T-jump from 30 to 35 degrees C actuates the nanogel particle shrinkage; the resulting increased diffraction decreases light transmission within 900 ns. Additional transmission decreases occur with characteristic times of 19 and 130 ns. Individual NIPAM sphere volume switching occurs in the approximately 100 ns time regime. These nanogel nanosecond phenomena may be useful in the design of fast photonic crystal switches and optical limiting materials. Smaller nanogels will show even faster volume phase transitions.     

Investigations in the field of perinone compounds

The directed synthesis of structurally isomeric nitronaphthaloperinones — 10-nitro-and 11-nitro-14H-benz[4,5]isoquinolino[2,1-a]perinidin-14-ones — has been effected.For Communication I, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 6, pp. 842–843, June, 1970.     

Quantum-chemical analysis of the disproportionation of nitroxyl and peroxyl radicals in oxidizing organic compounds

The enthalpy change of disproportionation reaction of nitroxyl and peroxyl radicals was calculated by the DFT B3LYP/cc-pVDZ method. The regeneration of the corresponding hydroxylamine during the oxidation of unsaturated compounds inhibited by nitroxyl radicals is shown to be associated with the disproportionation of the nitroxyl and peroxyl radicals.     

Quantitative analysis of physical factors that determine the behavior of activity coefficients of electrolytes

The development of theoretical ideas on the cause and the mechanism of the change of activity coefficients is the main aim of the investigation. The model describing the interaction of hydrated ions in electrolytes is proposed. In the model the electrostatic forces between ions and change of the energy of the hydrate shell in the process of ion convergence determine ions distribution in solution. The significant factor is the dependence of dielectric permittivity on the concentration of the electrolyte and on the distance to ion. The statistical approach developed allows one to calculate the influence of principal physical factors and, on this basis, to explain the nature of curves describing the activity coefficients. The results of simulation have been tested on a large number of experimental data.     

Boron chelate complexes: X-ray and UV photoelectron spectra and electronic structure

Published data on the electronic structure of boron chelates are summarized for the first time. Ultraviolet photoelectron spectra of vapors, X-ray photoelectron spectra of molecular crystals, and results of modeling within the framework of the density functional theory are analyzed. Data on the effect of substituents on the electronic structure of complexes are systematized.     

Effect of Magneto-Pulse Processing on the Microstructure and Magnetic Behavior of Amorphous Electrotechnical Steel

The effect of magneto-pulse processing on the microstructure and magnetic behavior of amorphous electrotechnical steel is studied. It is found that the directed ordering of Fe atoms helps to increase specific magnetization of saturation and the coefficient of the squareness of the hysteresis loop, and is related to ordering of the spin system.