Influence of the Structure of the Organic Moiety of Copper(II) Porphyrins on Their Reactivity toward Acids

The acid-induced dissociation of copper(II) porphyrin complexes with a high degree of meso- and β-substitution in the ligand was studied. The copper(II) complexes with octaethylporphyrins containing 0, 1, 2, 3, and 4 meso-phenyl substituents were ranked with respect to the stability. Octaβ-alkyl and unsymmetrical meso-phenyl substitution affects not only the quantitative characteristics of dissociation of the complexes but also the kinetic relationships of the process.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 3, 2005, pp. 497–503.Original Russian Text Copyright © 2005 by Kosareva, Klyueva, Lomova, Suslova.     

Self-transformation of a powerful femtosecond laser pulse into a white-light laser pulse in bulk optical media (or supercontinuum generation)

We present experimental and theoretical results on white-light generation in the filamentation of a high-power femtosecond laser pulse in water and atmospheric air. We have shown that the high spatio-temporal localization of the light field in the filament, which enables the supercontinuum generation, is sustained due to the dynamic transformation of the light field on the whole transverse scale of the beam, including its edges. We found that the sources of the supercontinuum blue wing are in the rings, surrounding the filament, as well as at the back of the pulse, where shock-wave formation enhanced by self-steepening takes place. We report on the first observation and demonstration of the interference of the supercontinuum spectral components arising in the course of multiple filamentation in a terawatt laser pulse. We demonstrate that the conversion efficiency of an initially narrow laser pulse spectrum into the supercontinuum depends on the length of the filament with high intensity gradients and can be increased by introducing an initial chirp. PACS 42.65.Jx; 42.65.Re; 42.25.Bs; 42.50.Hz     

Formation of a paramagnetic complex from the bischelate of palladium(II) with dehydrogenated N-(3-hydroximino-2-methylbutyl-2)hydroxylamine and o-phenanthroline

The reaction in absolute ethanol of -phenanthroline and the diamagnetic bischelate of palladium(II) containing anions of dehydrogenated N-(3-hydroximino-2-methylbutyl-2)hydroxylamine yields a paramagnetic palladium(II) complex which contains a coordinated anion-radical of dehydrogenated 1,2-hydroxylaminooxime.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 1959–1961, September, 1991.     

Porphyrin models of natural catalases

The kinetics of H₂O₂ decomposition in the presence of copper complexes with porphyrins, whose structure is regularly changed, was studied by the volumetric method. The ion-molecular mechanism of the reaction was proposed on the basis of spectrophotometric analysis of the intermediates. The use of these complexes as simple models of natural catalases was shown to be promising. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 719–724, April, 2007.     

Molecular structure of a zwitter-ionic 2-piperidinyl-4-dinitromethyl-1,3,5-triazin×(1H, 5H)-6-one salt

A zwitter-ionic salt 2-piperidinyl-4-dinitromethyl-1,3,5-triazin(1H,5H)-6-one is studied by the single crystal X-ray analysis. The crystals are monoclinic: a = 11.526(1) Å, b = 9.211(1) Å, c = 12.182(1) Å; β = 110.69(1)°, V = 1209.9(2) ų, space group P2₁/n; Z = 4, ρ_calc = 1.560 g/cm³. The transformation of the dinitromethyl fragment conformation, the conjugation of one of nitrogroups with the 1,3,5-triazine ring, and an intramolecular hydrogen bond are revealed. The 1,3,5-triazine cycle is strongly distorted due to lactam-lactim tautomerism.     

Synthesis of Methyl 5(6)-(4-Aminophenoxy)- and 5(6)-(2-Aminophenoxy)-2-benzimidazolyl Carbamates and Their Biological Properties

A procedure was developed for preparation of methyl 5(6)-(4-aminophenoxy)- and 5(6)-(2-aminophenoxy)-2-benzimidazolyl carbamates by reaction of 3,4,4`-triaminodiphenyl or 3,4,2`-triaminodiphenyl ethers respectively with methyl cyanocarbamate in water solution in the presence of 7-10 molar excess of acetic acid. The helminthicidal properties, embryotoxicity, and overall toxicity of compounds obtained were estimated.     

Moving focus in the propagation of ultrashort laser pulses in air

The long light filaments generated in air by powerful ultrashort laser pulses, previously attributed to self-channeling, were investigated by use of gigawatt pulses from a Ti:sapphire chirped-pulse-amplification laser system. A filament contained only a small fraction of the pulse energy and always ended at the diffraction length of the beam (~100 m), independently of the pulse energy. These features are explained by the moving-focus model, which is presented as an alternative to the self-channeling model. Computer simulations involving ionization of the air also support the moving-focus model.     

Filamentation of femtosecond laser pulses in turbulent air

Formation and wandering of filaments in air are studied both experimentally and numerically. Filament-center deflections are collected from 1100 shots of 190-fs and 800-nm pulses in the plane perpendicular to the propagation direction. To calculate the filament wandering in air we have developed a model of powerful femtosecond laser pulse filamentation in the Kolmogorov atmospheric turbulence and employed the Monte Carlo method to model the propagation of several hundred laser pulses. Statistical processing of experimental and numerical data shows that filament-center displacements in the transverse plane obey the Rayleigh-distribution law. Parameters of the Rayleigh distribution obtained for numerical and experimental data are close to each other. Received: 23 May 2001 / Revised version: 26 September 2001 / Published online: 29 November 2001     

Nitrogen bases in the coking products of coal (composition,methods of isolation,and utilization) (Review)

The compositions and yields of nitrogen bases during thermochemical transformations of the organic mass of coals are presented. The dependence of the distribution of nitrogen in the products of thermal refining of coal on the type of field, the degree of metamorphism, and the coking temperature is demonstrated. The percentages of nitrogen bases in the coking products, the composition of the base fractions, and a list of reagents of the pyridine and quinoline series developed in the USSR are presented. The industrial methods for the isolation of the nitrogen bases from coking gas and coal tar in the USSR and abroad and numerous studies on the development of methods for the isolation of the bases and their analysis are described. Possible ways to use the bases and resources for increasing their production are indicated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1587–1600, December, 1976.