Chemical structure of iodine-doped polyisoprene

A nonconjugated conducting polymer (1,4-rans-polyisoprene) at different iodine doping levels has been studied with the 27.7-keV Mössbauer resonance of¹²⁹I. At the light doping level, almost all iodines are covalently bonding to the carbon atoms, breaking the double bonds of the main chain. At the medium doping level, other iodine species are found, which are idendified as anion species, l^?, l ₃ ^? and l ₃ ^? .At the heavy doping level, polyiodide anions, l ₃ ^? and l ₅ ^? , increase as compared to the covalently bonding iodine atoms and addtionally molecular iodine l₂ exists.     

On the role of theΔ -isobar in deep inelastic scattering on the deuteron

The role of the nuclear structure effects, viz. the boundness of nucleons and-isobar components, in the deep inelastic scattering of leptons on the deuteron is considered. It is shown that small admixture of the-isobar configurations to the deuteron wave function may lead to significant effects in the spin structure functions of the deuteronb ₁ ^D andg ₁ ^D (x): up to 4% in g ₁ ^D (x) dx and up to 10% ing ₁ ^D (x) at smallx.One of the authors (A.U.) thanks Prof. F.C. Khanna for helpful discussions and for kind offering the information used in our calculations.     

The effect of angular-momentum dissipation on fluctuations of excitation functions in heavy-ion collisions

We discuss here the effect of dissipation of relative angular momentum on fluctuations of excitation functions in dissipative heavy-ion collisions. Dissipation and fluctuation of relative angular momentum modify and smooth the time-angle localization of the rotating dinuclear system. The secondary maxima in the energy correlation function of the cross-section shift to smaller values of the energy difference, the shift depending on the relaxation time and the diffusion coefficient for angular-momentum dissipation. The results are illustrated for the collision²⁸Si(E _lab=130 MeV)+⁴⁸Ti.Partly supported by the Alexander von Humboldt Foundation     

Influence of manganese admixture on the magnetic properties of CdHgSe

The magnetic susceptibility of Cd_x-Hg_1–x–yMn_ySe(x 0.1, 0 y 0.1) in the temperature range 77–300 K is investigated. According to the usual model, the dependence Mn^–1=f(T) is due to clusters in the form of closely spaced Mn atoms, between which there may be both direct and indirect (through a nonmagnetic atom) exchange interaction, leading to antiferromagnetic ordering.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 65–67, August, 1991.     

Rhombohedral superlattices based on bcc ones: Concentration and displacement waves

Superlattices based on bcc ones are considered that have space groups P 3ml or P3ml and tripled parameters in the initial cubic axes. Expressions are derived for the concentration and displacement waves corresponding to these superlattices.Translated from Izvestiya Vysshikh Uchebynkh Zavedenii, Fizika, No. 9, pp. 91–96, September, 1991.     

Far-infrared radiation effect on the structure and properties of proteins

This paper describes the effect of far-infrared radiation on the activity and secondary structure of albumin, alcohol dehydrogenase, peroxidase and trypsin. For the first time the data obtained allowed a conclusion that enzymatic activity changes under the influence of radiation having the wavelength of 90 m. No disruptures of polypeptide chains or oligomerization of proteins were obtained. It has been shown that albumin secondary structure calculated from circular dichroism spectra changes lineary according to dose of laser emission.Abbreviations FIR far-infarred radiation - CD circular dichroism - ADG alcohol dehydrohenase - PXD peroxidase - ANS 1-anilinenaphalene-8-sulfonic acid     

Formation pathways and structure—Property interrelationship of 3-imino-1-methyl-5,5-dialkyl-4,7,7-tricyano-2-oxabicyclo-[2.2.1]heptane derivatives

The problems of the structure—property interrelationship of 3-imino-2-oxabicyclo[2.2.1]heptane derivatives are discussed on the basis of x-ray diffraction studies (XDS). A pathway for the formation of the bicyclic compounds is proposed, and the realization of spirans in the reaction of sym-tetracyanoethane with conjugated cyclic systems containing s-cis C=C and C=O fragments is substantiated. The factors responsible for the syn orientation of the oxygen atom and the N-substituent of the imino group are analyzed. It is shown that a change in the steric hindrance in the bicyclic compounds leads to a change in the conformation of the latter. The reasons for the shortening of the C_sp3-C_sp3, C_sp3-C_sp and C=N exo bonds and the correlation of the XDS and IR spectroscopic data are examined. From the XDS data for N-bromo-substituted imines, a model for Br⁺...NC electrophilic attack was proposedCommunication 16 from the series Chemistry of 1,1,2,2-tetracyanoethane. See [1] for Communication 15.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 519–526, April, 1991.     

Mechanism of the photoreactions of fulgides based on 1,2-dimethyl-3-formylindole

Only E Z isomerization is observed for the steady irradiation of fulgides based on 1,2-dimethyl-3-formylindole in contrast to the analogs based on 3-acetylindole. The formation of cyclic photoisomers is registered by the method of impulse photolysis. The presence of a methyl substituent in the position 2 of the indole portion leads to a significant increase in the stability of the photochromic system. The introduction of alternative reaction centers of cyclization in the form of bulky phenyl groups leads to the suppression of electrocyclization at the position 2 of the indole portion and the formation of dihydronaphthalene structures.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1255–1258, September, 1991.