NMR spectra and conformation of cembrene in solution

Using dimeric NMR spectroscopy, a complete interpretation of the¹H and¹³C NMR spectra of the diterpene hydrocarbon cembrene has been made. The experimental values of the SSCs for the¹H atoms in the PMR spectra of cembrene agree well with those calculated for the lowest-energy (“crystal”) conformation. In the light of the observation of intramolecular NOEs and of the low-temperature¹³C NMR spectra, it has been concluded that the cembrene molecule retains the “crystal” conformation in solution.     

Transverse dislocation analog of the Nernst-Ettingshausen effect in ionic crystals

We show that in ionic crystals under the action of a temperature gradient and an external magnetic field on the cloud of point defects surrounding a charged dislocation, a phenomenon arises which is analogous to the Nernst-Ettingshausen effect.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 80–83, January, 1996.     

Nonstationary shear flow of a viscoplastic medium

We consider problems involving nonstationary shear flow of a viscoplastic medium between two parallel plates and also in a cylindrical tube under the action of a time-varying shear stress applied to the walls of the passage.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 4, pp. 133–137, July–August, 1972.     

NMR spectra and conformation of cembrene in solution

Using dimeric NMR spectroscopy, a complete interpretation of the¹H and¹³C NMR spectra of the diterpene hydrocarbon cembrene has been made. The experimental values of the SSCs for the¹H atoms in the PMR spectra of cembrene agree well with those calculated for the lowest-energy (crystal) conformation. In the light of the observation of intramolecular NOEs and of the low-temperature¹³C NMR spectra, it has been concluded that the cembrene molecule retains the crystal conformation in solution.Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR, Novosibirsk. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 455–459, July–August, 1991.     

Composition,properties, and structure of palladium(II) chlorides in aqueous solution

The composition, stability, and structure of palladium(II) chloride complexes in hydrochloric acid media have been determined using nuclear-magnetic relaxation, magnetochemical methods, and Rayleigh light scattering. The predominant form in solution for palladium(II) concentrations greater than 0.005 moles/liter is the octahedral Pd₆Cl₁₂ or Pd₆Cl₁₄ ^2–, which has antiferromagnetic properties in contrast with the paramagnetic properties of the mononuclear aquachloride. The polarizability anisotropy of Pd-Cl bonds with terminal and bridging chlorine atoms has been determined.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2473–2477, November, 1990.     

Influence of Sodium Dodecyl Sulfate on the Protolytic Properties of N,N-Dimethyl-N′-(2-hydroxybenzyl) Ethylenediamine and Its Complexation with Copper(II)

To investigate the effect of sodium dodecyl sulfate (concentration C _s = 5 and 10 mM) on the acid–base properties of N,N-dimethyl-N-(2-hydroxybenzyl) ethylenediamine and its complexation with copper(II) (C _s = 10 mM) was studied using the methods of potentiometry, spectrophotometry (at 298 K), and mathematical simulation of equilibria in solutions. The sodium dodecyl sulfate contributes to the formation of a monomeric form of N,N-dimethyl-N-(2-hydroxybenzyl)ethylenediamine, while this compound exists in 40% isopropyl alcohol predominantly in the form of a dimer. The acidic properties of protonated monomeric and dimeric species are weaker than those in an aqueous alcohol solution. Sodium dodecyl sulfate facilitates the coordination of the deprotonated form of ligand. The region of the predominant accumulation of an uncharged complex of 1 : 2 composition is shifted to lower pH values (11.0 and 7.5, respectively), whereas the molar absorption coefficient of the complex increases by approximately 1.7 times. The apparent stability constants of complexes of the same type increase.     

Structure of dysprosium monotartrate in aqueous solution from magnetic double refraction and molecular mechanics data

pH-Metering and magnetic double refraction are used to determine the molar constant of magnetic double refraction of dysprosium monotartrate DyH₂L⁺ (H₄L is tartaric acid). A molecular mechanics technique (Dashevskii-Plyamovatyi model) was used to model the structure of the ligand and hydrate surroundings of dysprosium(III) in DyH₂L⁺. Theoretical molar constants of magnetic double refraction calculated from the molecular mechanics data (CONKERR program) were compared with the experimental values; the most probable models of the surroundings of the dysprosium(III) are established.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Research Center, Russian Academy of Sciences, 420062 Kazan'. V. I. Ul'yanov-Lenin Kazan' State University, 420008 Kazan'. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2232–2237, October, 1992.     

Change in Volume Properties of and Complex Formation in the System Hg(NO3)2-KX-H2O (X- = Cl-, Br-, I-)

The chemical nature of the anions in step complex formation in Hg(NO₃)₂-KX-H₂O systems (X^- = Cl^-, Br^-, I^-) manifests itself in different trends in variation of the molar volumes of the solutions.