N‐heterocyclic carbenes. IV.1synthesis of symmetrical and unsymmetrical imidazolium salts with abietane moiety

Methyl 12‐chloromethyl‐dehydroabie‐tate reacts with 1‐benzyl‐ and 1‐arylimidazoles to give unsymmetrically substituted imidazolium chlorides ( 1a–i ), with abietane moiety. Starting from methyl 12‐aminodehydroabietate, symmetrically substituted diterpene‐based salts of imidazolinium ( 4 ) and imidazolium ( 5 ) were synthesized. Anion exchange afforded corresponding ( 1e ·BF₄) and ( 1e ·PF₆). The new compounds were tested as ligands for a Pd‐catalyzed Suzuki‐Miyaura reaction. The molecular structure of ( 1e ) is reported. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:5–15, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20745     

Formation of Carbon Nanostructures in Electrolytic Production of Alkali Metals

Carbon-based solid phase containing open and closed multiwalled carbon nanotubes (up to 5% of the total carbon) was found in the waste from industrial production of metallic lithium by electrolysis of lithium chloride melt with graphite electrodes. __________ Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 12, 2005, pp. 1977–1980. Original Russian Text Copyright ? 2005 by Alekseev, Arapov, Belozerov, Osipov, Semenov, Polovtsev, Charykov, Izotova.     

Feasibility of creating a specialized reactimeter based on the inverse solution to kinetics equation with a current-mode neutron detector

The file-evaluation results of a reactimeter based on the inverse solution to the kinetics equation (ISKE) are presented, which were obtained using an operating hardware-measuring complex with a KNK-4 neutron detector working in the current mode. The processing of power-recording files of the BR-1M, BR-K1, and VIR-2M reactors of the Russian Federal Nuclear Center—All-Russian Research Institute of Experimental Physics, which was performed with the use of Excel simulation of the ISKE formalism, demonstrated the feasibility of implementation of the reactivity monitoring (during the operation of these reactors at stationary power) beginning from the level of ~5 × 10^–4β_eff.     

Extraction Equilibria in the Fullerene C60-Fullerene C70-Solvent Systems

A new method was proposed for separation of light fullerenes C₆₀ and C₇₀ based on realization of two-phase extraction equilibria in multicomponent fullerene-containing systems C₆₀-C₇₀-solvent I-solvent II and C₆₀-C₇₀-solvent I-solvent II-inert component. The principal possibility and high efficiency of the extraction separation of light fullerenes were demonstrated.     

Scaling in the quantum Hall effect regime in n-InGaAs/GaAs nanostructures

The longitudinal ρ _xx (B) and Hall ρ _xy (B) magnetoresistances are investigated experimentally in the integer quantum Hall effect (QHE) regime in n-InGaAs/GaAs double quantum well nanostructures in the range of magnetic fields B = (0–16) T and temperatures T = (0.05–70) K before and after IR illumination. The results are evaluated within the scaling hypothesis with regard to electron-electron interaction.     

Solubility of light fullerenes in vegetable oils

Polythermal (in the temperature range 0−80°C) solubility of light fullerenes (C₆₀ and C₇₀), and also of fullerene mixtures (65% C₆₀, 34% C₇₀, and 1% C_76–90) in vegetable oils (of unrefined and refined sunflower, corn, olive, linen, apricot, grape, cedar, and walnut) was studied; the corresponding solubility polytherms are given and characterized.     

Chemical composition of extracts from shungite and “shungite water”

A chemical analysis of aqueous extracts from shungite-III from the Zazhogino deposit (Republic of Karelia) and of natural water contacting with shungite rocks was made. The chemical composition and bactericide properties of “shungite water” were studied.     

Reconstruction of the 2D hole gas spectrum for selectively doped <Emphasis Type="Italic">p</Emphasis>-Ge/Ge<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>S<Subscript>ix</Subscript> heterostructures

The magnetic field (0≤B≤32 T) and temperature (0.1≤T≤15 K) dependences of longitudinal and Hall resistivities have been investigated for p-Ge_0.93Si_0.07/Ge multilayers with different Ge layer widths 12≤d _w ≤20 nm and hole densities p _s =(1–5)×10¹⁵ m^?2. An extremely high sensitivity of the experimental data (the structure of magnetoresistance traces, relative values of the inter-Landau-level gaps deduced from the activation magnetotransport, etc.) to the quantum well profile is revealed in the cases where the Fermi level reaches the second confinement subband. An unusually high density of localized states between the Landau levels is deduced from the data. Two models for the long-range random impurity potential (the model with randomly distributed charged centers located outside the conducting layer and the model of the system with a spacer) are used to evaluate the impurity potential fluctuation characteristics: the random potential amplitude, the nonlinear screening length in the vicinity of integer filling factors v=1 and v=2, and the background density of states (DOS). The described models are suitable for explanation of the observed DOS values, while the short-range impurity potential models fail. For half-integer filling factors, a linear temperature dependence of the effective quantum Hall effect plateau-plateau (PP) transition widths v₀(T) is observed, contrary to the expected scaling behavior of the systems with short-range disorder. The finite T→0 width of the PP transitions may be due to an effective low-temperature screening of a smooth random potential due to the Coulomb repulsion of electrons.     

The solubility of C<Subscript>60</Subscript>Br<Subscript><Emphasis Type="Italic">n</Emphasis></Subscript> (<Emphasis Type="Italic">n</Emphasis> = 6, 8, 24) in organic solvents

The polythermal (over the temperature range 20–80°C) solubility of fullerene bromo derivatives C₆₀Brn (n = 6, 8, 24) in several solvents (o-xylene, o-dichlorobenzene, n-decanol-1, and enanthic acid) was studied. The corresponding solubility polytherms are given.     

Phase equilibria in the system fullerene C60-hexane-o-xylene-dimethylformamide

Phase diagrams in ternary liquid systems hexane o-xylene DMF were studied at 298.15 333.15 K. Critical points in these systems were determined. The fullerene C₆₀ distribution in the ternary liquid systems with constant and variable compositions of two organic phases was studied at variable fullerene concentration.