A novel heteropolycyclic system from n-methylquinoxalinium iodide and nitroethane

Reaction of N-methylquinoxalinium iodide with nitroethane results in either the 1:2 diadduct at C-2 and C-3 or the formation of substituted 1,3,6,10-tetraazatetracyclo[7.3.1.0.^2,70^6,13] tridecane derivative.     

Die untersuchung von adsorptionsgleichgewichten auf graphitiertem thermischen ruß mittels gas-chromatographie

Zusammenfassung Auf der Oberfl?chevon graphitiertem themischen Ru? werden im Grenzgebiet kleiner Belegungen die Retentionsvolumina und Adsorptionsw?rmen der Alkane, Alkene, Alkadiene, Alkine, Cyclane,Cyclene von C₁−C₆ und Benzol bestimmt. Es werden die Abh?ngigkeiten der Adsorptionsw?rmen dieser Moleküle von ihren Polarisierbarkeiten Zhal der Kohlenstoffatome, Grad der Verzweigung und Cyclisierung, Anwesenheit von Doppelbindungen und konjugierten Bindungen untersucht.

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Gas chromatographic investigation of the adsorption equilibrium on graphitized thermal carbon black I. The henry-constants and heats of adsorption of C₁−C₆ hydrocarbons at zero coverage

Summary The retention volumes and heats of adsorption at low surface coverages of graphitized thermal carbon black for C₁−C₆ alkanes, alkenes, alkadienes, alkynes, cyclanes, cyclenes, and benzene have been determined. The dependence of heats of adsorption of these molecules on polarisability, carbon number, isomerisation and cyclisation, the presence of double bonds and conjugated bonds were investigated.

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Etude par la chromatographie en phase gazeuse de l'équilibre d'adsorption sur le noir de carbone graphitisé par voie thermique I. constante de henry et enthalpie d'adsorption des hydrocarbures en C₁ à C₆ pour les taux de recouvrement nuls

Résumé On a déterminé les volumes de retention et les enthalpies d'adsorption des molécules d'alcanes, alcènes, alcadiènes, alcynes, cyclanes, cyclènes en C_` à C₆ et du benzène sur la surface du noir de carbone graphitisé par voie thermique pour les taux de recouvrement faibles. On a aussi étudié la relation entre les enthalpies d'adsorption de ces molécules et leur polarisabilité, leur nombre d'atomes de carbone, la ramification de leur cha?ne, la cyclisation, le nombre de doubles liaisons et de doubles liaisons conjuguées.

     

Electrical resistance and thermophysical properties of solid solutions of germanium in iron

Temperature dependence of thermal diffusivity, thermal conductivity, and electrical resistance is studied in solid solutions of germanium in iron at impurity concentrations of 0.49–18.0 at.% Ge over the temperature range 300–1300K. The results obtained are evaluated and compared to similar dependences for the system Fe-Si.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 36–41, June, 1984.     

Intramolecular Dynamics and Molecular Structure of Europium(III) Chelate Complexes with Crown Ethers as Studied by NMR Spectroscopy

Earlier the intramolecular inversion of the 18-crown-6 molecules was found in the complex ion pairs [Ln(ptfa)₂ (18-crown-6)]⁺ [Ln(ptfa)₄]⁻ (H₂O)₄ where Ln = La(1), Ce (2), Pr (3), Nd (4), and ptfa is 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione. In this work the peculiarities of the molecular structure and dynamics were studied for [Eu(ptfa)₂ (18-crown-6)]⁺ [Eu(ptfa)₄]⁻ (H₂O)₄ (5) by NMR spectroscopy techniques. Through VT-NMR spectra analysis the temperature dependence was obtained for the rate constant. The free energy ΔG^‡(320) of 18-crown-6 ring inversion activation was found to be 65 ± 5 kJ mol⁻¹ for 5 in CDCl₃. This result is comparable with the earlier data [S.P. Babailov and D.A. Mainichev: J. Inclusion Phenom. Macrocyclic Chem. 43, 187–193 (2002)] for complexes 2, 3, 4 in deuterated toluene (ΔG^‡(320)=65 ± 9, 64 ± 9, 64 ± 9 kJ mol⁻¹ respectively). It was found by relaxation NMR spectroscopy that the effective distance between Ln and protons of the crown molecule is 4.5 ± 0.2 Å. The analysis of structural parameters testifies that the crown ether and chelated anions are in the first coordination sphere of a Ln cation. Obtained geometrical parameters show that the complex cations of Eu, Ce and Pr have similar spatial structures.This revised version was published online in July 2005 with a corrected issue number.     

[(4,4‐Dimethyl‐2‐oxo‐1,3‐oxazolidin‐3‐yl)methyl]phosphonic acid

The title compound, C₆H₁₂NO₅P, was synthesized as an inter­mediate phase in a search for new N‐(phosphono­methyl)glycine derivatives. The mol­ecules are held together by O—H⋯O hydrogen bonds, forming chains along the b axis in the crystal structure. The observed mol­ecular structure is compared with that calculated by the density functional theory method.     

Replacement of an oxygen atom by chlorine atoms in the reaction of pentafluorobenzaldehyde with CCl3-substituted compounds in the presence of AlCl3

The interaction of pentafluorobenzaldehyde with RCCl₃ (R = Cl, Ph, C₆F₅) in the presence of threefold molar excess of AlCl₃ proceeds with replacing the oxygen atom of the aldehyde group by two chlorine atoms from the CCl₃ group and results in the formation of pentafluorobenzylidene chloride. The electrophilic mechanism of the reaction is proposed.