Synthesis of halogenoazoles

On reaction with halogens, organolithium and organomagnesium derivatives of azoles are converted into halogenoazoles. Halogen derivatives of N-substituted imidazoles, benzimidazoles, and indazoles have been studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1109–1111, August, 1973.     

Parakristalline Gitterstörungen in Kettenrichtung von Cellulose I und II

Zusammenfassung Röntgenweitwinkelmessungen an Ramie sowie an einer Viskosefaser zeigen, daß in Kettenrichtung parakristalline Störungen vong=1,1% bzw.g=1,5% vorliegen. Die mittleren Kristallitgrößen in Kettenrichtung betragen¯D ₀₁₀=485 Å bzw.¯D ₀₁₀=112 Å, senkrecht dazu etwa¯D=52 Å bzw.¯D=41 Å. Aus Röntgenkleinwinkelmessungen ergeben sich kleinste Fibrillendurchmesser von 2R=52 Å bzw. 2R=45 Å. Die gefundenen Fibrillendurchmesser verhalten sich wie 1248.Für die Viskosefaser wird eine Langperiode vonP=168 Å gemessen, woraus mit¯D ₀₁₀=112 Å folgt, daß die ungeordneten Bereiche in Kettenrichtung eine Länge von etwa 56 Å haben.

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Summary Wide angle X-ray diffraction studies on ramie and on a viscose fibre show that paracrystalline distortions exist in chain direction havingg-values ofg=1.1% andg=1.5%, respectively. The mean crystallite sizes in chain direction are¯D ₀₁₀=485 Å and¯D ₀₁₀=112 Å, respectively. Perpendicular to the chain direction mean crystallite sizes of approximately¯D=52 Å and¯D=41 Å, respectively, are measured.Small angle X-ray diffraction studies give the diameters of the cellulose fibrils, the smallest of which are 2R=52 Å and 2R=45 Å, respectively. The diameters of the fibrils are in the ratio of 1248.A long period ofP=168 Å is measured for the viscose fibre implying a length of 56 Å for the disordered domains in chain direction.

     

Acrylonitr1le anion-radical detection by infrared internal reflection spectra

The application of internal reflection spectroscopy to the study of interface boundary layers has been extended over cases in which unstable particles appear at the interface as a result of imposing a negative electrical potential on the germanium hemicylinder, used simultaneously as an optical prism in the internal reflection spectroscopic device and as an electrode. The appearance of the particles is detected by their internal reflection spectrum. The method has been applied in the case of the electrochemically induced polymerization of acrylonitrile. Two particles were found to be generated during electrolysis. They are assigned to the anionradical and to the di-anion of acrylonitrile.     

Electrical Resistivity and Magnetic Susceptibility Measurements on Copper Arsenides

Electrical resistivity (4.2–800°K) and magnetic susceptibility (4.2–500°K) measurements are carried out on Cu_3–xAs, Cu_5–xAs₂ and the recently obtained, tetragonal Cu₂As. All three compounds appear to be metallic conductors, but have high residual resistances because of the large defect concentrations (resulting from non-stoichiometry and preparation method). Cu_3–xAs is diamagnetic; Cu_5–xAs₂ is Pauli-paramagnetic; Cu₂As has a very small, constant, positive susceptibility above room temperature and a more pronounced Curie-Weiss behaviour at lower temperatures. The Pauli-paramagnetic contributions have been estimated. A slight anomaly in the electric and magnetic behaviour of Cu_3–xAs is observed at 220°K. To clarify the high-temperature phenomena, a series of D.T.A. and X-ray experiments has also been carried out.     

PPP-Berechnungen und Vergleich der Elektronenspektren von iso-π-elektronischen Sauerstoff-, Stickstoff-, Schwefel- und Selenheterocyclen

Zusammenfassung 42 Heterocyclen, die sich formal von alternierenden und nichtalternierenden Kohlenwasserstoffen durch Ersatz einer Doppelbindung durch die Heteroatome Sauerstoff, Stickstoff, Schwefel und Selen ableiten, werden nach dem Pariser-Parr-Pople-Verfahren berechnet und ihre Spektren im nahen Ultraviolett und Sichtbaren beschrieben. Schwefel und Selen werden dabei im LCAO-MO-Verfahren nach dem p-Modell behandelt. In den meisten Fällen können die Berechnungen nicht nur die spektralen Charakteristika gut wiedergeben, sondern auch Beziehungen in den Spektren iso--elektronischer Verbindungen gleicher Struktur verständlich machen. Berechnungen an kationischen Stickstoffheterocyclen führten dann zu falschen Ergebnissen, wenn die Stickstoffparameter vom Pyrroltyp übernommen werden.

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PPP-calculations and comparison of electronic spectra of iso--electronic oxygen, nitrogen, sulfur, and selenium heterocycles

42 heterocyclic compounds, formally derived from alternant or nonalternant hydrocarbons by replacing a C=C group by an oxygen, nitrogen, sulfur or selenium atom, are studied by the Pariser-Parr-Pople-type of calculation. By means of these results the near ultraviolet and visible spectra are described. The sulfur and the selenium atoms are treated in the LCAO-MO-method using the p-model. In most cases spectral features are not only well reproduced, but interrelations of the spectra of iso--electronic compounds, possessing analogous structures are interpreted, too. On calculating cationic nitrogen heterocycles using parameters of pyrrol type nitrogen results are unsatisfactory.

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Résumé 42 composés hétérocycliques, formellement dérivés d'hydrocarbures alternants ou non alternants par remplacement d'un groupement C=C par un atome d'oxygène, d'azote, de soufre ou de sélénium, sont étudiés par la méthode de Pariser-Parr-Pople. Les résultats obtenus permettent de décrire le spectre U.V. proche et visible. Soufre et sélénium sont traités en utilisant le modèle p. Dans la plupart des cas les caractères spectraux sont non seulement correctement reproduits, mais les relations entre les spectres des composés iso--électroniques à structures analogues peuvent être interprétées. Les calculs concernant les heterocycles à azote cationique sont insatisfaisants lorsqu'ils sont effectués avec des paramètres de l'azote du type pyrrole.

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Anmerkung: Die Arbeit wurde in dem von Prof. Dr. R. Mayer geleiteten Schwefelarbeitskreis der TU Dresden durchgeführt.