On the magnetic properties and the phase composition of the Cr2O3?MnOx-system (2 ≥ x ≥ 1.5)

The mixed oxide system Cr₂O₃? MnO_x (2 ≥ x ≥ 1.5) was investigated by X-ray diffraction, by measurements of magnetic susceptibility, and by chemical determination of excess oxygen (BUNSEN'S method). The Presence of the antiferromagnetic oxides Cr₂O₃, β-MnO₂, α-Mn₂O₃ and a ferromagnetic phase Cr_1?yMn_yO₂ was stated. The formation of the latter with fourvalent chromium is explained by a lattice induction effect of the MnO₂ (rutile type).     

Frequency distribution of radiation emitted from excited atomic systems

General expressions for the time-dependent probability amplitudes of the quantum states of two arbitrary, interacting atoms are calculated when one atom is initially in an excited p state and the other atom is in an s ground state. The lifetimes of the excited states and the line shape of the emitted radiation are obtained as functions of both the atomic separation and the energy difference between the excited states of the two atoms. The emission line shape is shown to be doubly peaked and to agree with the line shape of the radiation scattered by a system of two interacting atoms. The expressions for the lifetimes of the excited states are found to be identical to those obtained for the radiation scattering situation.     

Cl35 NQR spectra and the transmission effects in the series RSO2Cl

Conclusions It was shown by correlating the Cl³⁵ NQR frequencies with the Taft _I and _c parameters that the effect of substituents, which are either capable of conjugation (Hal, OR, NR₂) or are alkyl groups, is transmitted to the chlorine atom through the SO₂Cl group by a practically purely inductive means.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 486–488, February, 1970.     

Me?ger?t und Verfahren zur Auswertung hochaufgel?ster Massenspektren auf Photoplatten

Zusammenfassung Es wird die Auswertung von Massenspektren hoher Auflösung auf Photoplatten beschrieben.Das Auswertegerät projiziert einen 1×2 cm großen Ausschnitt der Platte auf eine 1×2 m große Fläche. Linienabstände werden mit einem photoelektrischen Längenschrittgeber in Einheiten von 2,5 gemessen. Das Gerät enthält ferner eine Abtastvorrichtung für das Linienprofil zur genauen Lokalisierung der Linien und zur Schwärzungsmessung sowie eine auf eine Masseneinheit genaue Massenanzeige. Die Einstellung der Linien erfolgt durch geschwindigkeitsgesteuerte Motoren von Hand, alle Meßdaten werden auf Knopfdruck vollautomatisch in digitaler Form ausgedruckt bzw. auf Lochkarten gestanzt.Auswerteverfahren unter Benutzung von Tischrechenmaschine oder Computer sowie Meßergebnisse werden diskutiert.

---

Summary The evaluation of high-resolution mass spectra from photographic plates is described.The measuring apparatus projects a part of the plate (1×2 cm) onto a 1×2 m plane. Line distances are measured with a photoelectric device giving pulses for every 2.5 motion of a scale. In addition the apparatus contains a scanning device measuring the density profile across a line or a multiplet for localisation of a line and measurement of density and a unit which indicates the mass number with an accuracy of one mass unit. Adjustment of lines on a mark is done manually with the aid of speed-controlled motors. All measured data are automatically printed or punched in digital form by operation of a push-button.Methods of evaluation of data using a desk calculator and a computer are given and results are discussed.

---

---

Der Vortrag in Lindau enthielt einen Überblick über den derzeitigen Stand der Datenerfassung und -verarbeitung für hochaufgelöste Massenspektren. Dieser Teil des Vortrages ist im wesentlichen enthalten in einem Bericht von D. Henneberg u. G. Schomburg: diese Z. 220, 192 (1966).     

Quantenchemische Untersuchung der Reaktionsfähigkeit von π-Elektronen-Systemen in angeregtem Singulett- und Triplettzustand

Zusammenfassung Anhand der Methode der Konfigurationenwechselwirkung wurde die Ladungsdichteverteilung in einer Reihe von aromatischen Aminen und N-haltigen Heteroaromaten im angeregten Singulett- und Triplettzustand untersucht. Durch die Untersuchungen wurde die Formulierung der folgenden Regel ermöglicht: im angeregten Singulett- und Triplettzustand ist die Basizität bei den Aminen wesentlich vermindert; die N-haltigen Heteroaromaten weisen im angeregten Singulettzustand eine erhöhte Basizität auf, und im Triplettzustand tritt eine Verminderung der Basizität ein.

---

The electron density distribution in excited singlet and triplet states of a number of aromatic amines and heterocyclic compounds containing nitrogen atoms is studied using the CI-method. The investigation allows the formulation of the following rule: in excited singlet and triplet states the amines possess significantly reduced basicity; the nitrogen heterocyclic compounds in excited singlet states increase their basicity, whereas in excited triplet states their basicity is decreased.

---

Résumé Au moyen de la méthode d'interaction de configuration, on a étudié la répartition de la densité électronique dans un certain nombre d'aminés aromatiques et de composés hétérocycliques azotés dans l'état excité singulet et triplet.Les études effectuées ont permis d'établir la règle suivante: à l'état excité singulet ou triplet la basicité des aminés est sensiblement réduite; la basicité des composés N-hétérocycliques augmente dans l'état excité singulet et diminue dans le triplet.

     

Chloridionenübergänge in Phenylphosphoroxychlorid, 3. Mitt.: Konduktometrische Untersuchungen

Zusammenfassung Leitfähigkeitsmessungen an Et₄NCl-Lösungen zeigen die Gültigkeit derBjerrumschen Theorie in PhPOCl₂; die Dissoziationskonstante beträgt 1,5·10^–2. FeCl₃ verhält sich nicht wie eine Ionenverbindung, doch ähnlich wie in POCl₃. Zur Verfolgung von Ionenreaktionen wurden konduktometrische Titrationen ausgeführt. ZnCl₂ und AlCl₃ geben 2 Chloridionen, BCl₃, TiCl₄, SnCl₄ und PCl₅ je 1 Chloridion an die Akzeptoren FeCl₃ oder SbCl₅, ab. In Gegenwart von polaren Chloriden nehmen BCl₃, AlCl₃, FeCl₃, PCl₅ und SbCl₅ je 1 Chloridion, ZnCl₂, TiCl₄ und SnCl₄ je nach Angebot 1 oder 2 Chloridionen auf. Sowohl die Chlorometallate, als auch die Chloroniumverbindungen sind im gleichen Ausmaß wie Et₄NCl ionisiert.Mit 4 Abbildungen2. Mitt.:M. Baaz, V. Gutmann, M. Y. A. Talaat undT. S. West, Mh. Chem.92, 150 (1961).Herrn Prof. Dr.L. F. Audrieth zum 60. Geburtstag gewidmet.     

Cycloaddition of carbonyl compounds on Si(100): new mechanisms and approaches to selectivity for surface cycloaddition reactions

Density functional theory has been used to explore cycloaddition reactions of organic molecules containing carbonyl functional groups on the Si(100) surface. As with other pi bonds, carbonyl groups can add to the surface by a [2+2] cycloaddition with negligible activation barrier, as previously shown through experiment. However, the present calculations indicate that 1,2-dicarbonyls, such as glyoxal, may also react by means of a [4+2] addition to form a hetero-Diels-Alder product in which the organic ring stands normal to the surface. Calculations of [2+2] and [4+2] pathways indicate that both reactions proceed without significant barriers. This reactivity is analogous to that of conjugated dienes, in which evidence for both reactions has been observed. In contrast to unsaturated alkyl systems, which must react through the pi electron system, the reactions of carbonyls may proceed through a very different mechanism, in which the initial surface interaction is through the oxygen lone pair. The presence of lone pairs affects the geometry of the [4+2] adduct, and may alter the competition between [2+2] and [4+2] addition. Some potential rearrangement reactions of the initial binding products are described. Recent experimental studies of a 1,2-dicarbonyl on Si(100) are reinterpreted in light of these calculations, and found to be consistent with the presence of the [4+2] adduct. Finally, some molecules are suggested as cycloaddition reagents for experimental tests of the conclusions presented here.     

Assessment of the retention properties of poly(vinyl alcohol) stationary phase for lipid class profiling in liquid chromatography

Potentialities of polymerized vinyl alcohol on silica gel were assessed for class separation of simple lipids, sphingolipids, glyceroglycolipids and phospholipids by high-performance liquid chromatography. A screening of pure solvents in binary gradient elution and a chemometric approach was used to define a rugged two segment linear gradient formed from four solvents for total lipid class separation. Triethylamine and formic acid were added in all mobile phase components for acidic phospholipid separation and evaporative light scattering response enhancement. Simple analytical procedures are described for the analysis of complex lipid materials.     

New Synthetic Approaches to Functionally Substituted 4,5-Dihydro-1,2,3-oxadiazole 2-Oxides

A practical procedure has been proposed for the synthesis of functionally substituted 4,5-dihydro-1,2,3-oxadiazole 2-oxides on the basis ofsulfamic acid derivatives.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 121–123.Original Russian Text Copyright © 2005 by Tartakovskii, Ermakov, Strelenko, Vinogradov, Petrov.