Heterocyclic analogs of pleiadiene. 70. Synthesis of 6-hydroxy-1,3-diazapyrenes

The regioselectivity of the reactions of perimidine with cinnamic acids in polyphosphoric acid (PPA) depends on the P₂O₅ content. Procedures were developed for the synthesis of 4(9)- and 6(7)-cinnamoylperimidines. Cyclization of the latter under the action of an excess of AlBr₃ was accompanied by dearylation to form 6-hydroxy-1,3-diazapyrene.     

Phase and extraction equilibria in the antipirin-pyrocatechol-water system

Solubility isotherms of the antipirin-pyrocatechol-water ternary system at 25 and 50°C were constructed. A field where two liquid phases are present in equilibrium which results from the protolytic interaction between the components was revealed. The various-composition chemical compounds that formed were isolated preparatively. Interphase distribution of a series of metal ions was studied. The half-extraction pHs of rare-earth metals were found to be linearly related to their ionic radii.     

The determination of bound nitrogen in uranium hexafluoride with an ammonia electrode

Uranium hexafluoride reacts with nitrosyl fluoride (NOF), nitryl fluoride (NO₂F), and nitrogen oxides to form solid compounds such as nitrosyl heptafluorouranate (NOUF₇) and nitryl heptafluorouranate (NO₂UF₇). Since these compounds are undesirable impurities in uranium hexafluoride, a method has been developed for the determination of these nitrogen oxyfluorides in uranium hexafluoride. Uranium hexafluoride is hydrolyzed in a potassium permanganate solution which converts the uranium hexafluoride to uranyl fluoride and the nitrogen oxyfluorides to nitric acid. The nitrate is reduced with aluminum powder to ammonia, which is then measured with an ammonia electrode in a basic solution. The method is relatively interference-free because the electrode is a gas-sensing device. The detection limit is 0.8 μg bound N/g U, and the precision at 3 μg bound N/g U is ± 16%.     

Farbe und Konstitution bei anorganischen Feststoffen, 12. Mitt.: Die Lichtabsorption des zweiwertigen Kobalts in oxidischen Koordinationsgittern vom Ilmenittyp

Zusammenfassung Die Systeme Co _x Mg _1-x TiO₃ (I) und Co _x Cd _1-x TiO₃ (II) wurden röntgenographisch und spektralphotometrisch untersucht. I stellt eine lückenlose Mischkristallreihe dar. Mit wachsendemx nehmen bei I die Gitterkonstantena ₀undc ₀geringfügig zu und die drei Hauptabsorptionsbanden verschieben sich ein wenig in Richtung IR. In II liegt keine lückenlose Mischkristallreihe vor. Sowohl röntgenographisch als auch spektralphotometrisch wurde für die an CoTiO₃ gesättigte CdTiO₃-Phase die Zusammensetzung Co_0,3Cd_0,7TiO₃ (II a) und für die an CdTiO₃ gesättigte CoTiO₃-Phase die Zusammensetzung Co_0,8Cd_0,2TiO₃ (II b) gefunden.Beim Übergang III (x=0,1) wird eine beträchtliche IR-Verschiebung beobachtet. Die IR-Verschiebung ist die Folge der Gitteraufweitung bei der Substitution von Mg²⁺ durch Cd²⁺. Hierbei nimmt derRacah-Parameter geringfügig zu infolge Verminderung der covalenten Anteile der Bindung Co-O.

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The systems Co _x Mg _1-x TiO₃ (I) and Co _x Cd _1-x TiO₃ (II) had been investigated spectrophotometrically and by X-ray diffraction. I represents mixed crystals without any miscibility gap. An increase ofx causes a small enhancement of the lattice unitsa ₀andc ₀of I and the three main absorption bands will be shifted slightly towards IR. II are mixed crystals with a broad miscibility gap. Spectrophotometrically and by X-ray diffraction it could be found that the CdTiO₃-phase saturated with CoTiO₃ and the CoTiO₃-phase saturated with CdTiO₃ have the compositions Co_0,3Cd_0,7TiO₃ (II a) and Co_0,8Cd_0,2TiO₃ (II b), respectively. The transition III (x=0,1) produces a considerable shift of the main absorption bands towards IR as a consequence of the expansion of the lattice caused by the substitution of Cd²⁺ for Mg²⁺. This shift is accompanied by a small increase of theRacah-Parameter owing to a decrease of covalency of the bonding Co-O.

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Mit 4 Abbildungen

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11. Mitt.:D. Reinen, Mh. Chem.96, 730 (1965).     

Electronic Structure, Aromaticity, and Physicochemical Characteristics of Carbene, Radical, and Ionic Forms of Compounds of the Imidazole Series, and their Oxo and Thio Analogs

The effects of benzannellation, phenyl substitution at the nitrogen atom, protonation at the carbene carbon, ionization, and the state of the carbene center (² or ²) on the electronic structure, diamagnetic susceptibility, induced -electron ring currents, the ¹H, ¹³C, and ¹⁴N chemical shifts, and the energies of the lowest electronic transitions of imidazol-2-ylidenes and their oxo and thio analogs were examined in the bound version of -electron perturbation theory. The calculated and experimental data are compared.     

A gas-phase electron diffraction study op the molecular structure of 1,1,1,2-tetrafluoroethane

The molecular structure of 1,1,1,2-tetrafluoroethane is studied using gas-phase electron diffraction data collected on the Balzers KDG2 instrument. Effective least-squares refinement of the geometry is achieved with values for vibrational amplitudes transferred from normal coordinate calculations on related molecules. The following values for the main independent geometrical parameters are obtained (r_a values with e.s.d. in parentheses): C-C = 1.501(4) Å, C-H = 1.077 (15) Å, C-F(CH₂F) = 1.389(6) Å, C-F(CF₃) = 1.334 (2) Å, ∠CCH= 106.1(12)°, ∠CCF(CH₂F)= 112.3(4) Å, ∠CCF(CF₃)= 110.4(2). Other angles are ∠FCF = 108.6 (2)° and ∠FCH = 111.4(15)°, with ∠HCH constrained at 109.4°. The r_a bond lengths of all the fluoroethanes are compared.     

Stereochemie von Metallocenen, 30. Mitt.: Optisch aktive [3]- und [3][3]Ferrocenophane, 3. Mitt.: Zur Konformationsanalyse von [3]Ferrocenophanen (51. Mitt. über Ferrocenderivate)

Zusammenfassung Die Dipolmomente und die Temperaturabhängigkeit derNMR-Spektren sowie des Circulardichroismus der Ferrocenbande von optisch aktiven [3]Ferrocenophanen wurden gemessen. Die Ergebnisse zeigten, daß Substituenten (wie CH₃) in -Stellung zur Brücke bevorzugte Konformationen derselben bedingen, wobei im Vergleich zur -Substitution (die praktisch keinen Einfluß ausübt) die Aktivierungsenergie der Inversion stark erhöht wird. Diese bevorzugten Konformationen bestimmen auch die optische Aktivität der Ferrocenbande.

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Stereochemistry of metallocenes 30. (Ferrocenes, 51). Optically active [3] and [3][3]ferrocenophanes. 3: Conformational analysis of [3]ferrocenophanes

The dipol moments and the temperature dependence of theNMR spectra as well as of the circular dichroism of the ferrocene band of optically active [3]ferrocenophanes were measured. The results revealed that substituents (such as CH₃) in -position with regard to the bridge cause preferred conformations (of the bridge); thereby the energy of activation of the inversion as compared with -substitution (which exerts practically no influence) is strongly increased. These preferred conformations determine also the optical activity of the ferrocene band.

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Mit 1 Abbildung

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29. Mitt., zgl. 50. Mitt. über Ferrocenderivate:H. Falk, Ch. Krasa undK. Schlögl, Mh. Chem.100, 1552 (1969).

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2. Mitt.:H. Falk undO. Hofer, Mh. Chem.100, 1540 (1969).     

Umsetzung elektrisch neutraler organischer Lewissäuren mit Hydrazin

Zusammenfassung Während verschiedene Basen mit organischen Lewissäuren stabile Anbadone liefern, führt die Umsetzung mit Hydrazin zu Aldazinen bzw. Hydrazonen.

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Reaction of electrically neutral organic lewis acids with hydrazine (organic lewis acids, XIV)

While several bases reacting with organic Lewis-acids form stable anbadons, the reaction with hydrazine leads to aldazines (azines) and hydrazones.

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13. Mitt.:P. Margaretha undO. E. Polansky, Mh. Chem.100, 576 (1969).