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  • 1
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deactivation Behaviour of Arenes and Heteroarenes. XXXVI. The Solvent and Temperature Dependence of Deactivation Behaviour of 9, 9′-Bis(acridizinium-yl) at High ConcentrationAt room temperature the geometrical structure of the fluoresceing singlet state of 9, 9′-bis(acridizinium-yl) is determined by the solvent. In solvents of the type A (water, methanol, acetonitril) a plain S1-state emits, in the case of the solvent type B (ethanol, propanol-(2)) the S1-state is twisted. Both excited states have different emission spectroscopical properties.At high concentration (c ≥ 10-4 mol l-1) in the case of the solvent type B a new emission band is observed, and the monomer emission is quenched. This new band is interpreted as a fluorescence from a molecular associate in the excited state. The intensity of this associate band is increasing with decreasing temperature. It is shown that this band is the result of molecular association in the ground state. From the photochemical irradiation it follows that only in the case of the solvent type B a photocycloaddition is possible. The plain S1-state does not react.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 34 (1983), S. 328-331 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: 2,2′-azo-bis-isobutyronitrile was completely thermally decomposed in allyl benzene. The reaction mixture obtained was separated by preparative gas and thin-layer chromatography. Using steam pressure measurements and the logarithmic dependence of gas chromatographic retention value of the molecular weight the molecular weight of the separated components was investigated. The structure was analysed by IR- and NMR-spectroscopy and 14C-labelled tracer substances. A mechanism of the reactions is discussed.
    Notes: 2,2′-Azo-bis-isobutyronitril wurde in Allylbenzen thermisch vollständig zersetzt. Das entstehende Reaktionsgemisch konnte mit Hilfe der präparativen Gas- und Dünnschichtchromatographie getrennt werden. Die Bestimmung der Molmassen der abgetrennten Komponenten erfolgte über Dampfdruckmessungen sowie über die logarithmische Abhängigkeit der gaschromatographischen Retentionswerte von den Molmassen. Die Konstitutions- und Konfigurationsaufklärung gelang mittels IR- und NMR-Spektroskopie sowie durch Anwendung von 14C-markierten Tracer-Substanzen. Ein möglicher Reaktionsablauf wird diskutiert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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