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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 394 (1972), S. 171-186 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Amino-diphosphazenes III undergo cyclocondensation reactions when heated with phosphorus(III) compounds which bear at least two nucleofugic leaving groups. However, instead of the expected cyclotriphosphaza-dienes IV, cyclotriphosphaza-trienes V containing hydrogen bonded to phosphorus are produced. Although only V was spectroscopically identified (IR, 1H- and 31P-NMR), the existence of IV at equilibrium was demonstrated by the ease of electrophilic substitution of hydrogen by methyl iodide. The unusual prevailing of the PH-form V over the NH-form IV must be explained by extra stabilisation through formation of the cyclophosphazene π system.
    Notes: Aminodiphosphazene III gehen mit Phosphor(III)-Verbindungen. die mindestens zwei nukleophil verdrängbare Reste enthalten, eine Cyclokondensation ein. Statt der dabei zu erwartenden Cyclotriphosphaza-diene IV entstehen Cyclotriphosphaza-triene V mit phosphorständigem Wasserstoff. Während spektroskopisch nur diese Form nachweisbar ist, wird in der elektrophilen Substitution des Wasserstoffs durch Methyljodid doch auch eine Gleichgewichtsbeteiligung von IV erkennbar. Die ungewöhnliche Begünstigung des PH-Prototropen V läßt auf einen erhöhten Energiebeitrag der Phosphazenbindung im cyclisch alternierenden System, d. h. auf eine Extrastabilisierung durch die Ausbildung des Cyclotriphosphaza-triens schließen.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0044-2313
    Keywords: Diphosphene dimerization ; Ylide substituents, Cyclotetraphosphine structure, 31P-NMR spectra analysis, Transanular electron lone pair interaction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Bis(triphenylphosphonium-ylidyl)cyclotetraphosphinesThe title compounds 3a, b result from the condensation of the ylidyldichlorophosphines Ph3PCR—PCl2 1a, b (R = Me, 3-Tol) with phenyl bis(trimethylsilyl)phosphine 2. Analysis of the 31P-NMR spectra and the X-ray structure investigation of 3a demonstrate a folding of the four-membered ring and an all-trans orientation of the substituents.
    Notes: Die Titelverbindungen 3a, b entstehen durch Kondensation der Ylidyldichlorphosphane Ph3PCR—PCl2 1a, b (R = Me, 3-Tol) mit Phenyl-bis(trimethylsilyl)phosphan 2. Die Analyse der 31P-NMR-Spektren und die Röntgenstrukturbestimmung von 3a zeigen eine Faltung des Vierrings und all-transständige Substituenten.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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