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  • Wiley-Blackwell  (8)
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  • Wiley-Blackwell  (8)
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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 13-41 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polycyclic Triaryldioxyphosphoranes of Extreme StabilityThe phosphoranes 1a-d, 27, 32 containing the [1,2]oxaphospholo[4,3,2-hi][2,1]benzoxaphosphole skeleton are very stable constitutively as well as conformationally, in contrast to their acyclic analogues. This is already shown by their unexpectedly easy formation starting from phosphine oxide precursors (phosphine oxide acetalization). In this series, even the derivative 22 with a diequatorial 2,2′biphenylylene system is of considerable stability. In no case, defined thermolysis reactions could be observed. Very favorable steric conditions of the educt on the one hand and steric and electronic restrictions with respect to the potential reaction paths and reaction products on the other hand are responsible for this behavior. In the case of the spirophosphorane 30 possessing two 2,1-benzoxaphosphole entities, no hints for the isomeric phosphorane 29 with an oxaphospholo-benzoxaphosphole skeleton could be found. To complete the spectrometric relationships (31P, 1H, 13C NMR; IR; MS) the spirophosphoranes 33, 34 were also synthesized.
    Notes: Die Phosphorane 1a - d, 27, 32 mit [1,2]Oxaphospholo[4,3,2-hi][2,1]benzoxaphosphol-Gerüst sind im Gegensatz zu ihren acyclischen Analoga konstitutiv wie auch konformativ sehr beständig, was sich bereits in ihrer unerwartet bereitwilligen Bildung aus z. B. Phosphinoxid-Vorstufen (Phosphinoxid-Acetalisierung) äußert. In dieser Reihe ist sogar das Derivat 22 mit diäquatorialem 2,2′;Biphenylylen-System von beachtlicher Stabilität. In keinem Fall konnten definierte Thermolysereaktionen beobachtet werden, wofür einerseits die sehr günstigen sterischen Voraussetzungen auf der Eduktseite, andererseits sterische und elektronische Restriktionen bezüglich der potentiellen Reaktionswege und -produkte verantwortlich gemacht werden. Im Falle des zwei 2,1-Benzoxaphosphol-Einheiten aufweisenden Spirophosphorans 30 konnten keine Hinweise auf das isomere Phosphoran 29 mit Oxaphospholobenzoxaphosphol-Gerüst gefunden werden. Zum Spektrenvergleich wurden noch die Spirophosphorane 33, 34 synthetisiert.
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  • 2
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Racemization of Spirocyclic Pentaaryl Derivatives of Group 5 A Elements, II. Racemization of Optically Active 2-Biphenylyl(2,2′-biphenylylene)(4-methyl-2,2′-biphenylylene)phosphoraneThe racemization of the optically active title phosphorane 2 gave the following activation parameters: ΔH≠ = 26.2 ± 1 (109.5 ± 4.4), ΔG≠298 = 27.6 ± 2(115.7 ± 8.2)kcal(kJ)/mol and ΔS≠ -4.9 ± 3.1 (-20.6 ± 13) cal(J)/K · mol. As racemization mechanism a pseudorotation process is discussed which goes through a trigonal bipyramidal transition state with a diequatorial 2,2′- biphenylylene group.
    Notes: Die Racemisierung des optisch aktiven Titelphosphorans 2 lieferte folgende Aktivierungsparameter: ΔH≠ = 26.2 ± 1 (109.5 ± 4.4), ΔG≠298 = 27.6 ± 2(115.7 ± 8.2) kcal(kJ)/mol und ΔS≠ = -4.9 ± 3.1 (-20.6 ± 13) cal(J)/K mol. Als Racemisierungsmechanismus kommt ein Pseudorotationsprozeß in Frage, bei dem ein trigonal-bipyramidaler Übergangszustand mit diäquatorialer 2,2′-Biphenylylen-Gruppe durchlaufen wird.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1786-1792 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Intramolecular Cycloaddition Reactions of Phosphorus ylides; 8,13-Methano-5H-dibenzo[b,a]phosphonin Derivatives[Bis(2-isopropenylphenyl)phenylphosphonio]- and [tert-butylbis(2-isopropenylphenyl)phosphonio]methanide (8a and b) rearrange in 2-3 days to give the isomeric phosphanes 6,7,8,13-tetrahydro-8,13-dimethyl-5-phenyl(or-5-tert-butyl)-8,13-methano-5H-dibenzo[b, e]phosphonin (13a and b). The structure of 13a, was proven by x-ray analysis.
    Notes: [Bis(2-isopropenylphenyl)phenylphosphonio]- bzw. [tert-Butylbis(2-isopropenylphenyl)phos-phonio]methanid (8a und b) lagern sich im Verlauf von 2-3 Tagen zu den isomeren Phosphanen 6,7,8,13-Tetrahdydro-8,13-dimethyl-5-phenyl (bzw. -5-tert-butyl)-8,13-methano-5H-dibenzo[b,e]-phosphonin (13a und b) um. Die Struktur von 13a wurde durch Röntgenstrukturanalyse bewiesen.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 693-702 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Question of Inner Hexacoordination with Pentaarylphosphoranes; Phosphorane Rearrangements at the Level of Coordination Number 5The spirocyclic pentaarylphosphoranes 13 and 18b containing hydroxy groups in the direct neighbourhood of the molecule centre, isomerize more or less readily to the oxyphosphoranes 14 and 22, resp., with retention of coordination number 5. Inner onium-ate complexations could not be detected with the starting materials.
    Notes: Die spirocyclischen Pentaarylphosphorane 13 und 18b, die in unmittelbarer Nachbarschaft zum Molekülzentrum Hydroxylgruppen aufweisen, isomerisieren mehr oder weniger leicht unter Beibehaltung des Koordinationsniveaus 5 zu den Oxyphosphoranen 14 bzw. 22. Innere Onium-At-Komplexierungen konnten bei den Ausgangsverbindungen nicht nachgewiesen werden.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1406-1413 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pentacoordinated Phosphoranes with Azaphosphatriptycene SkeletonMelting of 2,8,15-trimethyl-5,10[1,2]benzenophenophosphazine 4 with o-quinones gave the spirophosphoranes 6-8, which, on account of their rigid tridentate ligand, offered favourable conditions for a novel ground state geometry. However, an X-ray structural analysis of 4′,5′,6′,7′-Tetrachloro-2,8,15-of trimethylspiro[5,10[1,2]benzenophenophosphazine- 10,2′-[1,3,2]benzodioxaphosphole] (6) demonstrated the preeminence of a trigonal bipyramidal structural principle. In solution 6 shows only one 1H NMR signal for its methyl groups, which may be explained by rapid intramolecular positional exchange processes.
    Notes: Zusammenschmelzen von 2,8,15-Trimethyl-5,10[1,2]benzenophenophosphazin 4 mit o-Chinonen lieferte die Spirophosphorane 6-8, die wegen ihres starren dreizähnigen Liganden günstige Voraussetzungen für eine neuartige Grundzustandsgeometrie boten. Die Röntgenstrukturanalyse von 4′,5′,6′,7′-Tetrachlor-2,8,15- trimethylspiro[5,10[1,2]benzenophenophosphazin- 10,2′-[1,3,2]benzodioxaphosphol] (6) beweist jedoch das Vorherrschen eines trigonal-bipyramidalen Bauprinzips. In Lösung zeigt 6 nur ein 1H-NMR-Signal für seine Methylgruppen, was mit raschen intramolekularen Positionenaustausch-Prozessen erklärt werden kann.
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  • 6
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 13 (1974), S. 542-543 
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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  • 8
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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