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  • 1
    ISSN: 0044-2313
    Keywords: Diphosphane(4) ; Diborane(6) ; Borane-tetrahydrofuran ; Diphosphane-borane ; Diphosphane-1,2-bis(borane) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Phosphorus. 239. On the Reaction of Diphosphane(4) with Diborane(6) and with THF-Borane: Formation of Diphosphane-borane, P2H4 · BH3, and Diphosphane-1,2-bis(borane), BH3 · P2H4 · BH3Diphosphane(4) always reacts with diborane(6) in the temperature range of -118 to -78°C, to furnish a mixture of diphosphane-borane, P2H4 · BH3 (1), and diphosphane-1,2-bis(borane), BH3 · P2H4 · BH3 (2), in addition to small amounts of triphosphane-1,3-bis(borane), BH3 · P3H5 · BH3, and phosphane-borane, BH3 · PH3, irrespective of the molar ratios of the reactants employed. The formation of the 1 : 1 adduct P2H4 · B2H6 reported in the literature [4] could not be confirmed. The structures of compounds 1 and 2 were investigated by nuclear magnetic resonance spectroscopy which revealed the complete, homolytic cleavage of diborane(6). As a result of the bonding of one BH3 group to diphosphane(4), the Lewis basicity of the other PH2 group is markedly reduced. Similar mixtures of products are obtained when the borane adduct THF · BH3 is employed in an analogous reaction. In the case of a 1 : 1 molar ratio of P2H4 : THF · BH3 at -78°C, the reaction furnishes compound 1 exclusively. This product can be isolated in the pure state and is found to be appreciably more stable than diphosphane(4).
    Notes: Diphosphan(4) reagiert mit Diboran(6) im Temperaturbereich von -118 bis -78°C bei unterschiedlichen Reaktandenverhältnissen stets zu einem Gemisch aus Diphosphan-boran, P2H4 · BH3 (1), und Diphosphan-1,2-bis(boran), BH3 · P2H4 · BH3 (2), mit etwas Triphosphan-1,3-bis(boran), BH3 · P3H5 · BH3, und Phosphan-boran, BH3 · PH3. Die Bildung des in der Literatur beschriebenen 1 : 1-Adduktes P2H4 · B2H6 [4] konnte nicht bestätigt werden. Nach kernresonanzspektroskopischen Strukturuntersuchungen der Verbindungen 1 und 2 findet eine vollständige homolytische Spaltung von Diboran(6) statt. Durch die Bindung einer BH3-Gruppe an Diphosphan(4) wird die Lewis-Basizität der anderen PH2-Gruppe deutlich herabgesetzt. Mit dem Boran-Addukt THF · BH3 entstehen ähnliche Produktgemische. Bei Reaktion im Molverhältnis P2H4 : THF · BH3 = 1 : 1 (-78°C) wird ausschließlich Verbindung 1 gebildet, die rein isolierbar und merklich beständiger als Diphosphan(4) ist.
    Additional Material: 4 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 622 (1996), S. 2042-2047 
    ISSN: 0044-2313
    Keywords: Diphosphane-borane ; Triphosphane-2-borane ; Triphosphane-1,3-bis(borane) ; Sodium-1,1,2-tris(borane)-1,2,2-trihydrogendiphosphide ; Diphosphane(4) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Phosphorus. 240. On the Reactive Behaviour of Diphosphane-borane, P2H4 · BH3Under mild temperature conditions, the thermal decomposition of diphosphane-borane (1) gives rise to the formation of phosphane-borane, PH3 · BH3, and triphosphane-2-borane, PH2—PH(BH3)—PH2 (2). In the presence of diphosphane-1,2-bis(borane), triphosphane-1,3-bis(borane), BH3—PH2—PH—PH2—BH3 (3), is formed additionally. The thermolysis product at room temperature is a polymeric solid of varying composition which contains phosphorus, boron, and hydrogen.Compound 1 reacts with metalating agents such as n-BuLi, LiBH4, and NaBH4 to furnish the borane-trihydrogendiphosphide ion, [PH2—PH—BH3]-, which immediately disproportionates to give the corresponding mono-and triphosphane derivatives. In the presence of an excess of THF-borane and in the case of a 1 : 1 molar ratio of 1 : NaBH4, the disproportionation does not occur and the new diphosphide derivative sodium-1,1,2-tris(borane)-1,2,2-trihydrogendiphosphide, Na[(BH3)2PH—PH2BH3] (4) can be obtained. The action of additional NaBH4 yields the diphosphide dianion with four coordinated BH3 groups.
    Notes: Die thermische Zersetzung von Diphosphanboran (1) führt unter milden Temperaturbedingungen zur Bildung von Phosphan-boran, PH3 · BH3, und Triphosphan-2-boran, PH2—PH(BH3)—PH2 (2). In Gegenwart von Diphosphan-1,2-bis(boran) entsteht zusätzlich Triphosphan-1,3-bis-(boran), BH3—PH2—PH—PH2—BH3 (3). Bei Raumtemperatur wird ein polymerer Feststoff gebildet, der Phosphor, Bor und Wasserstoff in wechselnder Zusammensetzung enthält.Die Verbindung 1 reagiert mit Metallierungsmitteln, wie n-BuLi, LiBH4 und NaBH4, zum Boran-trihydrogendiphosphid-Ion, [PH2—PH—BH3]-, das sofort zu entsprechenden Mono- und Triphosphanderivaten disproportioniert. Bei Anwesenheit von überschüssigem THF-Boran und Reaktion im Molverhältnis 1 : NaBH4 = 1 : 1 kann die Disproportionierung verhindert und das neue Diphosphidderivat Natrium-1,1,2-tris-(boran)-1,2,2-trihydrogendiphosphid, Na[(BH3)2PH—PH2BH3] (4), gewonnen werden. Mit weiterem NaBH4 entsteht das Diphosphid-Dianion mit vier koordinierten BH3-Gruppen.
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