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  • 1
    ISSN: 0044-2313
    Keywords: 1,2-Bis(dimethylamino)-3,4,5-triphenyl-3,4,5-triphospha-1,2-diborolane ; 1,2-bis(dimethylamino)-3,4,5,6-tetra-tbutyl-3,4,5,6-tetraphospha-1,2-diborine ; preparation ; NMR ; molecular structures ; ab initio calculations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,2-Bis(dimethylamino)-3,4,5-triphenyl-3,4,5-triphospha-1,2-diborolane and 1,2-Bis(dimethylamino)-3,4,5,6-tetra-tbutyl-3,4,5,6-tetraphospha-1,2-diborine: Synthesis and Structure as well as Calculations on the Molecular StructureThe diphosphides K2[(C6H5)P—(C6H5)P—P(C6H5)], 4 or K2[(tBuP)—(tBuP)2—P(tBu)], 5, react with (ClBNMe2)2 to form the binary 5-membered ring system 1,2-bis(dimethylamino)-3,4,5-triphenyl-3,4,5-triphospha-1,2-diborolane (C6H5P)3(BNMe2)2, 2a, and the 6-membered ring system 1,2-bis(dimethylamino)-3,4,5,6-tetra-tbutyl-3,4,5,6-tetraphospha-1,2-diborine, (tBuP)4(BNMe2)2, 3a, respectively. 2a and 3a could be obtained in a pure form and characterized NMR spectroscopically and by X-ray structure analyses. The two ring systems are folded; 2a exists in the „envelope“- 3a in the „boat“-conformation. Ab initio computations for 3,4,5-triphospha-1,2-diborolane M5 show that the global minimum is characterized by one B—P double bond. The parent compound geometry M6 is characterized by transannular bonding in the PH—BH—BH—PH moiety which differs in character from those in the four- and five-membered rings (BH)2(PH)2 and (BH)2(PH)3 M5 d, respectively. Explicit calculation of the influence of amino substituents on boron improved agreement of the bond length between computed and X-ray data.
    Notes: Die Diphosphide K2[(C6H5)P—(C6H5)P—P (C6H5)], 4, bzw. K2[(tBuP)—(tBuP)2—P(tBu)], 5, reagieren mit (ClBNMe2)2 zu dem binären Fünfringsystem 1,2-Bis(dimethylamino)-3,4,5-triphenyl-3,4,5-triphospha-1,2-diborolan (C6H5P)3(BNMe2)2, 2a, bzw. dem Sechsringsystem 1,2-Bis(dimethylamino)-3,4,5,6-tetra-tbutyl-3,4,5,6-tetraphospha-1,2-diborin, (tBuP)4(BNMe2)2, 3a. 2a und 3a konnten in reiner Form isoliert, NMR-spektroskopisch und durch Röntgenstrukturanalysen charakterisiert werden. Beide Ringsysteme sind gefaltet; 2a zeigt eine „envelope“- 3a eine „Wannen“-Konformation.Ab initio Berechnungen an 3,4,5-Triphospha-1,2-diborolan M5 zeigen, daß im globalen Minimum eine B—P-Doppelbindung mit annähernd planarem σ3-Phosphor vorliegt. Die Geometrie der Stammverbindung des Sechsringes M6 weist „durch-den-Ring“-Bindung in der PH—BH—BH—PH-Baugruppe auf, welche sich von jenen im Vier- und Fünfring M5 d unterscheidet. Durch die explizite Berechnung des Einflusses von Aminosubstituenten an Bor auf die Geometrien des Fünf- und Sechsringes verbessert sich die Übereinstimmung der Bindungslängen mit den Daten der Röntgenstrukturanalyse.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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