1,2-Bis(dimethylamino)-3,4,5-triphenyl-3,4,5-triphospha-1,2-diborolan und 1,2-Bis(dimethylamino)-3,4,5,6-tetra-tbutyl-3,4,5,6-tetraphospha-1,2-diborin: Synthese und Struktur sowie Berechnungen zur Molekülstruktur |
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| Authors: | B Riegel H-D Hausen W Schwarz G Heckmann H Binder E Fluck A Dransfeld P V R Schleyer |
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| Abstract: | 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 Structure The 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. |
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| 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 |
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