A tetracyclic Octaphosphane R2P8 via Addition, Inversion and Condensation

The first isolated example of an octaphosphane of type R2P8 is obtained by treatment of cage compound (DDP)GaP4 (DDP = (2,6-diisopropylphenyl)(4-((2,6-di­iso­propyl­phenyl)imino)pent-2-en-2-yl)amide)[1] with (C6F5)2PBr. The... [ view full abstract ]

The first isolated example of an octaphosphane of type R₂P₈ is obtained by treatment of cage compound (DDP)GaP₄ (DDP = (2,6-diisopropylphenyl)(4-((2,6-di­iso­propyl­phenyl)imino)pent-2-en-2-yl)amide)^[1] with (C₆F₅)₂PBr. The initially formed endo-exo butterfly shaped pentaphosphane rapidly rearranges to the more stable exo-exo isomer 1 which undergoes dimerization to decaphosphane 2.^[2] Compound 2 unexpectedly eliminates tetraaryldiphosphane (R₄P₂) to give tetracyclo‌[3.3.0.0^2,7.0^4,6]‌octaphosphane [(DDP)GaBr]₂P₈ (3). The reaction steps were proven by crystal structure analysis of the key intermediates and supported by kinetic studies using NMR techniques.

Acknowledgements

The authors thanks the Deutsche Forschungsgemeinschaft for funding (DFG WE 4621/3-1). F. H. thanks the Fonds der Chemischen Industrie and the Studienstiftung des Deutschen Volkes for doctoral fellowships.

References

[1] G. Prabusankar, A. Doddi, C. Gemel, M. Winter, R. A. Fischer, Inorg. Chem. 2010, 49, 7976-7980.

[2] M. H. Holthausen, J. J. Weigand, Chem. Soc. Rev. 2014, 43, 6639-6657.