New cage isomers derived from hexaphospha-pentaprismane, P6C4tBu4

UV irradiation of the hexaphospha-pentaprismane cage, P6C4tBu4, causes a structural rearrangement affording two new isomers, one involving a different closed cage structure and the other a more open cage structure containing one PC double bond. The new closed cage isomer was also unexpectedly obtained as the sole product by protonation of P6C4tBu4 with CF3SO3H. Both new P6C4tBu4 isomers were fully characterised by multinuclear NMR spectroscopy and single crystal X-ray diffraction studies.