Synthesis and structure of P-7[Si(SiMe3)(3)](3) (tri(hypersilyl)heptaphosphanortricyclane)

By reaction of sodium-potassium phosphide (prepared from white or red phosp horus and sodium-potassium alloy) and chlorotris(trimethylsilyl)silane, P-7 [Si(SiMe3)(3)](3) has been prepared in high yields. An X-ray analysis prove d that the molecule is composed of a P-7-nortricyclane cage substituted wit h three Si(SiMe3)(3) groups and that two enantiomers are present in crystal s grown from benzene. The P-31 NMR spectrum shows the complex splitting pat tern of an A[MX](3) spin system. P-31 chemical shifts and P-31, P-31 one-bo nd and two-bond coupling constants have been calculated by numerical simula tion of the spectrum.