HYPER-COORDINATE PHOSPHORUS ATOMS IN A GOLDEN HOUR-GLASS

Treatment of phosphine, PH3, or bis(pivaloyl)phosphine, ((t)BuCO)(2)PH , with (triphenylphosphine)gold]oxonium}tetrafluoroborate (Ph(3)PAuOBF4 in tetrahydrofuran at -60 degrees C affords small amounts of a tri cationic nona-nuclear gold complex {Au[P(AuPPh(3))(4)](2)}(3+)(BF4-)(3 ). The low temperature {H-1} P-31 NMR spectra of this product exhibit an (A(4)M)(2) spin system indicating0 a highly symmetrical species of D-4d or D-4h symmetry in solution. The D-4h structure, resembling a go lden hour-glass, has been confirmed by an X-ray diffraction analysis o f single crystals (tetragonal space group I4/mmm, Z = 2, a = 16.878(2) , c = 30.320(3) Angstrom). The trication contains two square pyramidal P(AuPPh(3))(4)(+) units P-coordinated to the central Au+ cation.