(Triphenylphosphane)gold(I) scrambling in a hexanuclear complex of phenylene-1,2-bis(phosphane)

Phenylene-1,2-bis (phosphane) reacts with two mole-equivalents of tris[(triphenylphosphane)gold(I)]oxonium tetrafluoroborate in dichloromethane at -78 degrees C to give high yields of a hexanuclear complex [C6H4[P(AUPPh(3))(3)](2)](2+) . 2 BF4- (1). The variable-temperature P-31(H-1)-NMR spectra of the product in CD2Cl2 at -80 degrees C are compatible with a static structure featuring three Ph(3)PAu units associated with each of the two C6H4P2 phosphide functions, as derived from a clear doublet/quartet pattern. At 50 degrees C in CDCl3, however, there is rapid intramolecular scrambling of these Ph(3)PAu units, which gives rise to a triplet/septet pattern with the J(P,P) value reduced to exactly one half of the value at the low-temperature limit.