Trinuclear Mixed-valent Gold Complexes Derived from 2-C₆F₄PPh₂: Phosphine Oxide Complexes of Gold(III) and an ortho--Metallated Complex of Gold(I)

Crystals of two mixed-valent gold complexes [(O₂NO)Au^I(μ-2-C₆F₄PPh₂)Au^In {kt²-2-C₆- F₄P(O)Ph₂} (μ-2-C₆F₄PPh₂)Au^I(ONO₂)] (14) and [(O₂NO)Au^I(k²-2-C₆F₄PPh₂)Au^III{k³-2-C₆F₄- P(O)Ph(C6H4)}(μ-2-C₆F₄PPh₂)Au^I] (15) have been obtained from the reaction of the digold(I,III) complex [ClAu^I(μ-2-C₆F₄PPh₂)(K²-2-C₆F₄PPh₂)Au^IIICl] (5) with, respectively, a small and a large excess of silver nitrate. Both complexes contain three, approximately collinear metal atoms, the central gold(III) atom being planar-coordinated by a chelate (0,C)-phosphine oxide formed by oxidation of 2-C₆F₄PPh₂ and the carbon atoms of two bridging 2-C₆F₄PPh₂ groups. In 14 each of the terminal gold(I) atoms is coordinated by a monodentate nitrate ion and the phosphorus atom of μ-2-C₆F₄PPh₂, whereas in 15 the nitrate ion on one of the gold(I) atoms of 14 has been replaced by the carbon atom of a bridging C₆H₄ group derived by Ag+-promoted cyclometallation of a phenyl group on the neighbouring phosphine oxide.