Gold(III) derivatives with anionic oxygen ligands: mononuclear hydroxo, alkoxo and acetato complexes. Crystal structure of [Au(bpy)(OMe)(2)][PF6]

A variety of gold(III) adducts having sigma-ligated oxygen-donor ligands have been prepared from [Au(bpy)Cl-2][PF6] 1 (bpy = 2,2'-bipyridine) either by partial or total replacement of the chloride ions. The new species comprise hydroxo, [Au(bpy)(OH)Cl][PF6] 2 and [Au(bpy)(OH)(2)][PF6] 3, oxo, [Au-2(bpy)(2)(mu-O)(2)][PF6](2) 4, acetato, [Au(bpy)(O2CMe)(2)][PF6] 5, and alkoxo complexes, [Au(bpy)(OR)Cl][PF6] 6, 7 and [Au(bpy)(OR)(2)][PF6] 8-10 (R = Me 6 and 8; Et 7 and 9; Pr-i 10). The dihydroxo and the oxo complexes can be interconverted by refluxing the former in anhydrous THF and the latter in water. The hydroxides 2 and 3 and the acetato complex 5 undergo sigma-ligand metathesis in ROH solution (R = Me, Et or Pr-i) to give the corresponding alkoxides. The crystal structure of 8, the first of a gold(III) methoxo complex, has been determined by X-ray diffraction analysis.