Effect of distal metal species on lewis basicity of a μ 3 -oxo ligand in a doubly oxo-bridged (μ 3 -O)[Rh(cod)] 3 (μ 4 -O)M core.

The Lewis basicity of a μ 3 -oxo ligand for (μ 3 -O)[Rh(cod)] 3 (μ 4 -O)M (cod = 1,5-cyclooctadiene) complexes was controllable by metal species on the μ 4 -oxo ligand locating at the opposite site of the μ 3 -oxo ligand. Coordination of the μ 3 -oxo ligand of [(μ 3 -O){Rh(cod)} 3 (μ 4 -O){Au(PPh 3 )}][BF 4 ] (1) to [Au(PPh 3 )] + indicated sufficient Lewis basicity of the μ 3 -oxo ligand in 1 to form [{(Ph 3 P)Au}(μ 3 -O){Rh(cod)} 3 (μ 4 -O){Au(PPh 3 )}][BF 4 ] (2). In contrast, the addition of Li + to 1 induced elimination of the originally coordinated [Au(PPh 3 )] + due to the weak Lewis basicity of the μ 3 -oxo ligand for (μ 3 -O){Rh(cod)} 3 (μ 4 -O)Li(THF) 3 , in which a pentanuclear species, [{(Ph 3 P)Au}(μ 3 -O){Rh(cod)} 3 (μ 4 -O){Li(THF) 3 }][BF 4 ] (3), was assumed to be generated in situ before the dissociation of [Au(PPh 3 )] + .