Effect of distal metal species on lewis basicity of a µ3-oxo ligand in a doubly oxo-bridged (µ3-O)[Rh(cod)]3(µ4-O)M core.

ABSTRACT

The Lewis basicity of a µ3-oxo ligand for (µ3-O)[Rh(cod)]3(µ4-O)M (cod = 1,5-cyclooctadiene) complexes was controllable by metal species on the µ4-oxo ligand locating at the opposite site of the µ3-oxo ligand. Coordination of the µ3-oxo ligand of [(µ3-O){Rh(cod)}3(µ4-O){Au(PPh3)}][BF4] (1) to [Au(PPh3)]+ indicated sufficient Lewis basicity of the µ3-oxo ligand in 1 to form [{(Ph3P)Au}(µ3-O){Rh(cod)}3(µ4-O){Au(PPh3)}][BF4] (2). In contrast, the addition of Li+ to 1 induced elimination of the originally coordinated [Au(PPh3)]+ due to the weak Lewis basicity of the µ3-oxo ligand for (µ3-O){Rh(cod)}3(µ4-O)Li(THF)3, in which a pentanuclear species, [{(Ph3P)Au}(µ3-O){Rh(cod)}3(µ4-O){Li(THF)3}][BF4] (3), was assumed to be generated in situ before the dissociation of [Au(PPh3)]+.