Cationic Carboxylato Complexes of Dirhodium(II) with Oxo Thioethers: Promising Catalysts with Unusual Coordination Modes

Removal of an acetato ligand from dirhodium(II) acetato complexes with thioethers of the
general structure [Rh2(μ-OAc)4(RSCH2Z)2] yields the cationic complexes [Rh2(μ-OAc)3(RSCH2Z)2](BF4) (R = Me, Ph; Z = C(O)OEt, CH2C(O)OMe). The methylthio complex with
Z = C(O)OEt has been structurally characterized and found to exhibit an unusual bidentate
O−S coordination of the oxo thioether ligands. Preliminary tests indicate that the complex
is a promising catalyst of the silylformylation or hydrosilylation of 1-hexyne with dimethylphenylsilane.