Reduction of [Cp2∗Mo2O5] by mercaptopropionic acid in an aqueous medium. Isolation and characterization of a dinuclear oxo- and 3-sulfido-proprionato(2-)-bridged molybdenum(IV) compound

Reaction of Cp2∗Mo2O5 with HSCH2CH2COOH in acidic (by CF3COOH) 50:50 MeOH–H2O solvent at room temperature yields compound Cp2∗Mo2(μ-O)(μ-SCH2CH2CO2)2, a dinuclear diamagnetic MoIV compound with a two-leg-sharing bis(four-legged piano stool) structure and a Mo–Mo distance of 2.6833(6) Å. A reaction monitoring by ESI MS shows the formation of an intermediate 18 mass units heavier, interpreted as a dihydroxo analogue. Electrochemistry shows a reversible, pH independent oxidation process and an irreversible, pH-dependent reduction process. Contrary to a recently published analogous reaction with the closely related HSCH2COOH substrate, this process does not lead to C–S bond cleavage.

Graphical abstractCompound HSCH2CH2COOH reduces and coordinates molybdenum upon interaction with Cp2∗Mo2O5, to yield Cp2∗Mo2(μ-O)(μ-SCH2CH2CO2)2 but, unlike the closely related HSCH2COOH substrate, does not lead to C–S bond cleavage.Figure optionsDownload full-size imageDownload as PowerPoint slide