Acetonitrile hydration versus molybdenum oxidation at the sulfur-rich bimetallic site {MoIII2Cp2(μ-SMe)3}+. Crystal structure of the μ-η1 ∶ η1-amidato complex [Mo2Cp2(μ-MeCONH)(μ-SMe)3]

The paramagnetic μ-amidato species [Mo2Cp2(μ-MeCONH)(μ-SMe)3]BF42a+ (Cp = η-C5H5) is formed exclusively when the compound [Mo2Cp2(MeCN)2(μ-SMe)3]BF41a in powder form is kept in air, whereas the same starting complex in solution gives a mixture of the μ-amidato species and the μ-oxo complex [Mo2Cp2(μ-O)(μ-SMe)3]BF43. The oxo complex is formed quantitatively on warming [Mo2Cp2(μ-Cl)(μ-SMe)3]BF4 in water. The reduction of 2a+ by NaBH4 in CH3CN affords the molecular product [Mo2Cp2(μ-MeCONH)(μ-SMe)3] 2a which has been characterised by X-ray analysis.