Acetonitrile hydration versus molybdenum oxidation at the sulfur-rich bimetallic site {(Mo2Cp2)-Cp-III(mu-SMe)(3)}(+). Crystal structure of the mu-eta(1):eta(1)-amidato complex [Mo2Cp2(mu-MeCONH)(mu-SMe)(3)]

The paramagnetic mu -amidato species [Mo2Cp2(mu -MeCONH)(mu -SMe)(3)]BF4 2a(+) (Cp=eta -C5H5) is formed exclusively when the compound [Mo2Cp2(MeCN)(2)(mu -SMe)(3)]BF4 1a in powder form is kept in air, whereas the same starting complex in solution gives a mixture of the mu -amidato species and the mu -oxo complex [Mo2Cp2(mu -O)(mu -SMe)(3)]BF4 3. The oxo complex is formed quantitatively on warming [Mo2Cp2(mu -Cl)(mu -SMe)(3)]BF4 in water. The reduction of 2a(+) by NaBH4 in CH3CN affords the molecular product [Mo2Cp2(mu -MeCONH)(mu -SMe)(3)] 2a which has been characterised by X-ray analysis.