Hydride transfer reactions in dimolybdenum compounds: a simple route to the novel mu-eta(1):eta(1)-tetrahydroboride complex [Mo2Cp2(mu-SMe)(3)(mu-BH4)]

The reaction of NaBH4 with the bis-nitrile compound [Mo2Cp2(mu -SMe)(3)(MeCN)(2)](BF4) 1 unexpectedly gives rise to the rare, stable mu-(eta (1)-H):(eta (1)-H) tetrahydroborato complex [Mo2Cp2(mu -SMe)(3)(mu -BH4)] 2, in addition to the expectedazavinylidene product [Mo2Cp2(mu -SMe)(3)(mu-eta (1)-NCHMe)] 3.