Synthesis and structural characterization of an open cage dithiatungstaborane [(CpW)<inf>2</inf>B<inf>4</inf>H<inf>4</inf>S<inf>2</inf>] cluster

Reaction of Cp#MCl4, (1 or 2) [(1): M = Mo, Cp # = Cp* (Cp* = η5-C5Me 5) and (2): M = W, Cp# = Cp (Cp = η5-C 5H5)] with excess of [LiBH4.thf] followed by thermolysis with excess of [HS(CH2)nSH] (n = 2 or 3), leads to the formation of [(Cp*Mo)2B4H 4S2] (3) or [(CpW)2B4H 4S2] (4) respectively. Corresponding to (3) and (4), the compounds [(M)2B5H9] (M = CpW, (5) or Cp*Mo, (6)) are isolated as major product in both the cases. These new compounds have been characterized in solution by mass, 1H, 11B, 13C NMR spectroscopy. The structural types have been unequivocally established by X-ray crystallographic analysis of compounds (4).