Molybdocenes and tungstenocenes derived from molybdenum(IV) and tungsten(IV) dihydride

Recent results of our studies on preparation of group 6 (Mo, W) metallocenes are reviewed. Molybdenum(IV) and tungsten(IV) dihydride Cp2MH2 (M = Mo, W; Cp = η-C5H5) have primarily been used as starting materials. Protonation with p-toluenesulfonic acid (TsOH) opens up a convenient route to the preparation of monohydridotosylato complexes Cp2MH(OTs), which hold potential as precursors for more sophisticated molybdocene or tungstenocene derivatives. Promising synthetic applications of them are also described.