SYNTHESIS OF ETA-CYCLOPENTADIENYL-POLYBORANE DERIVATIVES OF MOLYBDENUM AND TUNGSTEN

The reaction of LiBH4 with [Mo(eta-C5H4Me)Cl4] gives the dimetallaborane bicapped closo-[{Mo(eta-C5H4R)}2B5H9], which has been characterised by X-ray crystallography. The reaction of LiBH4 with [W(eta-C5H4R)Cl4], for R = Me, gives closo-[{W(eta-C5H4Me)H2}2B3H7] or, for R = Pr(i), both closo-[{W(eta-C5H4Pr(i))H2}2B3H7] and nido-[{W(eta-C5H4Pr(i))H3}B4H8]. The reaction between [Mo(eta-C5H4Me)(PMe3)2Cl2] and LiBH4 yields bicapped closo-[{Mo(eta-C5H4Me)}2B5H9] or nido-[{Mo(eta-C5H4Me)(PMe3)H}B4H8], depending on the reaction conditions. Also LiBH4 reacts with [W(PMe3)3Cl4] to give a mixture of nido-[{W(PMe3)2H4}B4H8] and arachno-[{W(PMe3)3H3}B3H8].