DICYCLOPENTADIENYL TITANIUM AND ZIRCONIUM COMPLEXES WITH THE DOUBLE BRIDGED BIS(DIMETHYLSILANODIYL) DICYCLOPENTADIENYL [(ME(2)SI)(2)(ETA(5)-C5H3)(2)](2-) LIGAND - X-RAY MOLECULAR-STRUCTURE OF [TI((SIME(2))(2)(ETA(5)-C5H3)(2))ME(2)]

The reaction of the doubly bridged 2,2'-dimethylsilanodiyl)-eta(5)-dic yclopentadienyl titanium and zirconium complexes [M{(SiMe(2))(2)(eta(5 )-C5H3)(2)}Me(2)] (M = Ti (3), Zr (4)) with water gave the mu-oxo deri vatives [{M[(SiMe(2))(2)(eta(5)-C5H3)(2)]Me}(2)(mu-O)] (M = Ti (5), Zr (6)). Addition of one equivalent of M'R (M' = MgCl, R = CH3, CH(2)SiM e(3); M' = Li, R = CH(2)CMe(2)Ph) to toluene or diethyl ether solution s of [M{(SiMe(2))(2)(eta(5)-C5H3)(2)}Cl-2] (M = Ti(1), Zr (2)) afforde d the chloro alkyl derivatives [M{(SiMe(2))(2)(eta(5)- C5H3)(2)}ClR] ( M = Ti, R = CH(2)SiMe(3) (8); M = Zr, R = Me (7), CH(2)CMe(2)Ph (9)). Compounds 3 and 4 reacted with [CPh(3)][B(C6F5)(4)] at -78 degrees C i n CD2Cl2 leading to the cationic species [{M[(SiMe(2))(2)(eta(5)-C5H3) (2)]Me}(2)(mu-Me)](+) (M = Ti (10), Zr (11)) as demonstrated by NMR sp ectroscopy. The titanium(III) and zirconium(III) derivatives [M{(SiMe( 2))(2)(eta(5)-C5H3)(2)}(mu-Cl)](2) (M = Ti (12), Zr (13)) were obtaine d by reduction of 1 and 2 with one equivalent of sodium amalgam. The X -ray molecular structure of [Ti{(SiMe(2))(2)(eta(5)-C5H3)(2)}Me(2)] (3 ) has been determined by diffraction methods.