The synthesis of the substituted silyl cyclopentadiene ligand [C5H5-Si
(CH3)(2)(p-C6H4Br)] ((CpH)-H-Si) (1) is described. Deprotonation of (i
) gives ((CpLi)-Li-Si) (2) which reacts with 1/2 ZrCl4 to produce the
bent, sandwich complex Zr(Cp-Si)(2)Cl-2 (3). Compound (3) can be alkyl
ated to give Zr(Cp-Si)(2)(CH3)(2) (4). Reaction of CpZrCl3 .(Et2O)(1/
2) with (2) in ether produces (3) and Zr(Cp-Si)(C5Me5)Cl-2 (5) as the
minor and major products, respectively, whereas reaction in toluene pr
oduces only 5. Et2O and THF are found to catalyze the observed ring lo
ss during the synthesis of 5. Alkylation of 5 produces Zr(Cp-Si)(C5Me5
)(CH3)(2) (6). (C) 1998 Elsevier Science S.A. All rights reserved.