Synthesis and characterisation of enantiomerically-pure zirconium complexes containing a linked amido-cyclopentadienyl ligand;: X-ray structures of [Zr{η5:η1-C5Me4SiMe2NCH(Me)(Ph)}X2] (X = NMe2 and Cl) and [Zr{η5:η1-C5Me4SiMe2NCH(Me)(Ph)}-Cl(μ-Cl)]2

Enantiomerically-pure zirconium amido-cyclopentadienyl complexes [Zr{eta(5):eta(1)-C5Me4SiMe2NCH(Me)(Ph)}(NMe2)(2)] (R-1 and S-1) have been prepared by the reaction of Zr(NMe2)(4) with [HC5Me4SiMe2NHCH(Me)(Ph)] (HCp*NH). Subsequent aminolysis of R-1 or S-1 with Me3SiCl gave the dimeric chloro-bridged zirconium complex [Zr{eta(5):eta(1)-C5Me4SiMe2NCH(Me)(Ph)}Cl(mu-Cl)](2) (RR-2 and SS-2) which upon sublimation under vacuum yielded the monomeric compound R- and S-[Zr{eta(5):eta(1)-C5Me4SiMe2NCH(Me)(Ph)}Cl-2] (R-3 and S-3), respectively. Alternatively, the metathesis reaction of the dilithium salt (Cp*N)Li-2 with ZrCl4(THF)(2) afforded RR/SS-2 in relatively low yields. Compounds 1-3 have been characterised in solution by NMR spectroscopy. The molecular structures of R-I, S-l, RR-2 and S-3 have been determined by X-ray crystallography. The Zr-N(appended amido) bond distances and Cp*(centroid)-M-N bond angles in R-1, S-1, RR-2 and S-3 are 2.098(2), 2.108(3), 2.052(av), 2.014(2) Angstrom and 110.5, 100.7, 100.6(av), 101.0 degrees, respectively. (C) 1999 Elsevier Science S.A. All rights reserved.