Novel monoanionic di-N,N'-centred chelating ligands and their C1 and C2 symmetrical zirconium complexes

Article abstract of DOI:10.1016/0022-328X(95)06108-9

The novel lithium complexes [Li{N(SiMe₃)C(Ph)C(R)(C₅H₄N-2)}]₂ (R = H or SiMe₃) and Li{N(SiMe₃)C(Ph)C(R)(C₉H₆N-2)} (R = H or SiMe₃), prepared from PhCN and [Li{C(SiMe₃)(R)(C₅H₄N-2)}]₂ or Li{C(SiMe₃)(R)(C₉H₆N-2)}, react with ZrCl₄ to afford racemic complexes [Zr{N(SiMe₃)C(Ph)C(R)(C₅H₄N-2)}₂Cl₂] (R = H or SiMe₃, 3b) and [Zr{N(SiMe₃)C(Ph)C(R)(C₉H₆N-2)}₂Cl₂], respectively. Conproportionation of ZrCl₄ and 3b or 4b afforded [Zr{N(SiMe₃)C(Ph)C(SiMe₃)(C₅H₄N-2)}Cl₃] and [Zr{N(SiMe₃)C(Ph)C(SiMe₃)(C₉H₆N-2)}Cl₃], respectively. The compounds are characterised by NMR spectroscopy and X-ray data are provided for 3b.