Monocyclopentadienyl phenoxy-imine and phenoxy-amine complexes of titanium and zirconium and their application as catalysts for 1-alkene polymerisation

Deprotonation of the phenol-imines 2-Bu^t-6-(RNCH)C₆H₃OH (R=2,4,6-Me₃C₆H₂ (1a), C₆F₅ (1b), C₆H₁₁ (1c) and phenol-amines 2,4-Bu^t₂-6-(R'NCH₂)C₆H₂OH (R'=C₄H₈ (1d), C₅H₁₀ (1e)) with n-BuLi gives the corresponding lithium phenoxides. The reaction with MCl₄ in THF solution leads to the bis(ligand) complexes {2-Bu^t-6-(RNCH)C₆H₃O}₂MCl₂ and {2,4-Bu^t₂-6-(R'NCH₂)C₆H₂O}₂MCl₂ (M=Ti: 2a, 2d, 2e, Zr: 3a, 3d and 3e). The cyclopentadienyl phenoxy-imine and -amine complexes Cp{2-Bu^t-6-(RNCH)C₆H₃O}MCl₂ and Cp{2,4-Bu^t₂-6-(R'NCH₂)C₆H₂O}MCl₂ (M=Ti: 4a–4e, Zr: 5a–5e) were prepared similarly through reaction with CpMCl₃. The crystal and molecular structures of 2a, 3a, 4a and 4e have been determined. 2a and 3a are isostructural and exhibit a distorted octahedral geometry. 4a has a distorted square-pyramidal structure whereas 4e is essentially tetrahedral and the nitrogen does not coordinate. All new complexes are active for the polymerisation of ethene when activated with methyaluminoxane. 4b, 5a, 5d and 5e are active for the copolymerisation of ethene and 1-hexene and the oligomerisation of 1-hexene.