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-But-6-(RNCH)C6H3OH (R=2,4,6-Me3C6H2 (1a), C6F5 (1b), C6H11 (1c) and phenol-amines 2,4-But2-6-(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-But-6-(RNCH)C6H3O}2MCl2 and {2,4-But2-6-(R′NCH2)C6H2O}2MCl2 (M=Ti: 2a, 2d, 2e, Zr: 3a, 3d and 3e). The cyclopentadienyl phenoxy-imine and -amine complexes Cp{2-But-6-(RNCH)C6H3O}MCl2 and Cp{2,4-But2-6-(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.