Synthesis of half-titanocenes containing 1,3-imidazolidin-2-iminato ligands of type, Cp*TiCl2[1,3-R2(CH2N)2CN]: highly active catalyst precursors in ethylene (co)polymerisation

Abstract

A series of (pentamethylcyclopentadienyl)titanium(IV) dichloride complexes containing 1,3-imidazolidin-2-iminato ligands of type, Cp*TiCl₂[1,3-R₂(CH₂N)₂CN] [R = ^tBu (1a), cyclohexyl (Cy, 1b), C₆H₅ (1c), 2,6-Me₂C₆H₃ (1d), 2,6-ⁱPr₂C₆H₃ (1e)] have been prepared and structures of 1b–e have been determined by X-ray crystallography. These complexes, especially 1d,e showed notable catalytic activities not only for ethylene polymerisation, but also for ethylene/1-hexene copolymerisation (activity 482 000–1 750 000 kg-polymer per mol-Ti per h) in the presence of MAO.