Group 4 permethylindenyl constrained geometry complexes for ethylene polymerisation catalysis

We report the synthesis and characterisation of six permethylindenyl constrained geometry complexes of the type (2SB)-S-Me(N-R,I*)TiCl2 ({((5)-C9Me6)Me2Si(N-R)}TiCl2; R = i-Pr, t-Bu, n-Bu, Ph, 4-t-BuPh and 4-n-BuPh). Three complexes (R = i-Pr, t-Bu and 4-t-BuPh) have been structurally characterised using single crystal X-ray diffraction. Reaction with solid polymethylaluminoxane (sMAO) yields solid catalysts active for the slurry phase polymerisation of ethylene. The activities increase with increasing electron donating character of the amido fragment. (2SB)-S-Me(Nt-Bu,I*)TiCl2 exhibits an activity of 3602 kg(PE) mol(Ti)(-1) h(-1) bar(-1) (30 minutes, 2 bar ethylene), an activity significantly greater than the previously synthesised (2SB)-S-Me(Nt-Bu,Cp*)TiCl2.