New phenoxyketimine titanium complexes: combining isotacticity and living behavior in propylene polymerization.

A series of titanium bis(phenoxyketimine) olefin polymerization catalysts were synthesized and screened for propylene polymerization. The phenoxyketimine ligands contain pentafluorophenyl N-aryl groups and ortho-phenol substituents of varying size. Catalysts with ortho-phenol substituents of intermediate size produce living, substantially isotactic polypropylene. The living nature of these catalyst systems is demonstrated through the synthesis of block copolymers with narrow molecular weight distributions.