New Group 4 Transition Metal Complex Catalysts for Living Olefin Polymerization

摘要

Recently, we have discovered new series of group 4 transition metal complexes, FI Catalysts having two phenoxy-imine bidentate ligands, and PI Catalysts having pyrrolide-imine bidentate ligands. FI Catalysts with fluorinated aniline moieties, using MAO as a cocatalyst, turn out to be highly active living polymerization catalysts at or over room temperature. One of these Fl Catalysts possessing o-SiMe_3 group to the phenoxy oxygen produced extremely high syndiospecific ([rr]: 94 percent, Tm : 156 deg C) and monodisperse (Mw/M~: 1.08) polypropylene at 0 C. Stereochemistry of propylene monomer enchainment is operated through chain-end control and the ortho-substituent exhibits dramatic effect on syndiospecificity (ligand-directed chain-end control). Many block copolymers (syn-PP-b-EPR, PE-b-EPR, PE-b-syn-PP, PE-b-EPR-b-syn-PP, PE-b-EPR-b-PE) can be synthesized with those FI Catalysts by sequential monomer addition. Alternatively, PI Catalysts promoted living ethylene/norbornene copolymerization at 25 deg C and produced high molecular weight (>800,000) ethylene/norbornene monodisperse copolymer with highly alternating character.