Titanium and Zirconium Complexes of Robust Salophan Ligands. Coordination Chemistry and Olefin Polymerization Catalysis

摘要

Salans are [ONNO]-type linear tetradentate diamine-diphenolate ligands having an aliphatic bridge between the two amine donors. They tend to wrap around group 4 metals in a fac-fac mode yielding C_2-symmetric octahedral complexes in which the two labile groups are of cis geometry. These features make the Salan complexes suitable for olefin polymerization catalysis and especially for isospecific polymerization (the actual degree of isotacticity is determined by the combined effects of the phenolate ring substit-uents, the size of the metal, and the bulk of the monomer).