Complexes of Amine Phenolate Ligands as Catalysts for Polymerization of α-Olefins

摘要

The coordination chemistry and the catalytic potential in polymerization of alpha-olefins of two families of group IV metal complexes of amine phenolate ligands are outlined. The first family is based on dianionic amine diphenolate ligands. These ligands lead to C_s-symmetrical complexes, in which the two labile groups are in cis geometry. An additional donor on the sidearm was found to be crucial for the activity of the resulting catalysts. Zirconium and hafnium based catalysts led to extremely high activities in polymerization of 1-hexene, whereas titanium catalysts led to living polymerization at room temperature. The second family is based on diamine diphenolate ligands that lead to C_2-symmetrical complexes that may afford isotactic and living polymerization at room temperature, depending on the bulk of the phenolate substituents.