Group 4 Metal Complexes Supported by [ONNO]-Type Bis(o-aminophenolato) Ligands: Synthesis, Structure, and α-Olefin Polymerization Activity

摘要: Reaction of 1,4-diazabutanediyl-bridged bis(phenols) [(HOC6H2-4,6-tBu2)2NR(CH2)2NR] (R = H, 1; Me, 2) with the appropriate metal precursors MX4 (M Ti, Zr, Hf; X Cl, OiPr) gave a series group 4 dichloro and di(isopropoxy) complexes [M{2,2′-(OC6H2-4,6-tBu2)2NR(CH2)2NR}X2] M 3; R OiPr, 4; 5; 6; Hf, 7). While for 3, 4, 6, 7 single isomers were observed, titanium complex 5 formed as mixture cis-α (5a) cis-β (5b) isomers. Variable-temperature NMR spectroscopy shows that 3 5b are unstable favor ligand configuration at elevated temperatures, whereas 5a configurationally stable. Complexes 6 show rigid C2-symmetric structures in solution up to 100 °C. Upon activation methylaluminoxane, 3−7 good Ti) excellent Hf) activity polymerization 1-hexene, giving low molecular weight atactic polymers. Styrene is polymerized modest a...