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

The synthesis of [ONNO]-type robust Salophan ligands featuring tertiary nitrogen donors is described for the first time. By varying the substitution pattern on the aromatic bridge and on the phenolate rings, four ligands possessing a broad scope of electronic and steric influence were attained. These ligands led to well-defined C₂-symmetric dialkoxo complexes of titanium and zirconium. Dibenzylzirconium complexes of all the Salophan ligands yielded 1-hexene polymerization catalysts following activation with B(C₆F₅)₃, their activity ranging from ultrahigh to low, and polymer microstructure ranging from atactic to isotactic, respectively.