Flavone complexes of Ti and Zr active in ethylene polymerization

Abstract

Two new complexes of Ti and Zr were synthesized with 3-hydroxyflavone bidentate ligand and investi-gated in homogeneous ethylene polymerization. Both complexes were characterized by UV–VIS,1H and13C NMR, and electrochemical studies. The geometries and energies of all possible isomeric species werestudied by full unconstrained optimizations performed at Density Functional Theory (DFT) level. Thepolymerization reactions were performed at different experimental conditions with methylaluminox-ane (MAO), as the cocatalyst. Both complexes were active in ethylene polymerization in all the conditionsused. However, zirconium complex showed the best activity comparing to the titanium complex at 2500Al/M ratio. The polymers obtained were high density polyethylene with ultra high molecular weights.