Coordination and Reactivity Study of Titanium and Zirconium Complexes of the First Imidazol-2-imine Ethenolate Ligand

The synthesis and structural characterization of group 4 transition metal complexes bearing a novel imidazol-2-imine enolate ligand with different electronic properties are reported. X-ray crystallographic studies of a cyclopentadienyl zirconium complex confirmed the coordination motif of the ligand through the imine nitrogen and ethenolate oxygen atoms, yielding a new class of formally four-electron-donor monoanionic bidentate ligands. The activities of the corresponding titanium­(IV) and zirconium­(IV) complexes in ethylene polymerization were assessed, resulting in activities up to 170 kg PE mol–1 h–1.