Synthesis and characterization of bis(iminopyrrolyl)zirconium complexes

Diamido and dichloro zirconium complexes having two iminopyrrolyl ligands, Zr(NEt2)(2)(pyr)(2) (2a-e) (pyr = 2-(N-aryliminomethyl)pynolyl) and ZrCl2(pyr)(2) (3a-e), were prepared. The cis-configuration of diamido and dichloro moieties was elucidated on the basis of NMR spectroscopy as well as by a crystallographic study for complex 3a. We demonstrated that these zirconium complexes became catalyst precursors for the polymerization of ethylene in the presence of excess amounts of methylaluminoxane.