Binuclear zirconium complexes with bidentate N-(ortho-dimethylaminobenzyl)anilide ligands: Synthesis, characterization, and catalytic properties for ethylene polymerization and copolymerization with 1-hexene

Abstract

A series of binuclear zirconium complexes of the type [ortho-(Me2N)C6H4CH2NArZrCl2(μ-Cl)]2 [Ar=2,6-Me2C6H3 (1), 2,6-Et2C6H3 (2), 2,6-iPr2C6H3 (3)] were synthesized by reactions of ZrCl4 with corresponding ortho-(Me2N)C6H4CH2NArLi. All new zirconium complexes were characterized by 1H and 13C NMR spectroscopy and elemental analyses. The molecular structures of complexes 1 and 2 were determined by single crystal X-ray diffraction analysis. Upon activation with AliBu3 and Ph3CB(C6F5)4, complexes 1–3 exhibit moderate catalytic activity for ethylene polymerization and copolymerization with 1-hexene, producing high or ultra high molecular weight polyethylene or relatively high molecular weight poly(ethylene-co-1-hexene) with reasonable 1-hexene incorporation.