Group 4 metal bis(chelate) complexes of 2-anilidomethylpyridine ligands: Synthesis and catalytic activity for olefin polymerization

A series of monoanionic, bidentate 2-anilidomethylpyridine ligands were synthesized and used to prepare bis(chelate) Zr(IV) and Hf(IV) bis(dimethylamido) complexes. All complexes were characterized by NMR spectroscopy and elemental analysis. The solution structures of the complexes were more or less fluxional, depending on the substituent on the ligands. The complexes were tested as catalysts for the polymerization of ethylene and propene, in combination with different activators. Use of AliBu2H – methylaluminoxane as the co-catalyst resulted in the generation of catalysts producing high molecular weight polyethylenes with good activities, but yielding only stereoirregular and poorly regioregular polypropylenes.

New 2-anilidomethylpyridine ligands were used to synthesize bis(chelate)zirconium(IV) and hafnium(IV) complexes. All complexes, upon activation with AliBu2H /MAO, resulted in multi-site catalytic systems for the polymerization of ethylene and propene.Figure optionsDownload high-quality image (117 K)Download as PowerPoint slideResearch highlights
► New amidopyridine ligands and their corresponding Zr(IV) and Hf(IV) complexes.
► More or less fluxional solution structure depending on the substituents.
► Multi-site catalytic systems for the polymerization of ethylene and propene.