Titanium Complexes Bearing NNO‐Tridentate Ligands: Highly Active Olefin Polymerization Catalysts with Great Control on Molecular Weight and Distribution†

Comprehensive Summary A series of titanium amido complexes ( 1‐Ti(NMe 2 ) 2 to 4‐Ti(NMe 2 ) 2 ) bearing NNO‐tridentate ligands was synthesized from the reactions of phenoxy‐imine‐amine ligands with one equivalent of Ti(NMe 2 ) 4 . Subsequently, titanium dichloride complexes ( 1‐TiCl 2 to 4‐TiCl 2 ) were prepared by treatment of titanium amido complexes with excess Me 3 SiCl in toluene. All metal complexes were characterized by 1 H and 13 C NMR spectroscopy, and the molecular structures of complexes of 2‐Ti(NMe 2 ) 2 , 2‐TiCl 2 , and 4‐TiCl 2 in the solid state were determined by single‐crystal X‐ray diffraction. Upon activation with MAO, titanium dichloride complexes as single‐site catalysts were extremely active toward ethylene homopolymerization with great control on molecular weight and distribution. In particular, 3 ‐ TiCl 2 /MAO exhibited an activity as high as 1.35 × 10 8 g(PE)·mol −1 (Ti)·h −1 at 70°C and produced polyethylene with high molecular weight (41.7 × 10 4 g∙mol −1 ) and very narrow distribution ( Đ = 1.23). In the presence of 1‐octene as comonomer, linear low‐density polyethylenes (LLDPEs) with ultrahigh molecular weights ( M w = 136—326 × 10 4 g∙mol −1 ) and narrow distributions ( Đ = 1.20—1.50) were successfully synthesized.