Synthesis of Titanium Complexes Containing an Amine Triphenolate Ligand of the Type [TiX{(O-2,4‑R2C6H2)‑6-CH2}3N] and the Ti–Al Heterobimetallic Complexes with AlMe3: Effect of a Terminal Donor Ligand in Ethylene Polymerization

The synthesis of various titanatranes containing tris­(aryloxo)­amine ligands, TiX­[{(O-2,4-R2C6H2)-6-CH2}3N] [R = Me (1), tBu (2); X = OiPr (a), OtBu (b), OCH­(CF3)2 (c), OC­(CF3)3 (d), Cl (e)], and some reactions with Al alkyls have been explored. The Ti–Al heterobimetallic complexes [TiMe­{(O-2,4-Me2C6H2-6-CH2)2­(μ2-O-2,4-Me2-C6H2-6-CH2)}­N]-[Me2Al­(μ2-OR′)] [R′ = tBu (3b), CH­(CF3)2 (3c), C­(CF3)3 (3d)] were isolated by reaction of 1bd with 1 equiv of AlMe3, whereas reaction of 2b with AlMe3 in toluene did not take place under the same conditions, and the reaction of 2c afforded the methyl complex TiMe­[{(O-2,4-tBu2C6H2)-6-CH2}3N]. Structures of 3b,c were determined by X-ray crystallography. These complexes exhibited high catalytic activities for ethylene polymerization in n-octane in the presence of MAO, and the activity by 1 and 2 was affected by the terminal donor ligand (X) as well as the substituent on the atrane ligand (R). The activities by 1c,d increased upon addition of AlMe3, and the corresponding heterobimetallic complexes (3c,d) showed high activities, whereas an increase in the activity upon addition of AlMe3 was not observed by 1b,e, and 2c,e.