Tuning the reactivity of N,O,O,O-non-metallocene catalysts for α-olefin polymerization: Issues related to ligand symmetry and derivatization

Titanium-based precatalysts, bearing C3 or pseudo-Cs symmetric aminotriol ligands, upon activation with methylaluminoxane, polymerize hex-1-ene to give polymers of high molecular weight, i.e., 50 000 and 600 000, respectively, with low dispersity, 1.2-1.4, and high isotacticity, 85-60%, depending on the overall symmetry of the precatalysts, but when one arm of the aminotriol ligands is methylated to yield C2 or meso aminodiol ligands, their corresponding titanium catalysts gave higher-molecular-weight polyhexenes, 300 000 to 250 000, with lower dispersities, 1.07-1.11, which possibly suggests living polymerization, with activities 200-500 times greater than that of the parent C3 and pseudo-Cs catalysts. © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.