Catalytic Activities for Olefin Polymerization: Titanium(III), Titanium(IV), Zirconium(IV), and Hafnium(IV) β-Diketiminato, 1-Aza-1,3-butadienyl–Imido, and 1-Aza-2-butenyl–Imido Complexes Bearing an Extremely Bulky Substituent, the Tbt Group (Tbt = 2,4,6-[(Me₃Si)₂CH]₃C₆H₂)

Abstract

β-Diketiminato and 1-aza-1,3-butadienyl–imido complexes [MCl3{TbtNC(Me)CHC(Me)NMes}(thf)n] (1a, 1b, 1c) and [M(═NTbt)Cl2{C(Me)CHC(Me)NMes}Li(tmeda)] (3a, 3b, 3c) (M = Ti, Zr, Hf) bearing an extremely bulky substituent, Tbt group (Tbt = 2,4,6-[(Me3Si)2CH]3C6H2) showed high activities for ethylene polymerization and ethylene/1-hexene copolymerization (up to 1.1 × 107 g of polymer·mol M–1 h–1). Complexes 1a, 1b, 3a, 3b, and 3c could produce ultrahigh molecular weight ethylene/1-hexene copolymers (Mw > 4 × 106) that were hardly soluble in o-dichlorobenzene under the molecular weight measurement conditions.