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-[(Me _3Si) _2CH] _3C _6H _2)

摘要

β-Diketiminato and 1-aza-1,3-butadienyl-imido complexes [MCl _3{TbtNC(Me)CHC(Me)NMes}(thf) _n] (1a, 1b, 1c) and [M(= NTbt)Cl _2{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-[(Me _3Si) _2CH] _3C _6H _2) showed high activities for ethylene polymerization and ethylene/1-hexene copolymerization (up to 1.1 × 10 _7 g of polymer·mol M ~(-1) h ~(-1)). Complexes 1a, 1b, 3a, 3b, and 3c could produce ultrahigh molecular weight ethylene/1-hexene copolymers (M _w > 4 × 10 ~6) that were hardly soluble in o-dichlorobenzene under the molecular weight measurement conditions.