Amine-Phenolate Titanium and Zirconium Catalysts

Additionally, complexes 37a,b employing 3,5-difluorophenyl /V-aryl groups and substituents 

Utilizing a related complex, Coates and coworkers reported that 30b/MAO at 50 °C polymerized ethylene to produce polyethylene with MJM = 1.10 and M = 44 500 g/mol (Reinartz et al, 2003). Additionally, Ivanchev et al reported a near-linear increase in M with time for the polymerization of ethylene with 30a/MAO at 30 °C (Ivanchev et al, 2004). In later work on the same system, Fujita and coworkers found that molecular-weight distributions were low at a reaction time of one minute M /M = 1.12, = 52 000 g/mol) while the PDl 

Bis(phenoxyimine) titanium complexes have also been employed in the living copolymerization of ethylene/cyclic olefins and ethylene/l,5-hexadiene. Utilizing 31/MAO and varying ethylene pressure, a series of poly(E-co-CP)s with different cyclopentene contents were prepared (Fujita and Coates, 2002). When ethylene pressure was low ( 1 psi), an almost perfectly alternating copolymer was formed (Mn = 21000 g/mol, Mw/Mn = 1.34, T = 10.1 C). However, the use of higher ethylene pressures (3 psi) resulted in the formation of a random copolymer containing 36 mol% cyclopentene (M = 133000g/mol,Mw/Mn = 1.24, T =—A.S°C). Tri- and multiblock copolymers were synthesized in which the constituent blocks differed in their cyclopentene content. 

In addition to cyclopentene, copolymers from ethylene and norbornene have also been made using 31/MAO (Yoon et al, 2006). With this catalyst, a high molecular weight, low PDI poly(E-co-NB) sample was prepared (M = 238 000 g/mol, MJM = 1.05) containing 62 mol% ethylene and a Fg of 86.5 °C. In addition, 31/MAO was also used to synthesize a high molecular weight poly(E-co-P)-Moc/ -poly(E-co-NB) sample (M = 576 000 g/mol, Mw/Mn = 1.13). 

In addition to propylene, Coates and coworkers reported that 43a-c when activated with MAO at 0 and 20 °C aU produced PE that exhibited a narrow molecular-weight distribution 

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