In the present work, we have prepared
nickel phenoxyimine-polyethylene
glycol (PEG) catalysts with sterically bulky <i>N</i>-aryl
substituents and investigated their ethylene homo- and copolymerization
behavior. We have found that different nickel catalyst and alkali
ion (Na<sup>+</sup> or K<sup>+</sup>) combinations yielded polyethylene
with different branching microstructures and molecular weights. Our
heterobimetallic catalysts can copolymerize ethylene and nonpolar
α-olefins with high activity but are strongly inhibited in the
presence of polar vinyl olefins. We demonstrate that our heterobimetallic
catalysts are significantly more stable in ethylene homopolymerization
in comparison to conventional nickel phenoxyimine systems on the basis
of time-dependent activity studies. This work showcases the versatility
of Lewis acid tunable catalyst constructs to prepare customized polyolefins
and suggests that similar design strategies could be applied to other
catalyst systems
