Bis phosphanylphenoxide titanium Catalysts

To enhance the living nature of the system, Li and coworkers explored the copolymerization of norbomene and ethylene. They found that the copolymerization of ethylene and norbomene by 52g/MAO resulted in polymers with narrow molecular-weight distributions (M /Mn 1.2) 

Alternatively, living propylene polymerization behavior was not observed for the hafnium analog (roc-56b), however, living isoselective polymerization of propylene was observed for the zirconium analog (rac-56a). At 0°C, rac-56a/B(CeF5)3 produced polypropylene with 

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