Notable Effects of Aluminum Alkyls and Solvents for Highly Efficient Ethylene (Co)polymerizations Catalyzed by (Arylimido)‐ (aryloxo)vanadium Complexes

The effects of both Al cocatalyst and solvent on catalytic activity in the ethylene polymerization by the (arylmido)(aryloxo)vanadium(V) complex, VCl 2 (N‐2,6‐Me 2 C 6 H 3 )(O‐2,6‐Me 2 C 6 H 3 ) ( 1 ), have been explored in detail. The activity of 5.84×10 5 kg PE/mol V⋅h (TOF 2.08×10 7 h −1 ) has been achieved by 1 /EtAlCl 2 catalyst in CH 2 Cl 2 at 0 °C, and the activity in toluene increased in the order: i ‐Bu 2 AlCl>EtAlCl 2 >Me 2 AlCl>Et 2 AlCl> Et 2 Al(OEt), AlEt 3 , AlMe 3 (negligible activities). Both aluminum alkyl cocatalyst and solvent also affected the catalytic activity and the norbornene (NBE) incorporation in the ethylene/NBE copolymerization using complex 1 , whereas the NBE contents were not strongly affected by the kind of aryl oxide ligand in VCl 2 (N‐2,6‐Me 2 C 6 H 3 )(OAr) [OAr=O‐2,6‐Me 2 C 6 H 3 ( 1 ), O‐2,6‐ i ‐Pr 2 C 6 H 3 ( 2 ), O‐2,6‐Ph 2 C 6 H 3 ( 3 )].