Ethylene dimerization/polymerization catalyzed by (adamantylimido) vanadium(V) complexes containing (2-anilidomethyl)pyridine ligands: Factors affecting the ethylene reactivity

摘要

V(N-1-adamantyl)Cl _2[2-(2,6-Me _2C _6H _3)NCH _2(C _5H _4N)] showed both remarkable activity and selectivity (from 92 through <99.5% selectivity) in ethylene dimerization in the presence of MAO or MMAO, and the activity increased linearly upon increasing the ethylene pressure. The same reaction in the presence of Et _2AlCl or Me _2AlCl afforded ultrahigh molecular weight polyethylene. Both the ESR spectra and the ~(51)V NMR spectra suggest that the chelate anionic donor ligand plays an important role in stabilization of the oxidation state in the catalyst solution even containing Al alkyls.