An EPR Study of the V(IV) Species Formed Upon Activation of a Vanadyl Phenoxyimine Polymerization Catalyst with AlR3 and AlR2Cl (R = Me, Et)

Igor E. Soshnikov, Nina V. Semikolenova, Konstantin P. Bryliakov, Alexander A. Shubin, Vladimir A. Zakharov, Carl Redshaw, Evgenii P. Talsi

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Abstract

Vanadium(IV) complexes formed in the systems L2VIVO/AlR3, L2VIVO/AlR3/ETA, L2VIVO/AlR2Cl, and L2VIVO/AlR2Cl/ETA, where L is a phenoxyimine ligand (Scheme 1), R = Me or Et, and ETA is ethyltrichloroacetate, were monitored by EPR. It was shown, that at 20 °C, V(IV) complexes with proposed structures (L′)VIV(O)(R)(AlR3) are formed in the systems L2VIVO/AlR3 and L2VIVO/AlR3/ETA, whereas complexes with proposed structures (L′)VIV(O)(R)(AlR2Cl) are formed in the systems L2VIVO/AlR2Cl and L2VIVO/AlR2Cl/ETA (L′ is the modified initial ligand). The systems L2VIVO/AlR3/ETA are inert towards polymerization of ethylene, whereas the systems L2VIVO/AlR2Cl/ETA are moderately active in this reaction. The polymerization activity of the systems L2VIVO/AlR2Cl/ETA correlates with the concentration of V(IV) species present in the reaction solution. V(IV) complexes of the type (L′)VIV(O)(R)(AlR2Cl) can be precursors of the active species of polymerization.
Original languageEnglish
Pages (from-to)542-548
Number of pages7
JournalMacromolecular Chemistry and Physics
Volume210
Issue number7
Early online date4 Mar 2009
DOIs
Publication statusPublished - 2 Apr 2009

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