NMR and EPR trapping of the active species in the ethylene polymerization and trimerization catalyst systems

Abstract

Abstract:In this work, previously undetected intermediates of several practically promising catalyst systems for ethylene polymerization and trimerization are discussed. In particular, the activation of ethylene polymerization catalysts (1) LNiCl 2 (L = 2,4,6-trimethyl-(N-5,6,7-trihydroquinolin-8-ylidene)phenylamine) with AlEt 2 Cl and AlMe 2 Cl, (2)

Alkene oligomerization via metallacycles: Recent advances and mechanistic insights

“…NMR and EPR Spectroscopic studies, by Talsi and co-workers have highlighted the formation of Ti II , Ti III and Ti IV mixtures from (FI)TiCl 3 , which relative proportions depended on the aluminium cocatalyst. [31,32] Adding AlR 3 (R = Me, Et) on (FI)TiCl 3 leaded to the formation of neutral Ti (II) species according to NMR studies. Repeating the same experiment with one equivalent of [CPh 3 ][B(C 6 F 5 ) 4 ] induced the formation of a cationic Ti(II) species.…”