556065-18-0Relevant academic research and scientific papers
Structure/activity relationships for the living Ziegler-Natta polymerization of 1-hexene by the series of cationic monocyclopentadienyl zirconium acetamidinate complexes
Kissounko, Denis A.,Fettinger, James C.,Sita, Lawrence R.
, p. 121 - 129 (2008/10/08)
Protonation of (η5-C5Me5)ZrMe2[N(t-Bu)C(Me) N(CH2R)] (1) [R=(a) Me, (b) i-Pr, (c) t-Bu, (d) Ph, (e) 2-ClC6H4, (f) 3-MeC6H4 and (g) 2,4,6-Me3C6H2] by [PhNMe2H][B(C6F5)4] in chlorobenzene at -10°C provides the titled cationic complexes 2a-g. Both 2b and 2d are active initiators for the living polymerization of 1-hexene at -10°C, however, whereas 2d functions much like 2a in terms of activity and isoselectivity, propagation from 2b is much less active and it produces atactic material. Complexes 2d and 2g are inactive, presumably due to steric reasons, while intramolecular chloride coordination appears responsible for inhibiting 2e. Finally, 2f, while active as an initiator, was found not to provide a living system as a result of C-H activation processes that terminate propagation. A structural study of the precatalysts 1b-d sheds additional light on the nature of ligand effects on activity and stereocontrol for the family of initiators represented by 2.
