title: Direct observation of insertion events at rac-(C2H4(1-indenyl)2)Zr(MeB(C6F5)3)-polymeryl intermediates: distinction between continuous and intermittent propagation modes.
abstract: The propagating species for 1-hexene, propene, and ethene polymerization as catalyzed by [rac-(C2H4(1-indenyl)2)Zr(CH3)][CH3B(C6F5)3] has been intercepted at T < -40 degrees C and characterized by NMR methods. Observation of the propagating species permits direct monitoring of initiation, propagation, and termination processes by NMR. Detailed examination of alkene incorporation into Zr-polymeryl species using 13C-labeled 1-alkenes supports a continuous insertion mechanism whereby the anion re-coordinates after each alkene insertion.
authors.affiliation: Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA.
authors.forename: Clark R
authors.initials: CR
authors.lastname: Landis
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Rosaaen
authors.forename: Douglass R
authors.initials: DR
authors.lastname: Sillars
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D007192:Indenes / Q000737:chemistry*; D007700:Kinetics; D009942:Organometallic Compounds / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D000475:Alkenes; D007192:Indenes; D009942:Organometallic Compounds; D011108:Polymers; D015040:Zirconium