title: Reactive intermediates formed during olefin polymerization by methylalumoxane-activated ansa-zirconocene catalysts: identification of a chain-carrying intermediate by NMR methods.
abstract: Addition of 1-hexene to methylalumoxane-activated catalyst systems based on rac-Me(2)Si(ind)(2)ZrMe(2) causes, concurrent with polyhexene formation and diminution of the otherwise prevalent cation [rac-Me(2)Si(ind)(2)Zr(mu-Me)(2)AlMe(2)](+), formation of a hitherto unobserved species [rac-Me(2)Si(ind)(2)Zr(mu-R)(mu-Me)AlMe(2)](+), where R is a Zr-bound polyhexyl chain. As hexene is increasingly consumed, this cation decays, mainly back to [rac-Me(2)Si(ind)(2)Zr(mu-Me)(2)AlMe(2)](+) and, in part, to some species containing a Zr-bound allylic chain end.
authors.affiliation: Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Science, Pr. Lavrentieva 5, Novosibirsk, RU-630090, Russia. Dimi@catalysis.ru
authors.forename: Dmitrii E
authors.initials: DE
authors.lastname: Babushkin
authors.forename: Hans H
authors.initials: HH
authors.lastname: Brintzinger
mesh_terms: D000475:Alkenes / Q000138:chemical synthesis* / Q000737:chemistry*; D000535:Aluminum / Q000737:chemistry*; D002384:Catalysis; D009682:Magnetic Resonance Spectroscopy; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013997:Time Factors; D015040:Zirconium / Q000737:chemistry*
chemical_list: D000475:Alkenes; D009942:Organometallic Compounds; C023398:Zirconocene dichloride; D015040:Zirconium; D000535:Aluminum