Heavy-Atom Kinetic Isotope Effects, Cocatalysts, and the Propagation Transition State for Polymerization of 1-Hexene Using the rac-(C2H4(1-indenyl)2)ZrMe2<

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• 作者：Clark R. Landis ; Kimberly A. Rosaaen ; and Jamal Uddin
• 刊名：Journal of the American Chemical Society
• 出版年：2002
• 出版时间：October 16, 2002
• 年：2002
• 卷：124
• 期：41
• 页码：12062 - 12063
• 全文大小：41K
• 年卷期：v.124,no.41(October 16, 2002)
• ISSN：1520-5126

文摘

Using ¹³C NMR techniques, the ¹²C/¹³C kinetic isotope effects (KIEs) for the polymerization of 1-hexene catalyzed by rac-(C₂H₄(1-indenyl)₂)ZrMe₂ in the presence of four different cocatalysts (tris(pentfluorophenyl)borane, tris(pentafluorophenyl)alane, anilinium tetrakis(pentafluorophenyl)borate, and methylalumoxane) have been determined. All cocatalysts yield similar KIEs within experimental uncertainty, with values of 1.009(1) and 1.017(2) at C₁ and C₂, respectively. Ab initio DFT computational modeling of the polymerization KIE indicates that alkene binding to the catalyst must be reversible, with the majority of the KIE developing in the subsequent migratory insertion reaction.