Heterobi- and -trimetallic Ion Pairs of Zirconocene-Based Isoselective Olefin Polymerization Catalysts with AlMe3. - Université de Rennes Access content directly
Journal Articles Angewandte Chemie International Edition Year : 2015

Heterobi- and -trimetallic Ion Pairs of Zirconocene-Based Isoselective Olefin Polymerization Catalysts with AlMe3.

Abstract

The reactivity towards AlMe3 of discrete cationic ansa-zirconocenes 2 a,b that are ubiquitously used in isoselective propylene polymerization and based on [{Ph(H)C(3,6-tBu2-Flu)(3-tBu-5-Et-Cp)}ZrMe2)] {Cp-Flu} and rac-[{Me2Si-(2-Me-4-Ph-Ind)2}ZrMe2] {SBI} was scrutinized. The first example of a structurally characterized Group 4 metallocene AlMe3 adduct (3 b) is reported. In the presence of excess AlMe3, the {SBI}-based AlMe3 adduct 3 b undergoes a slow decomposition via C[BOND]H activation in a bridging methyl unit to yield a new species (4 b) with a trimetallic {Zr(μ-CH2)(μ-Me)AlMe(μ-Me)AlMe2} core. EXSY NMR data for the process 2 b⇄3 b[RIGHTWARDS ARROW]4 b suggest very rapid and reversible binding of an additional AlMe3 molecule onto AlMe3 adduct 3 b. The resulting heterotrimetallic species intermediates exchange of methyl groups between different metal centers and slowly undergoes the C[BOND]H activation reaction towards 4 b.

Dates and versions

hal-01142068 , version 1 (14-04-2015)

Identifiers

Cite

Gabriel Theurkauff, Arnaud Bondon, Vincent Dorcet, Jean-François Carpentier, Evgueni Kirillov. Heterobi- and -trimetallic Ion Pairs of Zirconocene-Based Isoselective Olefin Polymerization Catalysts with AlMe3.. Angewandte Chemie International Edition, 2015, 54 (21), pp.6343-6346. ⟨10.1002/anie.201501967⟩. ⟨hal-01142068⟩
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