Amine Catalyzed Solvent C-H Bond Activation as Deactivation Route for Cationic Decamethylzirconocene Olefin Polymerization Catalysts

[Cp(2)ZrMe)(+) + Me(3)N + C(6)H(6)

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Cp(2)ZrMePh + (Me(3)NH](+)

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[Cp(2)ZrPh](+) + Me(3)N + CH(4)

The C-D activation of bromobenzene-d(5), by [CP(2)*ZrMe(BrC(6)D(5)-kappa Br)][B(C(6)F(5))(4)] to form sigma-aryl complex [Cp(2)*Zr(2-BrC(6)D(4)-kappa(2)Br,C)][B(C(6)F(5))(4)] is accelerated when the decamethylzirconocene methyl cation is generated in the presence of tertiary amines. Computational studies suggest that the overall sigma-bond metathesis reaction proceeds, in the presence of tertiary amines, via initial deprotonation of bromobenzene in the coordination sphere of the metal center. In a subsequent step, the resulting neutral methyl aryl species, CP(2)*ZrMe(2-BrC(6)D(4)), reacts with the concurrently generated trialkylammonium cation to generate [Cp(2)*Zr(2-BrC(6)D(4)-kappa(2)Br,C)][B(C(6)F(5))(4)].