Evidence for mixed-ion clusters in metallocene catalysts: Influence on ligand exchange dynamics and catalyst activity

Carlos Alonso-Moreno; Simon J. Lancaster; Cristiano Zuccaccia; Alceo Macchioni; Manfred Bochmann

doi:10.1021/ja072028h

Evidence for mixed-ion clusters in metallocene catalysts: Influence on ligand exchange dynamics and catalyst activity

Carlos Alonso-Moreno, Simon J. Lancaster, Cristiano Zuccaccia, Alceo Macchioni, Manfred Bochmann

Research output: Contribution to journal › Article › peer-review

47 Citations (Scopus)

Abstract

Alkylzirconium ion pairs [L₂Zr-CH₂SiMe₃⁺···B(C₆F₅)₄^-], as models of catalytic zirconium polymeryl species, form mixed-ion clusters [{LZrR⁺}_n{CPh₃⁺}_m{X^-}_(n+m)], as shown by pulsed field-gradient spin-echo NMR measurements. Higher ion aggregation leads to enhanced rates of site epimerization. This rate enhancement is used to probe previously inaccessible kinetic barriers for the “chain swinging” process. The presence or absence of such a barrier has implications for catalytic activity and response to ionic activators.

Original language	English
Pages (from-to)	9282-9283
Number of pages	2
Journal	Journal of the American Chemical Society
Volume	129
Issue number	30
DOIs	https://doi.org/10.1021/ja072028h
Publication status	Published - 6 Jul 2007

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10.1021/ja072028h

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abstract = "Alkylzirconium ion pairs [L2Zr-CH2SiMe3+···B(C6F5)4-], as models of catalytic zirconium polymeryl species, form mixed-ion clusters [{LZrR+}n{CPh3+}m{X-}(n+m)], as shown by pulsed field-gradient spin-echo NMR measurements. Higher ion aggregation leads to enhanced rates of site epimerization. This rate enhancement is used to probe previously inaccessible kinetic barriers for the “chain swinging” process. The presence or absence of such a barrier has implications for catalytic activity and response to ionic activators.",

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year = "2007",

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T1 - Evidence for mixed-ion clusters in metallocene catalysts: Influence on ligand exchange dynamics and catalyst activity

AU - Alonso-Moreno, Carlos

AU - Lancaster, Simon J.

AU - Zuccaccia, Cristiano

AU - Macchioni, Alceo

AU - Bochmann, Manfred

PY - 2007/7/6

Y1 - 2007/7/6

N2 - Alkylzirconium ion pairs [L2Zr-CH2SiMe3+···B(C6F5)4-], as models of catalytic zirconium polymeryl species, form mixed-ion clusters [{LZrR+}n{CPh3+}m{X-}(n+m)], as shown by pulsed field-gradient spin-echo NMR measurements. Higher ion aggregation leads to enhanced rates of site epimerization. This rate enhancement is used to probe previously inaccessible kinetic barriers for the “chain swinging” process. The presence or absence of such a barrier has implications for catalytic activity and response to ionic activators.

AB - Alkylzirconium ion pairs [L2Zr-CH2SiMe3+···B(C6F5)4-], as models of catalytic zirconium polymeryl species, form mixed-ion clusters [{LZrR+}n{CPh3+}m{X-}(n+m)], as shown by pulsed field-gradient spin-echo NMR measurements. Higher ion aggregation leads to enhanced rates of site epimerization. This rate enhancement is used to probe previously inaccessible kinetic barriers for the “chain swinging” process. The presence or absence of such a barrier has implications for catalytic activity and response to ionic activators.

U2 - 10.1021/ja072028h

DO - 10.1021/ja072028h

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JF - Journal of the American Chemical Society

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