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Updated: Jun 19, 2026

Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
Published on: July 27, 2022
Evidence for a rapid degenerate hetero-Cope-type rearrangement in [Cp*W(S)2S-CH2-CH=CH2]
Florian Eweiner1, Shunsuke Senda2, Klaus Bergander1
1Organisch-Chemisches Institut, Westfälische Wilhelms Universität Münster, Corrensstraße 40,D-48149 Münster (Germany), Fax: (+49) 251-83-36503.
Abstract:
Treatment of the salt [PPh(4)]+[Cp*W(S)3]- (6) with allyl bromide gave the neutral complex [Cp*W(S)2S-CH2-CH=CH2] (7). The product 7 was characterized by an X-ray crystal structure analysis. Complex 7 features dynamic NMR spectra that indicate a rapid allyl automerization process. From the analysis of the temperature-dependent NMR spectra a Gibbs activation energy of DeltaG(not equal) (278 K) approximately 13.7+/-0.1 kcal mol(-1) was obtained [DeltaH(not equal) approximately 10.4+/-0.1 kcal mol(-1); DeltaS(not equal) approximately -11.4 cal mol(-1) K(-1)]. The DFT calculation identified an energetically unfavorable four-membered transition state of the "forbidden" reaction and a favorable six-membered transition state of the "Cope-type" allyl rearrangement process at this transition-metal complex core.
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