Half-Sandwich Metal-Catalyzed Alkyne [2+2+2] Cycloadditions and the Slippage Span Model

Marco Dalla Tiezza, F. Matthias Bickelhaupt, Laura Orian

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Half-sandwich RhI compounds display good catalytic activity toward alkyne [2+2+2] cycloadditions. A peculiar structural feature of these catalysts is the coordination of the metal to an aromatic moiety, typically a cyclopentadienyl anion, and, in particular, the possibility to change the bonding mode easily by the metal slipping over this aromatic moiety. Upon modifying the ancillary ligands, or proceeding along the catalytic cycle, hapticity changes can be observed; it varies from η5, if the five metal–carbon distances are identical, through η32, in the presence of allylic distortion, and η3, in the case of allylic coordination, to η1, if a σ metal–carbon bond forms. In this study, we present the slippage span model, derived with the aim of establishing a relationship between slippage variation during the catalytic cycle, quantified in a novel and rigorous way, and the performance of catalysts in terms of turnover frequency, computed with the energy span model. By collecting and comparing new data and data from the literature, we find that the highest performance is associated with the smallest slippage variation along the cycle.

LanguageEnglish
Pages143-154
Number of pages12
JournalChemistryOpen
Volume8
Issue number2
Early online date28 Nov 2018
DOIs
Publication statusPublished - Feb 2019

Fingerprint

Alkynes
Cycloaddition
Metals
Carbon
Catalysts
Anions
Catalyst activity
Ligands

Keywords

  • cycloadditions
  • density functional calculations
  • half-metallocenes
  • reaction mechanisms
  • slippage span

Cite this

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Half-Sandwich Metal-Catalyzed Alkyne [2+2+2] Cycloadditions and the Slippage Span Model. / Dalla Tiezza, Marco; Bickelhaupt, F. Matthias; Orian, Laura.

In: ChemistryOpen, Vol. 8, No. 2, 02.2019, p. 143-154.

Research output: Contribution to JournalArticleAcademicpeer-review

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