Selectivity and Mechanism of Hydrogen Atom Transfer by an Isolable Imidoiron (III) Complex Metadata

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Title

  • Main Title Selectivity and Mechanism of Hydrogen Atom Transfer by an Isolable Imidoiron (III) Complex

Creator

  • Author: Cowley, Ryan E.
    Creator Type: Personal
    Creator Info: University of Rochester
  • Author: Eckert, Nathan A.
    Creator Type: Personal
    Creator Info: University of Rochester
  • Author: Vaddadi, Sridhar
    Creator Type: Personal
    Creator Info: University of North Texas
  • Author: Figg, Travis M.
    Creator Type: Personal
    Creator Info: University of North Texas
  • Author: Cundari, Thomas R., 1964-
    Creator Type: Personal
    Creator Info: University of North Texas
  • Author: Holland, Patrick L.
    Creator Type: Personal
    Creator Info: University of Rochester

Publisher

  • Name: American Chemical Society
    Place of Publication: [Washington, D.C.]

Date

  • Creation: 2011-05-12

Language

  • English

Description

  • Content Description: This article discusses a mechanistic study of hydrogen atom transfer by an isolable iron (III) imido complex, LᴹᵉFeNAd (Lᴹᵉ = bulky β-diketiminate ligand, 2,4-bis(2,6-diisopropylphenylimido)pentyl; Ad = 1-adamantyl).
  • Physical Description: 16 p.

Subject

  • Keyword: hydrogen atom transfers
  • Keyword: iron-imido complexes
  • Keyword: kinetic isotopes
  • Keyword: ligands

Source

  • Journal: Journal of the American Chemical Society, 2011, Washington DC: American Chemical Society, pp. 9796-9811

Citation

  • Publication Title: Journal of the American Chemical Society
  • Volume: 133
  • Issue: 25
  • Page Start: 9796
  • Page End: 9811
  • Peer Reviewed: True

Collection

  • Name: UNT Scholarly Works
    Code: UNTSW

Institution

  • Name: UNT College of Arts and Sciences
    Code: UNTCAS

Rights

  • Rights Access: public

Resource Type

  • Article

Format

  • Text

Identifier

  • DOI: 10.1021/ja2005303
  • Archival Resource Key: ark:/67531/metadc107786

Degree

  • Academic Department: Chemistry
  • Academic Department: Center for Advanced Scientific Computing and Modeling

Note

  • Display Note: Reprinted with permission from the Journal of the American Chemical Society. Copyright 2011 American Chemical Society.
  • Display Note: Abstract: In the literature, iron-oxo complexes have been isolated and their hydrogen atom transfer (HAT) reactions have been studied in detail. Iron-imido complexes have been isolated more recently, and the community needs experimental evaluations of the mechanism of HAT from late-metal imido species. The authors report a mechanistic study of HAT by an isolable iron (III) imido complex, LᴹᵉFeNAd (Lᴹᵉ = bulky β-diketiminate ligand, 2,4-bis(2,6-diisopropylphenylimido)pentyl; Ad = 1-adamantyl). HAT is preceded by binding of tert-butylpyridine (ᵗBupy) to form a reactive four-coordinate intermediate LᴹᵉFe(NAd)(ᵗBupy), as shown by equilibrium and kinetic studies. In the HAT step, very large substrate H/D kinetic isotope effects around 100 are consistent with C-H bond cleavage. The elementary HAT rate constant is increased by electron-donating groups on the pyridine additive, and by a more polar medium. When combined with the faster rate of HAT from indene versus cyclohexadiene, this trend is consistent with H⁺ transfer character in the HAT transition state. The increase in HAT rate in the presence of ᵗBupy may be explained by a combination of electronic (weaker Fe=N π-bonding) and thermodynamic (more exothermic HAT) effects. Most importantly, HAT by these imido complexes has a strong dependence on the size of the hydrocarbon substrate. This selectivity comes from steric hindrance by the spectator ligands, a strategy that has promise for controlling the regioselectivity of these C-H bond activation reactions.