Large ground-state entropy changes for hydrogen atom transfer reactions of iron complexes.

  title={Large ground-state entropy changes for hydrogen atom transfer reactions of iron complexes.},
  author={Elizabeth A. Mader and Ernest R. Davidson and James M. Mayer},
  journal={Journal of the American Chemical Society},
  volume={129 16},
Reported herein are the hydrogen atom transfer (HAT) reactions of two closely related dicationic iron tris(alpha-diimine) complexes. FeII(H2bip) (iron(II) tris[2,2'-bi-1,4,5,6-tetrahydropyrimidine]diperchlorate) and FeII(H2bim) (iron(II) tris[2,2'-bi-2-imidazoline]diperchlorate) both transfer H* to TEMPO (2,2,6,6-tetramethyl-1-piperidinoxyl) to yield the hydroxylamine, TEMPO-H, and the respective deprotonated iron(III) species, FeIII(Hbip) or FeIII(Hbim). The ground-state thermodynamic… Expand
Trends in ground-state entropies for transition metal based hydrogen atom transfer reactions.
Reported herein are thermochemical studies of hydrogen atom transfer (HAT) reactions involving transition metal H-atom donors M(II)LH and oxyl radicals. [Fe(II)(H(2)bip)(3)](2+),Expand
Spin-forbidden hydrogen atom transfer reactions in a cobalt biimidazoline system
Described here are hydrogen atom transfer (HAT) reactions from high-spin cobalt(II) tris(2,2′-bi-2-imidazoline) (CoIIIIH22bim) to the hydrogen atom acceptors, 2,2,6,6-tetramethyl-1-piperidinyl-oxylExpand
Hydrogen atom transfer reactions of a ruthenium imidazole complex: hydrogen tunneling and the applicability of the Marcus cross relation.
  • Adam Wu, J. Mayer
  • Chemistry, Medicine
  • Journal of the American Chemical Society
  • 2008
These data provide a test of the applicability of the Marcus cross relation for H and D transfers, over a range of temperatures, for a reaction that involves substantial tunneling. Expand
Protonation and concerted proton-electron transfer reactivity of a bis-benzimidazolate ligated [2Fe-2S] model for Rieske clusters.
The reaction with TEMPO is the first well-defined example of concerted proton-electron transfer (CPET) at a synthetic ferric/ferrous [Fe-S] cluster. Expand
Heme-FeIII Superoxide, Peroxide and Hydroperoxide Thermodynamic Relationships: FeIII-O2•- Complex H-Atom Abstraction Reactivity.
To the best of the knowledge, this is the first case where experimentally derived thermodynamics (reduction potential and pKa) lead to a ferric heme hydroperoxide OO-H BDFE determination, that FeIII-OOH species being formed via HAT reactivity of the partner ferricheme superoxide complex. Expand
Switchover of the Mechanism between Electron Transfer and Hydrogen-Atom Transfer for a Protonated Manganese(IV)-Oxo Complex by Changing Only the Reaction Temperature.
The present results provide a valuable and general guide to predict a switchover of the reaction mechanism from ET to the others, including HAT. Expand
Radical Reactivity of the Fe(III)/(II) Tetramesitylporphyrin Couple: Hydrogen Atom Transfer, Oxyl Radical Dissociation, and Catalytic Disproportionation of a Hydroxylamine.
Both (T MP)FeII and (TMP)FeIII(OH) are catalysts for the disproportionation of excess TEMPO-H to T EMPO and TEMP-H (2,2,6,6-tetramethylpiperdine). Expand
Concerted proton-electron transfer in a ruthenium terpyridyl-benzoate system with a large separation between the redox and basic sites.
To understand how the separation between the electron and proton-accepting sites affects proton-coupled electron transfer (PCET) reactivity, we have prepared ruthenium complexes withExpand
Steric and Electronic Influence on Proton-Coupled Electron-Transfer Reactivity of a Mononuclear Mn(III)-Hydroxo Complex.
The DFT calculations, which reproduce the experimental activation free energies quite well, provide the first examination of the transition-state structure of mononuclear Mn(III)(OH) species during a CPET reaction. Expand
Mechanistic Insights into C-H Oxidations by Ruthenium(III)-Pterin Complexes: Impact of Basicity of the Pterin Ligand and Electron Acceptability of the Metal Center on the Transition States.
The more basic 2OX attracts a proton from a C-H bond via a more polarized transition state than that of 1OX; on the contrary, the more electron-deficient 1OX forms less polarized transition states in PCET oxidation reactions of C- H bonds. Expand


Biomimetic oxidations catalyzed by transition metal complexes
Thermodynamic influences of C-H bond oxidation, J.M. Mayer distinguishing biomimetic oxidations from oxidations mediated by freely diffusing radicals, K.U. Ingold, P.A. MacFaul biomimeticExpand