Generation of [(N4Py)Fe(IV)═O]2+ through Heterolytic O-O Bond Cleavage in [(N4Py)Fe(II)(OOH)]+

Juan Chen, Andy S. Sardjan, C. Maurits de Roo, Marika Di Berto Mancini, Apparao Draksharapu, Davide Angelone, Ronald Hage, Marcel Swart*, Wesley R. Browne*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

1 Citation (Scopus)
5 Downloads (Pure)

Abstract

High-valent Fe(IV) oxido species are important intermediates in the catalyzed oxidation of organic compounds by nonheme iron enzymes. These species can be generated in biomimetic model complexes directly using oxygen atom transfer oxidants, e.g., PhIO and ClO-. Their formation by heterolysis of the O-O bond of putative Fe(II)-OOH species (formed from Fe(II) precursors and H2O2) has scarcely been observed. Reaction with near-stoichiometric H2O2 typically shows initial formation of Fe(III)-OH and Fe(III)-OOH species, with homolytic O-O bond cleavage thereafter proposed to generate the Fe(IV)═O state. Here, we show that [(N4Py)Fe(IV)═O]2+ (where N4Py = 1,1-di(pyridin-2-yl)-N,N-bis(pyridin-2-ylmethyl)methanamine) is formed with substoichiometric H2O2 in methanol through heterolytic cleavage of the O-O bond of an Fe(II)-OOH intermediate. Temperature-dependent studies show that the ligand exchange reactions preceding formation of the Fe(II)-OOH species and subsequent comproportionations limit the yield of the Fe(IV)═O species. Furthermore, comproportionation proceeds through hydrogen atom transfer from [(N4Py)Fe(II)(OH2)]2+ to [(N4Py)Fe(IV)═O]2+. These data rationalize the extent of the initial conversion of [(N4Py)Fe(II)(CH3CN)]2+ to [(N4Py)Fe(IV)═O]2+ under conditions relevant to catalytic oxidations. The heterolytic pathway to formation of [(N4Py)Fe(IV)═O]2+ is a key step in the development of iron(II) oxidation catalysts that can cycle between the Fe(II) and Fe(IV)═O states, avoiding nonselective reactive oxygen species.

Original languageEnglish
Article number4c05172
Pages (from-to)9408–9417
Number of pages10
JournalInorganic Chemistry
Volume64
Issue number19
Early online date2-May-2025
DOIs
Publication statusPublished - 19-May-2025

Fingerprint

Dive into the research topics of 'Generation of [(N4Py)Fe(IV)═O]2+ through Heterolytic O-O Bond Cleavage in [(N4Py)Fe(II)(OOH)]+'. Together they form a unique fingerprint.

Cite this