Open AccessDirect Aerobic Generation of a Ferric Hydroperoxo Intermediate Via a Preorganized Secondary Coordination Sphere
Author(s) -
Kate Jesse,
Sophie W. Anferov,
Kelsey A. Collins,
Juan A. Valdez-Moreira,
Maia E. Czaikowski,
Alexander S. Filatov,
John S. Anderson
Publication year - 2021
Publication title -
journal of the american chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.115
H-Index - 612
eISSN - 1520-5126
pISSN - 0002-7863
DOI - 10.1021/jacs.1c06911
Subject(s) - coordination sphere , chemistry , ligand (biochemistry) , coordination complex , oxidizing agent , reactivity (psychology) , photochemistry , proton , electron transfer , metal , coordination number , outer sphere electron transfer , radical , primary (astronomy) , combinatorial chemistry , stereochemistry , organic chemistry , ion , astronomy , medicine , biochemistry , physics , receptor , alternative medicine , pathology , quantum mechanics
Enzymes exert control over the reactivity of metal centers with precise tuning of the secondary coordination sphere of active sites. One particularly elegant illustration of this principle is in the controlled delivery of proton and electron equivalents in order to activate abundant but kinetically inert oxidants such as O 2 for oxidative chemistry. Chemists have drawn inspiration from biology in designing molecular systems where the secondary coordination sphere can shuttle protons or electrons to substrates. However, a biomimetic activation of O 2 requires the transfer of both protons and electrons, and molecular systems where ancillary ligands are designed to provide both of these equivalents are comparatively rare. Here, we report the use of a dihydrazonopyrrole (DHP) ligand complexed to Fe to perform exactly such a biomimetic activation of O 2 . In the presence of O 2 , this complex directly generates a high spin Fe(III)-hydroperoxo intermediate which features a DHP • ligand radical via ligand-based transfer of an H atom. This system displays oxidative reactivity and ultimately releases hydrogen peroxide, providing insight on how secondary coordination sphere interactions influence the evolution of oxidizing intermediates in Fe-mediated aerobic oxidations.