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Title: The Oxo-Wall Remains Intact: A Tetrahedrally Distorted Co(IV)–Oxo Complex
Award ID(s):
1900380
NSF-PAR ID:
10349445
Author(s) / Creator(s):
; ; ; ; ; ; ;
Date Published:
Journal Name:
Journal of the American Chemical Society
Volume:
143
Issue:
41
ISSN:
0002-7863
Page Range / eLocation ID:
16943 to 16959
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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  1. Abstract

    High‐valent metal‐oxo species play critical roles in enzymatic catalysis yet their properties are still poorly understood. In this work we report a combined experimental and computational study into biomimetic iron(IV)‐oxo and iron(III)‐oxo complexes with tight second‐coordination sphere environments that restrict substrate access. The work shows that the second‐coordination sphere slows the hydrogen atom abstraction step from toluene dramatically and the kinetics is zeroth order in substrate. However, the iron(II)‐hydroxo that is formed has a low reduction potential and hence cannot do OH rebound favorably. The tolyl radical in solution then reacts further with alternative reaction partners. By contrast, the iron(IV)‐oxo species reacts predominantly through OH rebound to form alcohol products. Our studies show that the oxidation state of the metal influences reactivities and selectivities with substrate dramatically and that enzymes will likely need an iron(IV) center to catalyze C−H hydroxylation reactions.

     
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