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π-Frontier molecular orbitals in S = 2 ferryl species and elucidation of their contributions to reactivity.

ABSTRACT: S = 2 Fe(IV) ═ O species are key intermediates in the catalysis of most nonheme iron enzymes. This article presents detailed spectroscopic and high-level computational studies on a structurally-defined S = 2 Fe(IV) ═ O species that define its frontier molecular orbitals, which allow its high reactivity. Importantly, there are both π- and σ-channels for reaction, and both are highly reactive because they develop dominant oxyl character at the transition state. These π- and σ-channels have different orientation dependences defining how the same substrate can undergo different reactions (H-atom abstraction vs. electrophilic aromatic attack) with Fe(IV) ═ O sites in different enzymes, and how different substrates can undergo different reactions (hydroxylation vs. halogenation) with an Fe(IV) ═ O species in the same enzyme.

SUBMITTER: Srnec M

PROVIDER: S-EPMC3437891 | biostudies-literature | 2012 Sep

REPOSITORIES: biostudies-literature

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π-Frontier molecular orbitals in S = 2 ferryl species and elucidation of their contributions to reactivity.

Srnec Martin M Wong Shaun D SD England Jason J Que Lawrence L Solomon Edward I EI

Proceedings of the National Academy of Sciences of the United States of America 20120820 36

S = 2 Fe(IV) ═ O species are key intermediates in the catalysis of most nonheme iron enzymes. This article presents detailed spectroscopic and high-level computational studies on a structurally-defined S = 2 Fe(IV) ═ O species that define its frontier molecular orbitals, which allow its high reactivity. Importantly, there are both π- and σ-channels for reaction, and both are highly reactive because they develop dominant oxyl character at the transition state. These π- and σ-channels have differe ...[more]

PMID: 22908238

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