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Cobalt Superoxo and Alkylperoxo Complexes Derived from Reaction of Ring-Cleaving Dioxygenase Models with O2.

ABSTRACT: The syntheses and O2 reactivities of active-site models of cobalt-substituted ring-cleaving dioxygenases are presented. The pentacoordinate cobalt(II)-aminophenolate complex, [Co(TpMe2)(tBu2APH)], gives rise to two distinct dioxygen adducts at reduced temperatures. The first is a paramagnetic (S = 1/2) cobalt(III)-superoxo species that was characterized with spectroscopic and computational techniques. The identity of the second Co/O2 adduct was elucidated by X-ray crystallography, which revealed an unprecedented cobalt(III)-alkylperoxo structure generated by O2 addition to the metal ion and ligand. These results provide synthetic precedents for proposed intermediates in the catalytic cycles of O2-activating cobalt enzymes.

SUBMITTER: Kumar P

PROVIDER: S-EPMC6748656 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature

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Cobalt Superoxo and Alkylperoxo Complexes Derived from Reaction of Ring-Cleaving Dioxygenase Models with O2.

Kumar Praveen P Lindeman Sergey V SV Fiedler Adam T AT

Journal of the American Chemical Society 20190705 28

The syntheses and O2 reactivities of active-site models of cobalt-substituted ring-cleaving dioxygenases are presented. The pentacoordinate cobalt(II)-aminophenolate complex, [Co(TpMe2)(tBu2APH)], gives rise to two distinct dioxygen adducts at reduced temperatures. The first is a paramagnetic (S = 1/2) cobalt(III)-superoxo species that was characterized with spectroscopic and computational techniques. The identity of the second Co/O2 adduct was ...[more]

PMID: 31251607

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