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The chameleon-like nature of elusive cobalt-oxygen intermediates in C-H bond activation reactions
- Title
- The chameleon-like nature of elusive cobalt-oxygen intermediates in C-H bond activation reactions
- Authors
- Zhou A.; Cao X.; Chen H.; Sun D.; Zhao Y.; Nam W.; Wang Y.
- Ewha Authors
- 남원우
- SCOPUS Author ID
- 남원우
![scopus](/images/layout/icon2.png)
- Issue Date
- 2022
- Journal Title
- Dalton Transactions
- ISSN
- 1477-9226
- Citation
- Dalton Transactions vol. 51, no. 11, pp. 4317 - 4323
- Publisher
- Royal Society of Chemistry
- Indexed
- SCIE; SCOPUS
![scopus](/images/layout/scopus2.gif)
- Document Type
- Article
- Abstract
- High-valence metal-oxo (M-O, M = Fe, Mn, etc.) species are well-known reaction intermediates that are responsible for a wide range of pivotal oxygenation reactions and water oxidation reactions in metalloenzymes. Although extensive efforts have been devoted to synthesizing and identifying such complexes in biomimetic studies, the structure-function relationship and related reaction mechanisms of these reaction intermediates remain elusive, especially for the cobalt-oxygen species. In the present manuscript, the calculated results demonstrate that the tetraamido macrocycle ligated cobalt complex, Co(O)(TAML) (1), behaves like a chameleon: the electronic structure varies from a cobalt(iii)-oxyl species to a cobalt(iv)-oxo species when a Lewis acid Sc3+ salt coordinates or an acidic hydrocarbon attacks 1. The dichotomous correlation between the reaction rates of C-H bond activation by 1 and the bond dissociation energy (BDE) vs. the acidity (pKa) was rationalized for the first time by different reaction mechanisms: for normal C-H bond activation, the Co(iii)-oxyl species directly activates the C-H bond via a hydrogen atom transfer (HAT) mechanism, whereas for acidic C-H bond activation, the Co(iii)-oxyl species evolves to a Co(iv)-oxo species to increase the basicity of the oxygen to activate the acidic C-H bond, via a novel PCET(PT) mechanism (proton-coupled electron transfer with a PT(proton-transfer)-like transition state). These theoretical findings will enrich the knowledge of biomimetic metal-oxygen chemistry. © The Royal Society of Chemistry
- DOI
- 10.1039/d2dt00224h
- Appears in Collections:
- 자연과학대학 > 화학·나노과학전공 > Journal papers
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