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Identification, Characterization, and Electronic Structures of Interconvertible Cobalt-Oxygen TAML Intermediates
- Title
- Identification, Characterization, and Electronic Structures of Interconvertible Cobalt-Oxygen TAML Intermediates
- Authors
- Malik; Deesha D.; Ryu; Wooyeol; Kim; Yujeong; Singh; Gurjot; Jun-Hyeong; Sankaralingam; Muniyandi; Lee; Yong-Min; Seo; Mi Sook; Sundararajan; Mahesh; Ocampo; Daniel; Roemelt; Michael; Park; Kiyoung; Sun Hee; Baik; Mu-Hyun; Shearer; Jason; Ray; Kallol; Fukuzumi; Shunichi; Nam; Wonwoo
- Ewha Authors
- 남원우; Shunichi Fukuzumi; 이용민
- SCOPUS Author ID
- 남원우
; Shunichi Fukuzumi![scopus](/images/layout/icon2.png)
; 이용민![scopus](/images/layout/icon2.png)
![scopus](/images/layout/icon2.png)
![scopus](/images/layout/icon2.png)
- Issue Date
- 2024
- Journal Title
- Journal of the American Chemical Society
- ISSN
- 2786-7863
- Citation
- Journal of the American Chemical Society vol. 146, no. 20, pp. 13817 - 13835
- Indexed
- SCIE; SCOPUS
![scopus](/images/layout/scopus2.gif)
- Document Type
- Article
- Abstract
- The reaction of Li[(TAML)CoIII]·3H2O (TAML = tetraamido macrocyclic tetraanionic ligand) with iodosylbenzene at 253 K in acetone in the presence of redox-innocent metal ions (Sc(OTf)3 and Y(OTf)3) or triflic acid affords a blue species 1, which is converted reversibly to a green species 2 upon cooling to 193 K. The electronic structures of 1 and 2 have been determined by combining advanced spectroscopic techniques (X-band electron paramagnetic resonance (EPR), electron nuclear double resonance (ENDOR), X-ray absorption spectroscopy/extended X-ray absorption fine structure (XAS/EXAFS), and magnetic circular dichroism (MCD)) with ab initio theoretical studies. Complex 1 is best represented as an S = 1/2 [(Sol)(TAML•+)CoIII-OH(LA)]− species (LA = Lewis/Brønsted acid and Sol = solvent), where an S = 1 Co(III) center is antiferromagnetically coupled to S = 1/2 TAML•+, which represents a one-electron oxidized TAML ligand. In contrast, complex 2, also with an S = 1/2 ground state, is found to be multiconfigurational with contributions of both the resonance forms [(H-TAML)CoIV═O(LA)]− and [(H-TAML•+)CoIII═O(LA)]−; H-TAML and H-TAML•+ represent the protonated forms of TAML and TAML•+ ligands, respectively. Thus, the interconversion of 1 and 2 is associated with a LA-associated tautomerization event, whereby H+ shifts from the terminal −OH group to TAML•+ with the concomitant formation of a terminal cobalt-oxo species possessing both singlet (SCo = 0) Co(III) and doublet (SCo = 1/2) Co(IV) characters. The reactivities of 1 and 2 at different temperatures have been investigated in oxygen atom transfer (OAT) and hydrogen atom transfer (HAT) reactions to compare the activation enthalpies and entropies of 1 and 2. © 2024 American Chemical Society.
- DOI
- 10.1021/jacs.3c14346
- Appears in Collections:
- 자연과학대학 > 화학·나노과학전공 > Journal papers
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