In:
Angewandte Chemie, Wiley, Vol. 133, No. 11 ( 2021-03-08), p. 5972-5977
Abstract:
A new end‐on low‐spin ferric heme peroxide, [(P Im )Fe III −(O 2 2− )] − ( P Im ‐ P ), and subsequently formed hydroperoxide species, [(P Im )Fe III −(OOH)] ( P Im ‐ HP ) are generated utilizing the iron‐porphyrinate P Im with its tethered axial base imidazolyl group. Measured thermodynamic parameters, the ferric heme superoxide [(P Im )Fe III −(O 2 ⋅− )] ( P Im ‐ S ) reduction potential ( E °′) and the P Im ‐ HP p K a value, lead to the finding of the OO−H bond‐dissociation free energy (BDFE) of P Im ‐ HP as 69.5 kcal mol −1 using a thermodynamic square scheme and Bordwell relationship. The results are validated by the observed oxidizing ability of P Im ‐ S via hydrogen‐atom transfer (HAT) compared to that of the F 8 superoxide complex, [(F 8 )Fe III −(O 2 .− )] ( S ) (F 8 =tetrakis(2,6‐difluorophenyl)porphyrinate, without an internally appended axial base imidazolyl), as determined from reactivity comparison of superoxide complexes P Im ‐ S and S with the hydroxylamine (O‐H) substrates TEMPO‐H and ABNO‐H.
Type of Medium:
Online Resource
ISSN:
0044-8249
,
1521-3757
DOI:
10.1002/ange.v133.11
DOI:
10.1002/ange.202013791
Language:
English
Publisher:
Wiley
Publication Date:
2021
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