Gauging Iron-Sulfur Cubane Reactivity from Covalency: Trends with Oxidation State.
JACS Au
; 4(4): 1315-1322, 2024 Apr 22.
Article
em En
| MEDLINE
| ID: mdl-38665672
ABSTRACT
We investigated room-temperature metal and ligand K-edge X-ray absorption (XAS) spectra of a complete redox series of cubane-type iron-sulfur clusters. The Fe K-edge position provides a qualitative but convenient alternative to the traditional spectroscopic descriptors used to identify oxidation states in these systems, which we demonstrate by providing a calibration curve based on two analytic methods. Furthermore, high energy resolution fluorescence detected XAS (HERFD-XAS) at the S K-edge was used to measure Fe-S bond covalencies and record their variation with the average valence of the Fe atoms. While the Fe-S(thiolate) covalency evolves linearly, gaining 11 ± 0.4% per bond and hole, the Fe-S(µ3) covalency evolves asystematically, reflecting changes in the magnetic exchange mechanism. A strong discontinuity manifested for superoxidation to the all-ferric state, distinguishing its electronic structure and its potential (bio)chemical role from those of its redox congeners. We highlight the functional implications of these trends for the reactivity of iron-sulfur cubanes.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
País/Região como assunto:
Cuba
Idioma:
En
Revista:
JACS Au
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
Suíça
País de publicação:
Estados Unidos