biostudies-literatureGrunwald LEuropean Research Council1315-1322https://www.ebi.ac.uk/biostudies/studies/S-EPMC11040707biostudies-literatureUnknown4(4)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 exchangeJACS AuGauging Iron-Sulfur Cubane Reactivity from Covalency: Trends with Oxidation State.PMC11040707853064Mougel VAbbott DFGrunwald LfalseGauging Iron-Sulfur Cubane Reactivity from Covalency: Trends with Oxidation State.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 exchange2024-01-01T00:00:00Z2024 Apr2026-06-01T21:54:26.065Z2025-04-06T03:16:38.541ZS-EPMC110407073866567210.1021/jacsau.4c00213