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Updated: Aug 13, 2025
Author Spotlight: Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
An Open-Cuboidal [Fe3S4] Cluster Characterized in Both Biologically Relevant Redox States
Alexandra C Brown1, Daniel L M Suess1
1Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
Abstract:
Synthetic analogues of the three common types of Fe-S clusters found in biology─diamond-core [Fe2S2] clusters, open-cuboidal [Fe3S4] clusters, and cuboidal [Fe4S4] clusters─have been reported in each biologically relevant redox state with one exception: the open-cuboidal [Fe3S4]+ cluster. Here, we describe the synthesis and characterization of an open-cuboidal [Fe3S4] cluster in both biologically relevant redox states: [Fe3S4]+ and [Fe3S4]0. Like their biological counterparts, the oxidized cluster has a spin-canted, S = 1/2 ground state, and the reduced cluster has an S = 2 ground state. Structural analysis reveals that the [Fe3S4] core undergoes substantial contraction upon oxidation, in contrast to the minimal structural changes observed for the only [Fe3S4] protein for which high-resolution structures are available in both redox states (Azotobacter vinelandii ferredoxin I; Av FdI). This difference between the synthetic models and Av FdI is discussed in the context of electron transfer by [Fe3S4] proteins.
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