Electronic Structure and Properties of Iron-Sulfur Clusters

Iron–sulfur clusters are among the most versatile metalloclusters in nature, serving as the engines of electron transfer, catalysis and regulation in processes ranging from respiration and photosynthesis to nitrogen fixation. These clusters typically comprise two to four iron atoms bridged by sulphur ligands, with oxidation states that can fluctuate between Fe2+ and Fe3+. The interplay between iron d‐orbital occupancy, sulphur–iron covalency and bridging geometry gives rise to rich electronic structures characterised by closely spaced redox levels and multiple spin states. Spectroscopic methods (such as Mössbauer, EPR and UV–Vis spectroscopy) in combination with quantum‐chemical calculations have elucidated charge‐transfer bands arising from sulphur‐to‐iron and iron‐to‐sulphur transitions, while magnetic measurements have revealed antiferromagnetic coupling patterns that stabilise specific total spin states. Recent advances in computational modelling have permitted accurate prediction of redox potentials and excited‐state lifetimes, enabling rational design of biomimetic catalysts. At the frontier of research, single‐molecule techniques and ultrafast spectroscopies are uncovering dynamics of electron transfer on femtosecond timescales, highlighting the role of protein environment in tuning cluster properties. The global significance of this work spans renewable energy conversion, environmental remediation and the development of novel bioinorganic materials.

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Electronic Structure and Properties of Iron-Sulfur Clusters publication trend

The graph below shows the total number of articles in electronic structure and properties of iron-sulfur clusters across all publications each year (not limited to Nature Index journals).

Technical terms

Iron–sulfur cluster: A coordination complex composed of iron and sulphur atoms that forms the active centre in many redox‐active proteins and enzymes.

Charge‐transfer excited state: An electronic state arising when an electron transitions between metal and ligand orbitals, often observed in spectroscopic studies.

Antiferromagnetic coupling: A magnetic interaction in which adjacent iron centres have spins that align oppositely, influencing the overall spin state of the cluster.

Density functional theory: A quantum mechanical modelling method used to investigate the electronic structure of molecular systems.

Configuration interaction: A post‐Hartree–Fock computational technique that accounts for electron correlation by mixing multiple electron configurations.

References

1. Characterization of charge transfer excited states in [2Fe–2S] iron–sulfur clusters using conventional configuration interaction techniques. Theoretical Chemistry Accounts (2020).
2. Interaction Study of Oxygen and Iron‐Sulfur Clusters Based on the Density Functional Theory. International Journal of Chemical Engineering (2022).