A Functional Model for the Rieske Center: Full Characterization of a Biomimetic N-Ligated [2Fe-2S] Cluster in Different Protonation States

Give and take both: A bis(benzimidazolate)‐capped biomimetic [2Fe‐2S] cluster has been characterized in different protonation states, both in the diferric and mixed‐valent forms. Protonation does not lead to structural changes of the [2Fe‐2S] core, but facilitates its reduction and causes pronounced valence localization in the mixed‐valent state. Concerted proton and electron transfer back to the diferric cluster emulates a key step in the function of mitochondrial Rieske proteins (see scheme).