Vibrational Architecture of [Fe₄S₄]0/1+/2+/3+/4+ Iron–Sulfur Cubanes

We herein present a comprehensive analysis of the oxidation-state-dependence of the 57Fe partial vibrational density of states (PVDOS), measured using nuclear resonance vibrational spectroscopy (NRVS), across a complete oxidation state series of iron-sulfur cubane (Fe4S4) clusters, which covers the [Fe4S4]0/1+/2+/3+/4+ redox levels. It is thereby revealed that the electronic/magnetic (and the thereof resulting geometric) symmetry of the respective complexes imprints onto their vibrational architecture, providing a rare experimental insight into the elusive relationship between these fundamental attributes. Modeling of our results at the broken-symmetry (BS) density functional theory (DFT) level allowed rationalizing the observed trends and supports the empirical correlations.