Moessbauer spectroscopic studies on mixed-valence states in trinuclear iron carboxylates

Mixed-valence states of iron atoms in newly synthesized mixed-valence trinuclear iron carboxylate complexes with π-bonding ligands, such as acrylate, diphenylacetate, 1-naphthylacetate, and cyclohexylacetate which has no π-bonding, were studied by means of Moessbauer spectroscopy. The cyclohexylacetate complex shows a temperature-dependent valence delocalization, while the 1-naphthylacetate complex shows temperature-independent mixed-valence states. The acrylate and diphenylacetate complexes show temperature-dependent mixed-valence states, although they do not reach an averaged-valence state at room temperature. (orig.)