Valenzdelokalisierte und valenzdefinierte FeII-FeIII-Komplexe: der drastische Einfluß der Liganden

Valence-Delocalized and Valence-Trapped FeIIFeIII Complexes: Drastic Influence of the Ligands

The two macrocyclic ligands H 2 L 1 and H 2 L 2 are not very different, but their Fe II Fe III complexes are remarkably so. [L 1 Fe 2 (μ-OAc) 2 ](ClO 4 ) is valence-delocalized on the Mossbauer time scale over the range 1.8-364 K, whereas [L 2 Fe 2 (μ-OAc)(OAc)(H 2 O)](ClO 4 )·2H 2 O is valence-trapped even at room temperature. The difference in properties of these complexes is also reflected in their electronic spectra, in their electrochemical and magnetic behavior, and in their structures.