Iron-57 Mössbauer spectroscopic and X-ray diffraction studies on the mixed-valence state of binuclear ferrocene derivatives with long alkyl substituents

Abstract

The mixed-valence states of biferrocene derivatives with long alkyl substituents, which have a layered structure, have been investigated by means of ⁵⁷Fe Mössbauer spectroscopy and X-ray powder diffraction. An interesting even–odd character in the number of carbon atoms of the alkyl chain is found in the relationship between the crystal structure and the mixed-valence state. The mixed-valence states of 1′,1‴-bis(dodecyl)-1,1″-biferrocenium triiodide change in accordance with a transformation of the crystal structure in the solid state. An X-ray diffraction analysis for this salt obtained from dichloromethane at 0 °C showed that both the cation and the anion are situated at a centre of symmetry and the dodecyl substituent has the all-trans conformation. The layers are located in the ab plane.