Biferrocenium salts with magnetite-like mixed-valence iron: coexistence of Fe3+ and Fe2.5+ in the crystal†
Abstract
The biferrocene-based salt [Bifc]2[Ni(mnt)2]3 (Bifc = bis(isopropylthio)biferrocene; mnt = maleonitriledithiolate) contains a biferrocenium monocation and dication within the same crystal. The coexistence of Fe3+ and mixed-valence Fe2.5+, which resembles the valence state of magnetite, was confirmed by Mössbauer spectroscopy.