Intramolecular Electron Transfer in Mixed-Valence Biferrocenium Salts Containing Heteroatoms:  Preparation, Structure, and⁵⁷Fe Mössbauer Characteristics

Abstract

A convenient new method is developed for the preparation of 1‘,1‘‘‘-disubstituted biferrocenes which can be oxidized with iodine to a new series of mixed-valence compounds. The X-ray structures of 1‘,1‘‘‘-dimethoxymethyl, 1‘,1‘‘‘-diethoxyl, 1‘,1‘‘‘-dimethyl, 1‘,1‘‘‘-dihydroxymethyl, 1‘,1‘‘‘-dibenzoyloxymethyl, 1‘,1‘‘‘-dimethylthio, and 1‘,1‘‘‘-diethylthio neutral biferrocenes and the mixed-valence 1‘,1‘‘‘-diethoxyl, 1‘,1‘‘‘-dimethyl, 1‘,1‘‘‘-dibenzoyloxymethyl, and 1‘,1‘‘‘-diphenylthio biferrocenium triiodide salts have been determined at 298 K. The rates of intramolecular electron transfer in these mixed-valence cations were estimated by variable-temperature 57 Fe Mössbauer experiment.