Valence detrapping in mixed-Valence biferrocenes : evidence for phase transitions

The preparation and physical data characterizing valence detrapping for the PF 6 - and SbF 6 - salts of the mixed-valence dichlorobiferrocenium, 1',1'''-dihromohiferrocenium, and 1', 1'''-diiodohiferrocenium cations are presented. All six compounds are shown to he valence trapped on the vibrational time scale as indicated by C-H bending bands seen in the 815-85-cm -1 region of the IR spectrum