Mixed-valence state of optically active 1 ',1 '''-bis(2-phenylbutyl)-1,1 ''-biferrocenium pentalodide: Effects of cation symmetry and intermolecular interaction on trapped-/detrapped-valence states

摘要

The effects of cation symmetry and packing on the mixed-valence state of binuclear ferrocene derivatives are discussed separately by using chiral isomers and racemic modification of 1',l"'-bis(2-phenylbutyl)-1,1"-biferrocenium pentaiodide. The pentaodide anion has a polymeric structure and is composed of triiodide anion and iodine molecule units. The (R,S) isomer having an inversion center shows a detrapped-valence state even at 78 K. On the other hand, the (R,R) and the (S,S) isomers having no inversion center show a trapped-valence state at room temperature. The racemic modification, however, consisting of the (R,R) and the (S,S) isomers shows a perfect detrapped-valence state at room temperature. This finding shows that the packing effect overcomes the effect of cation asymmetry. [References: 31]