Study of intervalence bands due to reversible intramolecular electron transfer phenomena in purely organic mixed-valence high-spin molecules

Up to now, few examples of reversible electron intramolecular transfer phenomena in purely organic mixed-valence molecules have been studied in detail. We present the first example of a purely organic molecule in which, in addition to the observation of an optical electron transfer between open-shell and anionic sites, two radical centers remain ferromagnetic ally coupled inside the molecule. The intervalence band which arises from the optical ET is clearly observed in the far NIR range and is quantitatively analyzed by means of an ad hoc model. Since these properties are rather unusual for purely organic compounds, even separately, this and similar molecules offer us a unique chance for studying the reciprocal influence between electron transfer and strong magnetic coupling in organic systems.