6-6-closed and 6-5-open isomers of aza- and methanofullerenes probed by steady-state and transient spectroscopy

摘要

[6-5]-open and [6-6]-closed isomers are probed by steady-state and transient absorption spectroscopy. The associated properties lead to the conclusion that in the azafullerene series the nitrogen free electron pair is in resonance with the fullerene pi -system. Complementary MO calculations confirm this assumption. Although the [6-5]-open methanofullerene 4 reveals the best electron accepting properties, its photoinstablity makes it, however, a rather ineffective target molecule for photo-induced electron transfer processes. In contrast, the [6-6]-closed azafullerene 1 is characterized, similar to 3, by a high photostability and, in light of the urrent data, appears to be the most promising monofunctionalized fullerene derivative for electron transfer reactions.