Triazatruxene radical cation: a trigonal class III mixed valence system

Abstract

The highly symmetric and stable triazatruxene radical cation was generated chemically for the first time. The intervalence charge transfer (IV-CT) absorption band of the radical cation was observed at 7500–12 500 cm⁻¹. The IV-CT band exhibited a well-resolved, solvent independent vibrational structure which prompted us to classify the radical cation as a Robin and Day class III IV-CT compound. The assignment was examined in light of two previously reported semi-classical models for three-center IV-CT systems. The triazatruxene radical cation is the first and only example of a three-center class III IV-CT system.