Highly Stable Radical Cations of <i>N</i>,<i>N’</i>‐Diarylated Tetrabenzotetraaza[8]circulene
Yusuke Matsuo, Takayuki Tanaka, Atsuhiro Osuka
Abstract
Abstract N , N ’‐Diarylated tetrabenzotetraaza[8]circulenes 3 a and 3 b were synthesized in good yields by a reaction sequence involving oxidation of tetrabenzodiazadithia[8]circulene 5‐Oct and S N Ar reaction with aniline derivatives. The obtained aza[8]circulenes 3 a and 3 b were easily oxidized to give their radical cations 3 a + and 3 b + , which are highly stable under ambient conditions. X‐ray diffraction analysis of radical cation 3 a + showed a face‐to‐face dimer arrangement with an interplanar separation of 3.320 Å. The spin density of 3 a + was calculated to be delocalized over the whole circulene π‐systems with spin–spin exchange integral ( J =−144 cm −1 ) in the dimeric part. These radical cations displayed far red‐shifted absorption bands reaching to 2000 nm. Thus this study has proved the hetero[8]circulene scaffold to be a new entry of promising electronics and spin materials.