Pyrrole-Fused Azacoronenes with Various Redox States
The synthesis was successively performed by SNAr reaction with fluoroiodobenzenes, Suzuki-Miyaura coupling, and oxidative Scholl reaction. As characteristic features, cyclic voltammograms exhibit up to three reversible oxidation peaks having similar first two oxidation potentials and differences between second and third oxidation potentials become smaller in order of decreasing the number of pyrroles. Chemical oxidations by monitoring the absorption spectra revealed that these compounds had different electronic states in their oxidation states. Recently, we have further designed and synthesized a new family that has two carbonyl groups directly introduced to the π-system. It is expected that the resonance forms observed for the oxidation states of previous azacoronenes become possible in the neutral state. As the result, new ones exhibit significantly different physical properties.
In the presentation, synthesis and optical and electronic properties of azacoronenes will be discussed.