Tetrabenzo[a,f,j,o]perylene: A Polycyclic Aromatic Hydrocarbon with An Open-Shell Singlet Biradical Ground State

Abstract

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. A novel tetrabenzo[a,f,j,o]perylene, namely "bistetracene" in which two tetracenes are connected side by side with two bonds, was synthesized and characterized. An optical energy gap of about 1.56eV is derived from the UV/Vis absorption spectrum, showing the low optical gap feature of such zigzag-edged polycyclic aromatic hydrocarbons (PAHs). Theoretical calculations and physical property investigations manifest that such a PAH possesses a prominent biradical character in the ground state, which is the first example among bistetracene derivatives. However, the bistetracene can easily undergo oxidation to tetrabenzo[a,f,j,o]perylene-9,19-dione (diketone) under ambient conditions. Thereby, such zigzag-edged PAH provides insight into understanding the edge state of other expanded homologues, such as peri-tetracenes or peri-pentacenes.