Linear Non-benzenoid Isomer of Acene Fusing Chrysene with Azulene Units

Non-benzenoid polycyclic aromatic hydrocarbons (PAHs)
have received
considerable attention owing to their distinctive optical and electrical
properties. Nevertheless, the synthesis and optoelectronic application
of non-benzenoid PAHs remain challenging. Herein, we present a facile
synthesis of linear non-benzenoid PAH with an armchair edge, diACh, by fusing chrysene with two azulene units. We systematically
investigated the optical and electrical properties, which were also
compared to its isomers, including benzenoid and non-benzenoid zigzag
edge isomers. diACh exhibits global aromaticity, good
planarity, and suitable highest occupied molecular orbital/lowest
unoccupied molecular orbital energy levels. The protonation of diACh in solution successively forms a stable tropylium cation
and dication. Moreover, the neutral, cationic, and dicationic states
of diACh can be transformed with remarkable reversibility
during the protonation–deprotonation process, as confirmed
by ultraviolet–visible absorptions, fluorescence spectra, 1H nuclear magnetic resonance, and theoretical calculations.
Additionally, we fabricate p-type organic field-effect transistor
(OFET) devices based on diACh with hole mobility up to
0.026 cm2 V–1 s–1,
and we further develop OFET-based acid vapor sensors with good sensitivity,
recyclability, and selectivity. These findings underscore the unique
properties of linear non-benzenoid PAHs with an armchair edge engendered
by the fusion of azulene with the acene backbone, showcasing prospective
applications in organic optoelectronics.