Synthesis and Characterization of Dibenzo[hi,st]ovalene as a Highly Fluorescent Polycyclic Aromatic Hydrocarbon and Its π-Extension to Circumpyrene

Abstract

Polycyclic aromatic hydrocarbons (PAHs) with zigzag edges have attracted increasing attention for their unique optical and electronic properties. This account describes our synthetic approaches to dibenzo[hi,st]ovalene (DBOV) as a novel PAH with a combination of armchair and zigzag edges and the elucidation of its unique optoelectronic and photophysical properties, such as strong red emission with a fluorescence quantum yield of up to 0.89 and stimulated emission. Furthermore, DBOV demonstrated the so-called fluorescence blinking that enables its application as a fluorophore in single-molecule localization microscopy, which is one of the modern superresolution fluorescence microscopy methods. The self-assembly of a DBOV derivative bearing two 3,4,5-tris(dodecyloxy)phenyl groups was also investigated, showing the formation of helical columnar stacks. On the other hand, the regioselective bromination of DBOV was achieved, allowing the postsynthetic functionalization and modulation of the optoelectronic properties. Moreover, π-extension of the DBOV at the bay regions led to circumpyrene, the largest circumarene synthesized to date.