Triazasupersumanenes: Bowl-shaped nanographenes with tunable properties and unexpected charge transport performance

Doping heteroatoms into the π-skeleton of buckybowls is a promising strategy for modulating molecular geometry and electronic structures, thereby imparting unique physicochemical properties. In this study, we present the synthesis and characterization of three bowl-shaped nitrogen-doped nanographenes, known as triazasupersumanenes, which feature a coronene core surrounded by alternating five- and six-membered rings. These typical π-bowls display deeper bowl depths, remarkable redshifts in both absorption and emission spectra, and more reversible oxidation peaks compared with their S-doped analog. Furthermore, para-substituents on N-aryls significantly influence molecular properties and exhibit intriguing characteristics, including polar crystals, reversible mechanofluorochromic (MFC) performance, open-shell diradical dication, and supramolecular recognition for fullerene C₆₀. Despite no π⋯π interactions, the fabricated device 1a@CHCl₃ exhibits unexpected p-type transport properties in organic field-effect transistor measurements. This work reveals the structure-property relationships of heterosupersumanenes, offering valuable insights into the design and synthesis of π-bowls with tunable properties and highlighting their potential as organic semiconductors.