Work

Azulene in a Bowl: A Nonalternant Buckybowl With 5/7 Topology, Azulene‐Derived Properties, and Fullerene Complexation

Year: 2025

Type: article

Abstract: ABSTRACT Despite the intriguing potential of azulene‐embedded nanocarbons, their integration into curved buckybowl architectures has remained unexplored due to synthetic and stability challenges. Herein, we report an azulene‐containing buckybowl 6 , synthesized via a concise four‐step route where the azulene core remains stable without rearrangement to naphthalene. Single‐crystal X‐ray analysis revealed that 6 adopts a nonalternant, bowl‐shaped geometric configuration. Unlike classical buckybowls (e.g., corannulene, dibenzo[a,g]corannulene, and summane), 6 exhibits distinct azulene‐derived properties: red‐shifted UV‐vis absorption, anti‐Kasha photoluminescence, and reversible proton‐responsive behavior. Theoretical studies reveal unique aromaticity in its central pentagon, diverging from known pentagon‐containing buckybowls. Furthermore, it was found that buckybowl 6 can assemble with fullerene C 60 or C 70 in a 1:1 stoichiometry. This work establishes 6 as the unique azulene‐based buckybowl and pioneers a design strategy for nonalternant, positively curved π‐systems with 5/7 ring topologies and tunable optoelectronic properties.

Source: Chemistry - A European Journal

DOI: 10.1002/chem.202503258