Azulene-Fused <i>seco</i>-Hexabenzocoronene-Based Nanographenes

Due to the unique electronic structure, azulene-containing polycyclic aromatic hydrocarbons attract significant attention toward tuning the chemical and electronic properties of benzenoid carbocyclic systems. Here, we report the synthesis and properties of two types of azulene fused, <i>seco</i>-hexabenzocoronene-based nanographenes. The X-ray crystallographic analysis indicated their nonplanar structures with highly torsional periphery in the solid structures. The typical narrow highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) energy gaps, long-wavelength absorption, and <i>anti</i>-Kasha emissions were investigated by experimental and computational studies. Interestingly, these nanographenes exhibited a pronounced photothermal effect.