上海科技大学知识管理系统

Coronoids as polycyclic aromatic macrocycles enclosing a cavity have attracted a lot of attention due to their distinctive molecular and electronic structures. They can be also regarded as nanoporous graphene molecules, whose electronic properties are critically dependent on the size and topology of both outer and inner peripheries. However, due to the challenge of synthesis, the extended hexagonal coronoids with zigzag outer edges have not been reported yet. Here, we report the on-surface synthesis of C144 hexagonal coronoid with outer zigzag edges upon designed precursor undergoing the hierarchical Ullmann coupling and cyclodehydrogenation on Au(111) surface. The molecular structure is unambiguously characterized by bond-resolved non-contact atomic force microscopy imaging. The electronic properties are further investigated by scanning tunneling spectroscopy measurements, incombination with the density functional theory calculations. Moreover, the values of harmonic oscillator model of aromaticity (HOMA) are derived from calculations, which suggest that the molecular structure is ideally represented by Clar’s model. Our results provide approaches on realizing hexagonal coronoid with zigzag edges, potentially inspiring on fabricating the hexagonal zigzag coronoid with multiple radical characters in future.