γ-Graphyne is an emerging carbon allotrope, and synthesis of large-size atomically precise γ-graphyne fragments would be crucial to understand its distinctive properties. Herein, a long-sought-after graphyne spoked wheel with 6-fold symmetry was synthesized mainly through cobalt(0)-catalyzed cyclotrimerization of a triyne intermediate followed by 12-fold intramolecular Stille coupling reactions. Its structure was unambiguously confirmed by X-ray crystallographic analysis, which revealed a closely stacked dimer structure. NMR and theoretical analysis disclosed that fusion of six anti-aromatic hexadehydro[12]annulene units led to a decrease in local aromaticity of all seven benzenoid rings (particularly, the central one), which is quite different from a graphene analog, hexa-peri-hexabenzocoronene (HBC). Its optical and electrochemical properties are also different from those of HBC, showing allowed HOMO → LUMO electronic transition and facile electrochemical reduction. This study provided a new method for the synthesis of even larger γ-graphyne fragments and demonstrated the unique electronic properties and packing structure of γ-graphyne as compared with those of graphene.

γ-石墨烯是一种新兴的碳同素异形体，大尺寸原子级精确的γ-石墨烯碎片的合成对于理解其独特的特性至关重要。在此，主要通过钴（0）催化的三炔中间体环三聚化，然后进行 12 倍分子内 Stille 偶联反应，合成了备受追捧的具有 6 倍对称性的石墨炔辐条轮。X 射线晶体学分析明确证实了其结构，该分析揭示了紧密堆叠的二聚体结构。核磁共振和理论分析表明，六个反芳香族六氢[12]环烯单元的融合导致所有七个苯环（特别是中心环）的局部芳香性降低，这与石墨烯类似物六边形有很大不同。-六苯并晕烯 (HBC)。其光学和电化学性质也不同于HBC，表现出允许的HOMO→LUMO电子跃迁和容易的电化学还原。该研究为合成更大的γ-石墨烯碎片提供了一种新方法，并证明了γ-石墨烯与石墨烯相比具有独特的电子特性和堆积结构。