It is widely known that the skeletal structure of clusters reflects the number of skeletal bonding electron pairs involved, which is called the polyhedral skeletal electron pair theory (PSEPT) or Wade and Mingos rules. While recent computational studies propose that the increase of skeletal electrons of polyhedral clusters leads to the flat structure beyond the PSEPT, little experimental evidence has been demonstrated. Herein, we report the synthesis of a C₂B₄R₄ carborane 2 featuring a flat ribbon-like structure. The C₂B₄ core of 2 bearing 16 skeletal electrons in the singlet-ground state defies both the [4n + 2] Hückel’s rule and Baird’s rule. Nevertheless, the delocalization of those electrons simultaneously induces two independent π- and two independent σ-aromatic ring currents, rendering quadruple aromaticity.

众所周知，簇的骨架结构反映了所涉及的骨架键合电子对的数量，这称为多面体骨架电子对理论（PSEPT）或Wade and Mingos规则。尽管最近的计算研究表明多面体簇的骨架电子的增加导致了超出PSEPT的平面结构，但几乎没有实验证据。在此，我们报道了具有扁平带状结构的C ₂ B ₄ R ₄碳硼烷2的合成。在单重态下，具有16个骨架电子的2的C ₂ B ₄核对[4 n + 2]Hückel法则和Baird法则。然而，这些电子的离域同时引发了两个独立的π-和两个独立的σ-芳族环电流，从而提供了四倍的芳香性。