The singlet states of cyclopentadienyl (Cp) cations are considered as true prototypes of an antiaromatic system. Unfortunately, their high intrinsic reactivity inhibited their isolation in the solid state as a salt, and controlled reactions are also scarce. Here we present the synthesis and solid state structure of the room-temperature-stable Cp cation salt [Cp(C₆F₅)₅]⁺[Sb₃F₁₆]⁻. Although the aromatic triplet state of the [Cp(C₆F₅)₅]⁺ cation is energetically favoured in the gas phase according to quantum chemical calculations, coordination of the cation by either [Sb₃F₁₆]⁻ or C₆F₆ in the crystal lattice stabilizes the antiaromatic singlet state, which is present in the solid state. The calculated hydride and fluoride ion affinities of the [Cp(C₆F₅)₅]⁺ cation are higher than those of the perfluorinated tritylium cation [C(C₆F₅)₃]⁺. Reactions of [Cp(C₆F₅)₅]⁺[Sb₃F₁₆]⁻ with CO, which probably yields the corresponding carbonyl complex, and of radical Cp(C₆F₅)₅∙ with selected model substrates (Cp₂Fe, (Ph₃C∙)₂ and Cp*Al) are also presented.

环戊二烯基 (Cp) 阳离子的单线态被认为是反芳香系统的真实原型。不幸的是，它们的高固有反应性抑制了它们以盐的形式在固态下的分离，并且受控反应也很少。在这里，我们介绍了室温稳定的 Cp 阳离子盐 [Cp(C ₆ F ₅ ) ₅ ] ⁺ [Sb ₃ F ₁₆ ] ^-的合成和固态结构。尽管根据量子化学计算，[Cp(C ₆ F ₅ ) ₅ ] ⁺阳离子的芳香族三重态在气相中是有利的，但阳离子通过 [Sb ₃ F ₁₆ ] ^-或 C ₆ F ₆进行配位晶格中稳定了固态中存在的反芳香族单线态。计算得出的[Cp(C ₆ F ₅ ) ₅ ] ⁺阳离子的氢化物和氟离子亲和力高于全氟化三苯蒂阳离子[C(C ₆ F ₅ ) ₃ ] ⁺的氢化物和氟离子亲和力。 [Cp(C ₆ F ₅ ) ₅ ] ⁺ [Sb ₃ F ₁₆ ] ⁻与 CO 的反应，可能会产生相应的羰基络合物，以及自由基 Cp(C ₆ F ₅ ) ₅ ∙ 与选定的模型底物 (Cp ₂还提出了 Fe、(Ph ₃ C∙) ₂和 Cp*Al)。