Schulte Yannick, Wölper Christoph, Rupf Susanne M, Malischewski Moritz, SantaLucia Daniel J, Neese Frank, Haberhauer Gebhard, Schulz Stephan
Institute of Inorganic Chemistry, University of Duisburg-Essen, Essen, Germany.
Institute of Inorganic Chemistry, Freie Universität Berlin, Berlin, Germany.
Nat Chem. 2024 Apr;16(4):651-657. doi: 10.1038/s41557-023-01417-5. Epub 2024 Jan 15.
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(CF)][SbF]. Although the aromatic triplet state of the [Cp(CF)] cation is energetically favoured in the gas phase according to quantum chemical calculations, coordination of the cation by either [SbF] or CF 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(CF)] cation are higher than those of the perfluorinated tritylium cation [C(CF)]. Reactions of [Cp(CF)][SbF] with CO, which probably yields the corresponding carbonyl complex, and of radical Cp(CF)∙ with selected model substrates (CpFe, (PhC∙) and Cp*Al) are also presented.
环戊二烯基（Cp）阳离子的单重态被认为是反芳香体系的真正原型。不幸的是，它们极高的固有反应活性阻碍了其以盐的形式在固态下被分离出来，而且可控反应也很稀少。在此，我们展示了室温稳定的Cp阳离子盐[Cp(CF)][SbF]的合成及其固态结构。尽管根据量子化学计算，[Cp(CF)]阳离子的芳香三重态在气相中能量上更有利，但在晶格中[Cp(CF)]阳离子与[SbF]或CF的配位作用稳定了固态中存在的反芳香单重态。计算得出的[Cp(CF)]阳离子的氢化物和氟离子亲和力高于全氟三苯甲基阳离子[C(CF)]。本文还介绍了[Cp(CF)][SbF]与CO的反应（可能生成相应的羰基配合物）以及自由基Cp(CF)∙与选定模型底物（CpFe、(PhC∙)和Cp*Al）的反应。
