德国卡尔斯鲁厄理工学院Roesky, Peter W.团队报道了环状夹层化合物的合成和性质。相关研究成果发表在2023年8月2日出版的国际学术期刊《自然》。

研究人员合成了由单个构建块组装而成的环状纳米级夹层配合物。夹层配合物是有机金属化学的基础，其中一个金属离子被两个平面芳香有机环π配位。它们已成功应用于从催化、合成和电化学到纳米技术、材料科学和医学的广泛应用。扩展夹层结构基序导致线性多decker化合物，其中芳香有机环和金属原子以交替的方式排列。然而，循环多层支架的扩展是前所未有的。

该文中，研究人员展示了一系列环状夹层化合物的设计、合成和表征，其中提出了“环烯”一词。这些环烯由18个重复单元组成，在固态下形成几乎理想的圆形闭环，可以用通式[cyclo-MII(μ-η8:η8-CotTIPS)]18 (M=Sr, Sm, Eu; CotTIPS=1,4-(iPr3Si)2C8H62)来描述。量子化学计算得出的结论是，离子金属与配体的键、配体系统的体积和环闭合的能量增益之间的独特相互作用（主要受分散相互作用的影响）促进了这些环状系统的形成。到目前为止，只有线性一维多层夹层化合物被研究用于可能的应用，如纳米线。这一环状夹层化合物的教科书式例子有望为新功能有机金属材料的进一步创新打开大门。

附：英文原文

Title: Synthesis and properties of cyclic sandwich compounds

Author: Mnzfeld, Luca, Gillhuber, Sebastian, Hauser, Adrian, Lebedkin, Sergei, Hdinger, Pauline, Knfel, Nicolai D., Zovko, Christina, Gamer, Michael T., Weigend, Florian, Kappes, Manfred M., Roesky, Peter W.

Issue&Volume: 2023-08-02

Abstract: Cyclic nanometre-scale sandwich complexes assembled from individual building blocks were synthesized. Sandwich complexes, in which a metal ion is π-coordinated by two planar aromatic organic rings belong to the foundations of organometallic chemistry. They have been successfully used in a wide variety of applications ranging from catalysis, synthesis and electrochemistry to nanotechnology, materials science and medicine1,2. Extending the sandwich structural motif leads to linear multidecker compounds, in which aromatic organic rings and metal atoms are arranged in an alternating fashion. However, the extension to a cyclic multidecker scaffold is unprecedented. Here we show the design, synthesis and characterization of an isomorphous series of circular sandwich compounds, for which the term ‘cyclocenes’ is suggested. These cyclocenes consist of 18 repeating units, forming almost ideally circular, closed rings in the solid state, that can be described by the general formula [cyclo-MII(μ-η8:η8-CotTIPS)]18 (M=Sr, Sm, Eu; CotTIPS=1,4-(iPr3Si)2C8H62). Quantum chemical calculations lead to the conclusion that a unique interplay between the ionic metal-to-ligand bonds, the bulkiness of the ligand system and the energy gain on ring closure, which is crucially influenced by dispersion interactions, facilitate the formation of these cyclic systems. Up to now, only linear one-dimensional multidecker sandwich compounds have been investigated for possible applications such as nanowires3,4,5,6,7,8,9,10. This textbook example of cyclic sandwich compounds is expected to open the door for further innovations towards new functional organometallic materials.

DOI: 10.1038/s41586-023-06192-4

Source: https://www.nature.com/articles/s41586-023-06192-4