Metal–organic polyhedra featuring non-Archimedean/Platonic architectures with multiple kinds of vertices have aroused great attention for their fascinating structures and properties but are yet challenging to achieve. Here, we report a combinatorial strategy to make such nonclassic polyhedral cages by combining kinetically labile metal ions with non-planar organic linkers instead of the usual only inert metal centers and planar ligands. This facilitates the synthesis of an enantiopure twisted tetra(3-pyridyl)-based TADDOL (TADDOL = tetraaryl-1,3-dioxolane-4,5-dimethanol) ligand (L) capable of binding Ni(II) ions to produce a regular convex cage, Ni₆L₈, with two mixed metal/organic vertices and three rarely reported concave cages Ni₁₄L₈, Ni₁₈L₁₂, and Ni₂₄L₁₆ with three or four mixed vertices. Each of the cages has an amphiphilic cavity decorated with chiral dihydroxyl functionalities and packs into a three-dimensional structure. The enantioselective adsorption and separation performances of the cages are strongly dependent on their pore structure features. Particularly, Ni₁₄L₈ and Ni₁₈L₁₂ with wide openings can be solid adsorbents for the adsorptive and solid-phase extractive separation of a variety of racemic spirodiols with up to 98% ee, whereas Ni₆L₈ and Ni₂₄L₁₆ with smaller pore apertures cannot adsorb the racemates. The combination of single-crystal X-ray diffraction analysis of the host–guest adduct and GCMC simulation indicates that the enantiospecific recognition capabilities originate from the well-organized chiral inner sphere as well as multiple interactions within the chiral microenvironment. This work therefore provides an attractive strategy for the rational design of polyhedral cages, showing geometrically fascinating structures with properties different from those of classic assemblies.

中文翻译：

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单手性多孔金属-具有多种顶点的有机多面体

具有多种顶点的非阿基米德/柏拉图结构的金属有机多面体因其迷人的结构和特性而引起了极大的关注，但实现起来仍具有挑战性。在这里，我们报告了一种组合策略，通过将动力学不稳定的金属离子与非平面有机连接基结合，而不是通常只有惰性金属中心和平面配体，来制造这种非经典多面体笼。这有助于合成对映体纯扭曲四（3-吡啶基）基 TADDOL（TADDOL = tetraaryl-1,3-dioxolane-4,5-dimethanol）配体（L）能够结合 Ni（II）离子以产生常规凸笼，Ni ₆ L ₈，具有两个混合金属/有机顶点和三个很少报道的凹笼 Ni ₁₄L ₈、Ni ₁₈ L ₁₂和 Ni ₂₄ L ₁₆具有三个或四个混合顶点。每个笼子都有一个装饰有手性二羟基官能团的两亲空腔，并堆积成三维结构。笼的对映选择性吸附和分离性能在很大程度上取决于它们的孔结构特征。特别是，具有大开口的 Ni ₁₄ L ₈和 Ni ₁₈ L ₁₂可以作为固体吸附剂吸附和固相萃取分离多种外消旋螺二醇，其 ee 高达 98%，而 Ni ₆ L ₈和 Ni ₂₄孔径较小的L _{16不能吸附外消旋体。}主客体加合物的单晶 X 射线衍射分析和 GCMC 模拟的结合表明，对映特异性识别能力源自组织良好的手性内球以及手性微环境内的多重相互作用。因此，这项工作为多面体笼的合理设计提供了一种有吸引力的策略，展示了具有不同于经典组件的特性的几何迷人结构。