Anhui Province Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009, P. R. China.
State Key Laboratory for Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, P. R. China.
J Am Chem Soc. 2021 Aug 18;143(32):12560-12566. doi: 10.1021/jacs.1c03652. Epub 2021 Aug 3.
It is extremely difficult to anticipate the structure and the stereochemistry of a complex, particularly when the ligand is flexible and the metal node adopts diverse coordination numbers. When trivalent lanthanides (Ln) and enantiopure amino acid ligands are utilized as building blocks, self-assembly sometimes yields rare chiral polynuclear structures. In this study, an enantiopure carboxyl-functionalized amino acid-based ligand with symmetry reacts with lanthanum cations to give a homochiral porous coordination cage, (Δ/Λ)-. The dodecanuclear lanthanide cage has an unprecedented octahedral "cage-in-cage" framework. During the self-assembly, the chirality is transferred from the enantiopure ligand and fixed by the binuclear lanthanide cluster to give 12 metal centers that have either Δ or Λ homochiral stereochemistry. The cage exhibits excellent enantioselective separation of racemic alcohols, 2,3-dihydroquinazolinones, and multiple commercially available drugs. This finding exhibits a rare example of a multinuclear lanthanide complex with a dual-walled topology and homochirality. The highly ordered self-assembly and self-sorting of flexible amino acids and lanthanides shed light on the chiral transformation between different complicated artificial systems that mimic natural enzymes.
当使用三价镧系元素（Ln）和手性氨基酸配体作为构建块时，自组装有时会产生罕见的手性多核结构。在这项研究中，一种具有 对称的手性羧酸官能化氨基酸基配体与镧离子反应，生成同手性多孔配位笼（Δ/Λ）-。这个十二核镧系元素笼具有前所未有的八面体“笼中笼”骨架。在自组装过程中，手性从手性纯配体转移并被双核镧系元素簇固定，从而赋予 12 个金属中心具有Δ或Λ同手性立体化学。该笼对外消旋醇、2,3-二氢喹唑啉酮和多种市售药物具有优异的对映选择性分离性能。这一发现展示了具有双重壁拓扑和同手性的多核镧系元素配合物的罕见实例。柔性氨基酸和镧系元素的高度有序自组装和自分类揭示了模拟天然酶的不同复杂人工系统之间手性转变的机制。
