Pausch Tobias, Martínez Mestre Pablo, Zapata Fabiola, Mix Andreas, Schmidt Bernd M
Institut für Organische Chemie und Makromolekulare Chemie, Heinrich-Heine-Universität Düsseldorf Universitätsstraße 1 Düsseldorf 40225 Germany
Departamento de Química Orgánica, Universidad de Murcia Edificio 19 Murcia 30100 Spain.
Chem Sci. 2025 Jun 18. doi: 10.1039/d5sc02247a.
Dynamic covalent chemistry is a powerful tool to synthesise complex structures from simple building blocks. However, even minor variations in the numerous parameters governing self-assembly can drastically influence the size and structure of the resulting assemblies. Herein, we report the selective formation of three cages belonging to the low-symmetry Tri Tri cage topology for the first time, using highly symmetric tritopic building blocks, confirmed by single-crystal X-ray (SC-XRD) analysis. Fluorinated and non-fluorinated aldehydes were combined with two amines differing in their degree of structural flexibility. Applying either kinetic or thermodynamic control through solvent selection allowed for the selective synthesis of either the low-symmetry Tri Tri or the larger, highly symmetric TriTri assemblies. While the fluorinated linker strongly preferred the formation of the Tri Tri cage topology under thermodynamic control, the non-fluorinated linker selectively formed the TriTri species. Kinetic control, using methanol as a poor solvent, allowed for the selective precipitation of the Tri Tri intermediate. Reduction of the Janus-like fluorinated Tri Tri cages yielded the cages EtF and TRENF , which showed high potential for removing perfluorooctanoic acid (PFOA) from water, with EtF exhibiting structural rearrangements in organic solvents to accommodate PFOA, as observed by H and F NMR titrations in combination with F DOSY measurements.
动态共价化学是一种从简单构建单元合成复杂结构的强大工具。然而，在控制自组装的众多参数中，即使是微小的变化也会极大地影响所得组装体的尺寸和结构。在此，我们首次报道了使用高度对称的三官能团构建单元选择性地形成三种属于低对称性三三笼拓扑结构的笼状化合物，并通过单晶X射线（SC-XRD）分析得以证实。将氟化和非氟化醛与结构柔性程度不同的两种胺相结合。通过溶剂选择应用动力学或热力学控制，能够选择性地合成低对称性的三三笼状化合物或更大的、高度对称的TriTri组装体。在热力学控制下，氟化连接基强烈倾向于形成三三笼拓扑结构，而非氟化连接基则选择性地形成TriTri物种。以甲醇作为不良溶剂进行动力学控制，可以使三三中间体选择性沉淀。对类Janus氟化三三笼进行还原得到笼状化合物EtF和TRENF，它们在从水中去除全氟辛酸（PFOA）方面显示出很高的潜力，正如通过氢和氟核磁共振滴定结合氟扩散有序光谱（F DOSY）测量所观察到的，EtF在有机溶剂中会发生结构重排以容纳PFOA。
