Intricate Low-Symmetry\nAg<sub>6</sub><b>L</b><sub>4</sub> Capsules Formed by Anion-Templated\nSelf-Assembly of\nthe Stereoisomers of an Unsymmetric Ligand

Metal–organic cages and capsules exhibit space-specific\nfunctions based on their discrete hollow structures. To acquire enzyme-like\nasymmetric or intricate structures, they have been modified by desymmetrization\nwith two or more different ligands. There is a need to establish new\nstrategies that can desymmetrize structures in a simple way using\nonly one type of ligand, which is different from the mixed-ligand\napproach. In this study, a strategy was developed to form interconvertible\nstereoisomers using the unsymmetric macrocyclic ligand benzimidazole[3]arene.\nSingle-crystal X-ray diffraction analysis revealed that the isomers\nassembled with silver tetrafluoroborate afforded a conformationally\nheteroleptic Ag<sub>6</sub><b>L</b><sub>4</sub> capsule with\nan intricate structure. The six Ag ions in the capsule were desymmetrized,\nresulting in significantly different coordination geometries. Remarkably,\nthe capsule encapsulates a single tetrafluoroborate anion via multipoint\nC–H···F–B hydrogen bonds in both the\nsolid and solution states, suggesting that anions of appropriate size\nand shape can act as a template for the capsule formation. These results\ndemonstrate that the use of isomerizable and unsymmetric ligands is\nthe effectiveness of constructing highly dissymmetric supramolecular\nstructures from a single ligand.