Twisted pentagonal prisms: AgnL2 metal-organic pillars

Abstract

<h2>Summary</h2> The structures of hierarchically assembled supramolecular architectures are dictated characteristically by the encoded symmetries and geometries of the corresponding building blocks. In literature, assorted Platonic molecular polyhedra have been built out of highly symmetric macrocycles. Nonetheless, the synthesis of pillararene-based molecular cages remains challenging owing to the underlying shape and limited derivatization strategies of this macrocyclic scaffold. Herein, we report the assembly of Ag_nL₂ metal-organic pillars from rim-differentiated pillar[5]arene-derived ligands, <b>L</b>_m and <b>L</b>_p, through [N···Ag⁺···N] coordinative bonds. These stereolabile macrocycles undergo chiral self-sorting during complexation. Although the <i>meta</i>-substituted <b>L</b>_m forms diastereoisomeric Ag₅<b>L</b>_m2 complexes without stereocontrol in solution, only a <i>meso</i>-Ag₄<b>L</b>_m2 complex with a Ag₄ kernel was observed in the solid state. In contrast, the narcissistic coassembly of the <i>para</i>-substituted <b>L</b>_p with AgPF₆ results in enantiomeric Ag₅<b>L</b>_p2 complexes resembling twisted pentagonal prisms. This research paves the way for the construction of deep-cavity metallocavitands and nanochannels with unique molecular recognition and transportation properties.