1,3,5–2,4,6‐Functionalized Benzene Molecular Cage: An Environmentally Responsive Scaffold that Supports Hierarchical Superstructures
Xin‐Yu Pang, Hang Zhou, Xiaojiang Xie, Wei Jiang, Yinhua Yang, Jonathan L. Sessler, Han‐Yuan Gong
Abstract
Abstract New stimulus‐responsive scaffolds are of interest as constituents of hierarchical supramolecular ensembles. 1,3,5–2,4,6‐Functionalized, facially segregated benzene moieties have a time‐honored role as building blocks for host molecules. However, their user as switchable motifs in the construction of multi‐component supramolecular structures remains poorly explored. Here, we report a molecular cage 1 , which consists of a bent anthracene dimer 3 paired with 1,3,5‐tris(aminomethyl)‐2,4,6‐triethylbenzene 2 . As the result of the pH‐induced ababab ↔ bababa isomerization of the constituent‐functionalized benzene units derived from 2 , this cage can reversibly convert between an open state and a closed form, both in solution and in the solid state. Cage 1 was used to create stimuli‐responsive hierarchical superstructures, namely Russian doll‐like complexes with [K⊂18‐crown‐6⊂ 1 ] + and [K⊂cryptand‐222⊂ 1 ] + . The reversible assembly and disassembly of these superstructures could be induced by switching cage 1 from its open to closed form. The present study thus provides an unusual example where pH‐triggered conformation motion within a cage‐like scaffold is used to control the formation and disassociation of hierarchical ensembles.