Pillar[6]arene Assemblies With Continuous Hydrophobic Grooves for Capture of π-Conjugated Molecules

Preorganization is a central principle in supramolecular chemistry, enabling selective molecular recognition through confined macrocyclic cavities. Extending this concept from single macrocycles to their assemblies could enable recognition beyond single-cavity limits. However, it remains unclear how molecular assemblies can be rationally designed to generate collective binding environments and how selective molecular recognition can emerge without well-defined confinement. Herein, we report a hierarchical assembly comprising a bridge-functionalized amphiphilic pillar[6]arene that enables selective molecular recognition. Hexagonal pillar[6]arenes first assemble into tubular structures, which further stack into sheets in water, generating continuous hydrophobic grooves between adjacent tube surfaces. These grooves enable selective capture of aromatic hydrocarbons that cannot be accommodated within the intrinsic cavity of pillar[6]arene. The recognition selectivity is governed by a balance between guest surface area and water solubility, allowing efficient separation of structurally similar isomers such as phenanthrene and anthracene. Beyond small hydrocarbons, the use of mechanical grinding allows unsubstituted π-conjugated polymers, which are generally insoluble in common solvents including water, to be dispersed in water through incorporation within the grooves. Therefore, in the present study we constructed pillar[6]arene assemblies that are capable of external recognition and provide a means of extending host-guest chemistry beyond individual building blocks.