Cascade Assembly of Pillar[5]arene-Based Supramolecules Formed by Hexahydrogen Bonding and Host-Guest Interactions

Supramolecular aggregates constructed through multiple noncovalent interactions have garnered significant attention across various fields due to their modular and controllable assembly methods. In this study, we introduce a novel approach to modulate the hydrophilicity and hydrophobicity of supramolecular systems by incorporating structurally diverse molecules through hexahydrogen bonding interactions in a polar solvent. To investigate the synergistic effects of host-guest interactions and hydrogen bonding on the formation of supramolecular aggregates, molecules of Hamilton wedge-functionalized pillar[5]arene (H₁), barbituric acid derivatives with hydrophilic or hydrophobic chains (C_1-2), and a guest molecule (G) featuring a tetraphenylethylene (TPE) core were designed and synthesized. Two types of supramolecular aggregates, H₁C₁G and H₁C₂G, were constructed via orthogonal two-step assembly, resulting in a diverse range of molecular aggregate morphologies in both nonpolar and polar solvents. Ordered nanosheets and vesicle structures were displayed by aggregate H₁C₁G with a hydrophobic chain and aggregate H₁C₂G with a hydrophilic chain, through hydrophilic/hydrophobic and π-π stacking interactions. Interestingly, toxic environmental pollutants such as succinonitrile, hexanedinitrile, and methylviologen were effectively detected by fluorescent probe H₁C₁G with high sensitivity and selectivity. Furthermore, the coassemblies of H₁C₂G and Nile red exhibit FRET effects and are sensitive to acid, enabling acid-sensitive information encryption. The findings of this study offer new insights into the facile construction of functionalized supramolecular aggregates with various morphologies for practical applications of supramolecular soft materials.