Formation of Non-Amphiphilic Vesicles in Organic Solvents

Vesicles are widely utilized in both chemistry and biology; however, most existing vesicular structures are composed of amphiphilic units and form in aqueous solutions. Here, the construction of a novel type of non-amphiphilic vesicle composed of pillar[5]arene derivatives in organic solvents is reported. Cryogenic transmission electron microscopy (Cryo-TEM) and dynamic light scattering (DLS) characterization reveal that these molecules self-assemble into hollow vesicular structures across various solvents. Concentration-dependent experiments in acetonitrile demonstrate that assembly occurs at an exceptionally low concentration threshold (≈2 × 10^-9 m) and remains stable over a broad concentration range (≈2 × 10^-9 m to 4 × 10^-4 m). Furthermore, the vesicles exhibit remarkable stability, persisting for over nine months. Mechanistic studies suggest that their assembly is influenced by the strength of interactions between solvent molecules and pillar[5]arene. Fluorescence measurements further indicate that different solvents modulate the fluorescence intensity of the vesicular assembly, enabling the differentiation of haloalkane isomers.