Size‐Control by Anion Templating in Mechanochemical Synthesis of Hemicucurbiturils in the Solid State

Solid chemistry: The acid‐catalyzed synthesis of hemicucurbiturils proceeds quantitatively in the solid state. Mechanochemically obtained mixtures of solid oligomers spontaneously and selectively rearrange into either six‐ or eight‐membered macrocycles in the presence of suitable anion templates.

Abstract

Self‐organization is one of the most intriguing phenomena of chemical matter. While the self‐assembly of macrocycles and cages in dilute solutions has been extensively studied, it remains poorly understood in solvent‐free environments. Provided here is the first example of using anionic templates to achieve selective assembly of differently‐sized macrocycles in a solvent‐free system. Using acid‐catalyzed synthesis of cyclohexanohemicucurbiturils as a model, size‐controlled, quantitative synthesis of 6‐ or 8‐membered macrocycles by spontaneous anion‐directed reorganization of mechanochemically‐made oligomers in the solid state is demonstrated.

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