Tetraamido-oxacalix[4]arene Derivatives： Synthesis, Structures and Supramolecular Assemblies

Tetraamido-oxacalix[4]arene derivatives have been synthesized via the reactions of tetraamino-oxacalix[4]arene with excess butyryl chloride, octanoyl chloride, benzoyl chloride and p-toluenesulfonyl chloride, respectively. JH NMR results suggest that these oxacalix[4]arene derivatives preferentially adopt the 1,3-alternate （saddle-like） con- formation in solution, which were also the case in the solid state as demonstrated by single crystal X-ray analysis. A dimerized slipped capsule could be formed by tetra-butyramido-oxacalix[4]arene in the solid state via intermolecu- lar hydrogen bond interactions under the assistance of two encapsulated methanol molecules. On the other hand, a molecular cavity was formed by tetra-p-toluenesulfonamido-oxacalix[4]arene which can encapsulate a solvent molecule of ethyl acetate.