Bowl shaped molecules are useful for making molecular capsules with suitable non-covalent bonds. We appended cyclotriguaiacylene with biologically important adenine and thymine to make capsule in solution by hydrogen bonding.

Molecular containers or supramolecular capsules are a subject of great interest because of their potential utilizations in various fields of chemistry, medicine, and nanoscience. They have been utilized as nanovessels for reactions and targeted drug delivery in recent years. Cyclotricatechylene (CTC) is a bowl-shaped molecule in its crown structure. It has six phenolic groups as potential hydrogen bond donors. In this work, we utilize this hydrogen bonding capability of CTC to generate supramolecular complexes with hydrogen bond acceptors such as 4,4′-bipyridine, pyrazine, 2,2′-bipyridine, and phenanthroline. These supramolecular entities were studied in the solid state by X-ray crystallography and scanning electron microscopy. They are not soluble in low polar solvents. Therefore, the hydrogen bonding behavior in solution could not be studied by NMR. Except in the case of pyrazine, capsular supramolecular assemblies were formed in all the cases. One of these capsules was studied for guest entrapment. Planar molecules such as naphthalene and pyrene were trapped inside its cavity with a little reorganization of the capsular assembly.

Molecular capsules form due to various interactions between molecules. Cyclotricatechylene (CTC) is a poly‐phenolic macrocycle that has been shown to form capsule under highly basic conditions. Here, we describe the formation of a molecular capsule under ambient conditions, from CTC by addition of a guest molecule. The capsule is most probably forming through pure electrostatic interaction between the guest and CTC. The capsule formation has been studied using solution techniques such as NMR and Mass spectroscopy. The information about capsule formation is also obtained from the solid state structure using single crystal X‐ray diffraction studies, which corroborates well with the findings in solution state. Upon changing the cation to a larger one, both capsule formation and the encapsulation are hindered. However, change of anions keeping the cation unchanged does not affect the assembly process.

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