Guest‐Induced, Self‐Assembled Supramolecular Capsule: Effect of Guest and Counter Anions

Abstract

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.

Self-assembled Cages and Capsules Using Cyclotriveratrylene-type Scaffolds

“…The hydroxy groups of CTC are potential hydrogen-bonding groups, and dimeric CTC capsules form in solution and solid state through a self-assembly templated by binding NEt 4 + cations within the capsule. 16 Earlier reports showed that dimeric hydrogen-bonded capsules of partially deprotonated CTC can be isolated in the solid state with encapsulated NEt 4 + guests. These capsules were not entirely closed and had a clam-shell like appearance (Figure 1).…”