Guest-Controlled Formation of a Hydrogen-Bonded Molecular Capsule

The dimerization of the self-complementary resorcarene tetraesters is triggered by the entrapment of a tropylium cation in the pi-basic cavity. Eight intermolecular OH small middle dot small middle dot small middle dotOC hydrogen bonds together with host-guest interactions such as charge transfer and C-H small middle dot small middle dot small middle dotpi bonding are responsible for the high stability of this assembly (see picture). Hereby neither the host-guest interaction nor the interaction of two resorcarene molecules through hydrogen bonds is sufficient by itself to form the complex.