In terms of both intrinsic binding from the thermodynamic perspective and constrictive binding from the kinetic perspective , the irreversible complexes include noncovalent irreversible complexes that are self-assembled by two molecules between which there is no covalent bond. Here, the intrinsic binding is the complexation governed by intermolecular interactions between the two molecules as well as between the solvent and each of the two molecules, while the constrictive binding is the complexation controlled by the thermal energy required for the guest to overcome the steric hindrance from the host during the assembly or disassembly process as exemplified below by Cram's supramolecular capsules known as carcerand , hemicarcerand , and neocarcerand .