Guest molecules, topological encapsulation

The cage compound 3 also exhibited a remarkable ability to encapsulate C-shaped molecules such as ds-azobenzene (5) and -stilbene (6) derivatives [19]. These guest molecules enclathrated in the cavity via the formation of a hydrophobically interacted dimer with a topology reminiscent of a hydrogen-bonded tennis ball [20] (Fig. 5a). This hydrophobic dimer is supported by an... 

Figure 7.2 Encapsulation of small guest molecules and dispersion of nanoparticles by amphiphilic molecules with linear structure (top) and highly branched pol aners with micelle-like topology (bottom).

The topology of molecules can drastically influence their supramolecular chemistries and properties in general. For example, dendrimers or hyperbranched polymers show dramatically different properties when compared with their linear counterparts. To take a recent example, hyperbranched polyglycerols with a core-shell amphiphile structure encapsulate guests and thereby act as phase-transfer agents, while their strictly linear countei-parts do not.f i... 

The guest moiety is spherical and encapsulated in a cavity-like structure formed by the cyclic or open-chain host molecule. The cavity either exists as such in the ligand or the latter adopts its final shape upon complexation, a process associated with structural and conformational rearrangements. In any case, a mutual topological fit between the two reacting entities is essential for the stabilization of the complex. A good ionophore must therefore meet the following requirements ... 

From a strictly topological standpoint, this family of polyoxovanadates (Figure 4.21) illustrates a very peculiar process of molecular organization in inorganic chemistry. Encapsulation of anions of molecules within shells themselves anionic in nature appears to influence and control the architecture of the system, and hence the use of the terms Template or guest-host supercomplexes, which are reminiscent of the chemistry of zeolites or of supramolecular organic chemistry (75). 

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