Rotaxanes topological chemistry

Amide-linked catenanes and rotaxanes, readily accessible via nonionic template synthesis, are molecules with fascinating topology, but their final breakthrough was only achieved when they became substrates for further chemical derivatiza-tion. A potential reaction site in the catenanes and rotaxanes presented so far is the sulfonamide group, because the proton can be selectively abstracted in the presence of carbon amide groups. Subsequent alkylation offers numerous possibilities of catenane and rotaxane chemistry. 

Metallodendrimers are an interesting class of molecules in the area of dendrimer chemistry. They combine dendritic structures with the specific activity of metal complex centers. Metal coordination has facilitated the synthesis of a number of dendritic, supramolecular structures. Metals have been incorporated in all of the topologically different parts of dendrimers in the repeat or branching unit, in the molecular core and in the peripheral units. Because this field of metallodendrimers has been reviewed recently [195-197], only a few examples are given below. Other supramolecular organizations such as catenanes and rotaxanes have been mentioned previously in this chapter. 

As suggested in our discussion of supramolecular chemistry in Section 4.3, the facile preparation of complex catenanes and rotaxanes using the various preorganization strategies has led to the consideration of a number of novel stereochemical situations. Topolog-... 

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