Ralf Jäger

Catenanes and Rotaxanes of the Amide Type

Abstract New catenane (cf 3) and rotaxane (cf 26) types have been obtained in remarkable yields via supramolecular template syntheses. The amide-based mechanically bonded structures can be designed by appropriate choice of building units. The selective formation of stable outlout, idin and idout [2]catenane isomers (cf Scheme 2), which were separated, allowed conclusions concerning their mechanism of formation. It was demonstrated that one of the two macromonocycles of the catenane molecule forms initially and acts as a host cavity for a building block of the second, interlocking macrocycle. This knowledge made a simple synthesis of amide-linked rotaxanes possible. The first X-ray structural analysis of a hano-catenane revealed a self-assembled, interlocked system held together by networks of interand intramolecular hydrogen bonds, including the amide groups and the h a n oxygen atoms. There is no doubt that these new intertwined amide systems will be extendable to higher catenanes and rotaxanes.

Amide-Based Catenanes and Rotaxanes by Non-Ionic Template Synthesis

Unlike other organic molecules catenanes and rotaxanes are not only defined and held together by common chemical bonds, they also bear mechanical bonds in their structure. Catenanes (lat. catena = chain) consist of two or more macrocycles that are intertwined as the links of a chain [1]. The term rotaxane is a combination of the two Latin words rota(= wheel) and axis(= axle). Indeed, these compounds possess (at least) one wheel and one axle running through it. The latter is equipped with large stopper units that prevent the wheel from slipping off [1] (fig. 1).