Polycatenanes Linked by Topological Bonds

In this section the unprecedented oligocatenanes, i.e. the [5]- and [7]catenanes 30 and 31 and the scarce experimental approaches to high molecular-weight linear polycatenane 9 have been presented. No synthetic Olympic network 32 has been reported to date, although their DNA analogs are known. The next section is dedicated to a new type of macromolecular architecture, structurally related to polycatenane 9, i.e. poly[2]catenanes. 

3 Poly[2]catenanes Linked by Alternating Topological and Covalent Bonds 

The rings bearing the substituents OUT (IN) of the catenane structure are referred to as OUT (IN) rings, respectively [3, 41, 57b]. 

It has been observed that the isomers 41c,d and 42c,d have the same low reactivity towards polycondensation, irrespective of the reaction conditions and that only oligo[2]catenanes were reached [30, 56], This important finding rules out the 

The high rigidity of the catenane segments has been demonstrated by a temperature-dependent NMR spectroscopic study of the catenane monomers 44 and 46 [37, 52], Almost no temperature dependence was observed for the line shape of the spectra of the catenane monomers 44 and 46 whereas the temperature had a dramatic influence on the spectra of the unmethylated catenanes 41b,d and 42b,d [30, 37, 52, 56]. Therefore, the poly[2]catenanes 48 and 49 represent one extreme case where there is very little relative mobility of the macrocycles of the catenane segments. 

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