The complex formation of alpha,omega-dicarboxylic acids and alpha,omega-diols with cucurbituril and alpha-cyclodextrin. The first step to the formation of rotaxanes and polyrotaxenes of the polyester type

The formation of mechanically bound molecules in relative high yields is on ly possible if preorganized molecules are used. Thus, the complex formation between alpha,omega-dicarboxylic acids and alpha,omega-diols and the macro cyclic ligands cucurbituril and alpha-cyclodextrin was examined using calor imetric titrations. Both ligands are able to form relative strong complexes with the molecules examined. However, for the formation of rotaxane-polyes ters it is essential that the reactive groups of the complexed molecules ar e located outside of the cavities of the preorganized complexes.