Polymer Formation by Intermolecular Interactions

Kaifer et al. [29] reported electrochemically controlled intermolecular dimeric com-plexation of viologen-modified fi-CDs in aqueous solutions (Fig. 3.7). Harada et al. [30] have found that the H NMR signal of the phenyl part of the 6-hydroxycinnna-moyl a-CD (6-HyCiO-a-CD) gave slight peak-shifts as the concentration increased. They found that 6-HyCiO-a-CD formed a weak intermolecular complex in aqueous solutions (Fig. 3.6 (b)). Kaneda et al. [32, 33] previously reported the formation of a cyclic dimer formed by azobenzene-derivative-substituted permethylated a-CDs in equilibrium (Fig. 3.8). Liu et al. [34, 35] reported on the dimerization 

6-HyCiO-j8-CD was found to form intramolecular complexes and 6-HyCiO-a-CD was found to form weak intermolecular complexes. These results indicate that a hydrocinnamoyl group is too flexible to form intermolecular complexes. As a result, Harada et al. have attempted to use a more rigid spacer such as a cinnamoyl derivative with a double bond. 

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