Efficient asymmetric induction and highly stable propagating radicals in one-dimensional inclusion polymerization

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We studied the efficient asymmetric induction and highly stable propagating radicals in one-dimensional inclusion polymerization. The polymerization is dependent on a space at a molecular level, although we usually ignore the space effect at a macroscopic level. In order to clarify the effect, we compared the behavior of the former polymerization with the latter one. The results are summarized as follows :1. We carried out the inclusion polymerization of conjugated butadiene monomers by using cholic acid, deoxycholic acid and their derivatives. Deoxycholic acid and apocholic acid, served as a pair of hosts appropriate for a research of the space effect. It was found that the asymmetric induction and the stability of the propagating radicals depend on the channel size.2. We used molecular graphics for a comparison of the size and shape of the channel. We adopted the data determined from X-ray crystal structure analysis. From the analysis of lots of the cross sectional figures, we found that the size and shape of the pocket of the channel play a decisive role in the polymerization reaction.3. We succeeded in observing ESR spectra of the propagating radicals derived from conjugated butadiene monomers. It was so far very difficult due to the instability. The included radicals are difficult to recombine in the channels. Furthermore. the ESR spectra are in some cases greatly different. This is based on the molecular motion of the-radicals in the channels. We now find a close relationship among the stability of the radicals, the rate and the selectivity of the polymerization reaction.