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

研究了一维包合聚合中高效的不对称诱导和高稳定的增长自由基。聚合反应在分子水平上依赖于空间，尽管我们通常忽略宏观水平上的空间效应。为了阐明这种影响，我们比较了前者和后者的聚合行为。主要研究结果如下：1.以胆酸、脱氧胆酸及其衍生物为原料，进行了共轭丁二烯单体的包合聚合。去氧胆酸和去氧胆酸是一对适合于空间效应研究的主体。研究发现，非对称诱导和传播自由基的稳定性依赖于通道尺寸.我们使用分子图形来比较通道的大小和形状。我们采用了X射线晶体结构分析测定的数据。通过对大量截面图的分析，我们发现通道口袋的大小和形状对聚合反应起着决定性的作用.我们成功地观察到共轭丁二烯单体产生的增长自由基的ESR谱。到目前为止，由于不稳定，这是非常困难的。所包含的自由基难以在通道中重组。此外。ESR谱在某些情况下有很大的不同。这是基于通道中自由基的分子运动。我们现在发现自由基的稳定性、聚合反应的速率和选择性之间有密切的关系。

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.