Stereochemical configuration of polyfumarates as studied by 13C nuclear magnetic resonance spectroscopy
Stereochemical configuration of polyfumarates as studied by 13C nuclear magnetic resonance spectroscopy
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13C核磁共振波谱研究聚富马酸酯的立体化学构型
DOI：
10.1002/macp.1988.021890809
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发表时间：
1988
影响因子：
2.5
通讯作者：
T. Otsu
中科院分区：
文献类型：
--
作者：
Xiaogong Wang;T. Kōmoto;I. Ando;T. Otsu
通过自由基聚合制备的一些聚（富马酸二烷基酯）（PDAF）和聚（富马酸二环烷基酯）（PDCF）的 125 MHz 13C NMR 谱是在 60°C 的 CDCl3 溶液中测量的。使用模型化合物和计算机模拟，将主链碳原子和酯羰基碳原子的多重共振分别分配给立体化学三元组和五元组序列。从这些结果发现，PDAF和PDCF基本上表现出无规立构结构，内消旋加成优于外消旋加成，并且内消旋与外消旋含量的比例随着不同种类的烷基和环烷基而变化。聚合物的立构序列比例不能用单参数伯努利统计来解释，但可以用改进的伯努利试验成功地解释。
The 125 MHz 13C NMR spectra of some poly(dialkyl fumarates) (PDAF) and poly(dicycloalkyl fumarates) (PDCF) prepared by radical polymerization are measured in CDCl3 solution at 60°C. The multiplet resonances of the main-chain carbon atoms and the ester carbonyl carbon atoms are assigned to stereochemical triad and pentad sequences, respectively, using model compounds as well as computer simulation. From these results it is found that PDAF and PDCF exhibit essentially atactic structures with meso addition favoured over racemic addition, and that the ratio of meso to racemic content varies with different kinds of alkyl and cycloalkyl groups. The tactic sequence proportions of the polymers cannot be explained by one-parameter Bernoullian statistics, but can be successfully explained by modified Bernoullian trial.