Treatment of 4-(alkylamino)benzoic acid dimer phenyl esters with a base, under conditions where monomeric 4-(alkylamino)benzoic acid phenyl esters polymerize to give well-defined aromatic polyamides, affords not polymers, but cyclic trimers in good yield.
picture for the secondary structure of these polyamides in solution that the N-alkylated poly(p-benzamide)s possess a right-handed helicalconformation ((P)-helix). In the solid states, the results of X-ray crystallographic analysis of 4-(methylamino)benzoic acid oligomers substantiated that they have a helicalconformation with three monomer units per turn.
通过链增长缩聚方法合成在氮原子上带有手性侧链的聚(对苯甲酰胺)1。聚酰胺表现出明确的分子量和窄的多分散性。聚酰胺在几种有机溶剂 (CH(3)CN、CHCl(3) 和 CH(3)OH) 中的溶液显示出耦合振荡器的分散型 CD 信号特征,并且与相应的单体相比要大得多。就检测而言,CD 信号取决于聚酰胺的温度和分子量,但与溶剂无关。吸收和 CD 光谱的激子模型分析为这些聚酰胺在溶液中的二级结构提供了清晰的图片,即 N-烷基化聚(对苯甲酰胺)具有右手螺旋构象((P)-螺旋)。在固态下,