Helical folding of an arylamide polymer in water and organic solvents of varying polarity
Helical folding of an arylamide polymer in water and organic solvents of varying polarity
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DOI：
10.1039/c5py00096c
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发表时间：
2015-03
影响因子：
4.6
通讯作者：
Peng Zhang;Liang Zhang;Hui Wang;Dan‐Wei Zhang;Zhanting Li
中科院分区：
文献类型：
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作者：
Peng Zhang;Liang Zhang;Hui Wang;Dan‐Wei Zhang;Zhanting Li
以1，8-萘二甲酰亚胺-3，6-二胺为原料，通过缩合反应合成了一种两亲性芳香酰胺聚合物。聚合物和单、三、五和七聚体对照化合物的荧光和紫外-可见实验表明，聚合物可以在水和高极性和低极性的有机溶剂（包括N，N-二甲基甲酰胺、甲醇、氯仿和二氯甲烷）中形成螺旋中空折叠体。在二元溶剂中的荧光实验表明，在低极性的氯仿或二氯甲烷中，跨层分子内氢键是形成螺旋构象的主要驱动力。在高极性水和有机溶剂如甲醇中，疏溶剂性是主要驱动力。相应的N-甲基化聚合物的荧光实验表明，N-甲基化大大降低了聚合物的折叠倾向，但在极性溶剂如甲醇中，聚合物仍然可以形成螺旋构象。
An amphiphilic aromatic amide polymer has been prepared from the condensation of 1,8-naphthalimide-3,6-diamine and isophthalic acid precursors, both of which bear tetraethylene glycol chains. Fluorescence and UV-vis experiments for the polymer and mono-, tri-, penta-, and heptameric control compounds indicate that the polymer can form a helical hollow foldamer in both water and organic solvents of high and low polarity, including N,N-dimethylformamide, methanol, chloroform and dichloromethane. Fluorescence experiments in binary solvents reveal that in benign chloroform or dichloromethane of low polarity, across-layer intramolecular hydrogen bonding is the main driving force for the formation of the helical conformation. In highly polar water and organic solvents like methanol, the solvophobicity is the main driving force. Fluorescence experiments for the corresponding N-methylated polymer indicate that N-methylation reduces the folding propensity of the polymer considerably, but in polar solvents such as methanol, the polymer can still form the helical conformation.