The self-organization behavior of an amphiphilic sexithiophene bearing amide functionalities is studied and compared to that of a derivative bearing an ester group at the same position. The introduction of hydrogen-bond interactions in assemblies of these π-conjugated oligomers is found to affect the molecular organization both in protic media and in thin deposits on mica. The amphiphilic 2,2′;5′,2'';5'',2''';5''',2'''';5'''',2'''''-sexithiophene-5,5'''''-dicarboxylic acid bis[(4,7,10,13,16-pentaoxaheptadecyl)amide] forms assemblies in n-butanol and water and partially aggregates in toluene. Spectroscopy reveals that the presence of a hydrogen-bonding moiety increases the thermal stability of the assemblies in n-butanol and even more in water solution. On mica surfaces, the formation of rod-like one-dimensional nanostructures is observed after deposition from toluene solutions. In addition, transmission electron microscopy in combination with selected area electron diffraction shows that in water plate-like structures are formed built from parallel oriented stacks, with a π–π distance of 3.5 Å. Comparison of these data to molecular modeling and quantum chemistry calculations is used to better understand the influence of the amide group on the stacking of these compounds. The introduction of these H-bonding interactions leads to denser and more stable stacks. Furthermore, we show that a derivative of the amide compound, bearing terminal ammonium groups, forms a complex with chiral polyanions in aqueous media such that the sexithiophene segments are stacked in a meta-stable helical fashion with preferred handedness. We observed that poly(glutamate) and DNA generate a chiral sexithiophene assembly. In time the induced chirality disappears, which is explained by the meta-stability of the kinetically formed adduct. This constitutes one step forward towards the controlled formation of functional multi-component systems in aqueous solution.
将中文直接呈现给您:具有酰胺功能性的两亲性六
噻吩的自组装行为被研究并与在相同位置具有酯基的衍
生物进行了比较。在这些π-共轭低聚物的组装中引入氢键相互作用,发现在质子性介质和在
云母上的薄沉积物中影响分子组织。两亲性2,2′;5′,2'';5'',2''';5''',2'''';5'''',2'''''-六
噻吩-5,5'''''-二
羧酸双[(4,7,10,13,16-五氧
十七烷)酰胺]在
正丁醇和
水以及在
甲苯中部分聚集。光谱表明,氢键基团的存在增加了组装在
正丁醇中的热稳定性,在
水溶液中更是如此。在
云母表面,从
甲苯溶液沉积后观察到棒状的一维纳米结构形成。此外,透射电子显微镜结合选区电子衍射显示,在
水溶液中形成了由平行定向的堆叠构成的板状结构,π–π距离为3.5 Å。将这些数据与分子建模和量子
化学计算进行比较,以更好地理解酰胺基团对这些化合物堆叠的影响。这些氢键相互作用的引入导致更密集和更稳定的堆叠。此外,我们表明,具有末端
铵基团的酰胺化合物衍
生物在
水性介质中与手性多阴离子形成复合物,使得六
噻吩片段以亚稳态螺旋方式堆叠并具有优先手性。我们观察到聚谷
氨酸和DNA生成了手性的六
噻吩组装。随着时间的推移,诱导的手性消失,这是由于动力学形成的加合物的亚稳态特性解释的。这构成了在
水溶液中有控制地形成功能性多组分系统的一步进展。