Department of Chemistry and Biochemistry, University of Kitakyushu , Fukuoka 808-0132, Japan.
Langmuir. 2016 Nov 29;32(47):12434-12441. doi: 10.1021/acs.langmuir.6b01671. Epub 2016 Jul 20.
Supramolecular self-assembly and the resulting chiral transfer from the molecular level to the nanoscale is a major topic in modern supramolecular chemistry. We synthesized a galactose-bearing calix[4]arene surfactant (chiral) and mixed it with a primary amine-bearing analogue (achiral). The mixture showed strong induced circular dichroism (ICD) at an almost 3:2 molar ratio of the two surfactants, and exothermic heat was observed upon mixing. The magnitude of ΔH was comparable to that of van der Waals interactions. This phenomenon indicated that the ICD can be ascribed to the formation of a new supramolecular assembly in which the stoichiometric interaction between the two molecules leads to complexation and the resultant complex has chiral morphology. Transmission electron microscopy and small-angle X-ray scattering showed that the galactose-bearing surfactant forms vesicles, and the mixing induces a transition from the vesicles to threadlike cylinders with a diameter of ∼3.0 nm. We presume that these cylinder are twisted because of chiral transfer from the chiral galactose moiety and show ICD.
超分子自组装以及由此产生的从分子水平到纳米尺度的手性传递是现代超分子化学的一个主要课题。我们合成了一种带有半乳糖的杯[4]芳烃表面活性剂（手性），并将其与带有伯胺的类似物（非手性）混合。在两种表面活性剂的摩尔比接近 3:2 时，混合物表现出强烈的诱导圆二色性（ICD），并且在混合时观察到放热。ΔH 的大小与范德华相互作用相当。这一现象表明，ICD 可以归因于新的超分子组装的形成，其中两个分子之间的化学计量相互作用导致络合，所得络合物具有手性形态。透射电子显微镜和小角 X 射线散射表明，带有半乳糖的表面活性剂形成囊泡，混合诱导从囊泡到直径约 3.0nm 的线状圆柱的转变。我们推测这些圆柱由于来自手性半乳糖部分的手性传递而扭曲，并表现出 ICD。
