Huang Xin, Li Chao, Jiang Siguang, Wang Xuesong, Zhang Baowen, Liu Minghua
CAS Key Laboratory of Colloid and Interface Science, Institute of Chemistry, CAS, 100080, Beijing, People's Republic of China.
J Colloid Interface Sci. 2005 May 15;285(2):680-5. doi: 10.1016/j.jcis.2004.12.025.
Complex monolayers of barbituric acid and melamine were formed by spreading a chloroform solution of amphiphilic barbituric acid on the subphase of melamine solution. It was confirmed that the complex monolayer was formed through in situ complementary hydrogen bonding at the air-water interface. It was interesting to find that the complex LB films showed supramolecular chirality although both of the molecules were achiral, as verified by the circular dichroism spectral measurements. It was suggested that the pi-pi stacking of the neighboring barbituric acid and melamine group in a helical sense resulted in the chirality of the molecular assemblies. Due to the directionality of the hydrogen bonding, the BA-M film could form regular aligned nanofibers on the AFM images. Increasing the subphase temperature will lead to the decrease of CD intensity and the change of the morphologies. We suggested that the strength of the hydrogen bonding resulted in the difference.
通过将两亲性巴比妥酸的氯仿溶液铺展在三聚氰胺溶液的亚相上，形成了巴比妥酸和三聚氰胺的复合单层。证实了复合单层是通过在气-水界面原位形成互补氢键而形成的。有趣的是，尽管两个分子都是非手性的，但通过圆二色光谱测量证实，复合LB膜显示出超分子手性。有人认为，相邻的巴比妥酸和三聚氰胺基团以螺旋方式进行π-π堆积导致了分子组装体的手性。由于氢键的方向性，BA-M膜在原子力显微镜图像上可以形成规则排列的纳米纤维。提高亚相温度会导致圆二色强度降低和形态变化。我们认为氢键强度导致了这种差异。
