Wang Yan, Yang Shu-Gui, Li Ya-Xin, Cao Yu, Liu Feng, Zeng Xiang-Bing, Cseh Liliana, Ungar Goran
State Key Laboratory for Mechanical Behaviour of Materials, Shaanxi International Research Center for Soft Matter, Xi'an Jiaotong University, 710049, Xi'an, China.
School of Chemistry and Chemical Engineering, Henan University of Technology, 450001, Zhengzhou, China.
Angew Chem Int Ed Engl. 2024 Jun 3;63(23):e202403156. doi: 10.1002/anie.202403156. Epub 2024 May 2.
Among the intriguing bicontinuous self-assembled structures, the gyroid cubic is the most ubiquitous. It is found in block and star polymers, surfactants with or without solvent, in thermotropic liquid crystals with end- or side-chains, and in biosystems providing structural color and modelling cell mitosis. It contains two interpenetrating networks of opposite chirality and is thus achiral if, as usual, the content of the two nets is the same. However, we now find that this is not the case for strongly chiral compounds. While achiral molecules follow the opposite twists of nets 1 and 2, molecules with a chiral center in their rod-like core fail to follow the 70° twist between junctions in net 2 and instead wind against it by -110° to still match the junction orientation. The metastable chiral gyroid is a high-entropy high-heat-capacity mesophase. The homochirality of its nets makes the CD signal of the thienofluorenone compounds close to that in the stable I23 phase with 3 isochiral nets.
在引人入胜的双连续自组装结构中，螺旋立方结构最为常见。它存在于嵌段和星形聚合物、有无溶剂的表面活性剂、具有端链或侧链的热致液晶以及提供结构颜色和模拟细胞有丝分裂的生物系统中。它包含两个具有相反手性的相互贯穿网络，因此，如果像通常情况那样两个网络的含量相同，则它是非手性的。然而，我们现在发现对于强手性化合物并非如此。非手性分子遵循网络1和网络2的相反扭曲，而在其棒状核心中具有手性中心的分子未能遵循网络2中节点之间70°的扭曲，而是以-110°的角度逆向扭曲，以仍然匹配节点方向。亚稳手性螺旋立方是一种高熵高热容中间相。其网络的同手性使得噻吩并芴酮化合物的圆二色信号与具有3个等手性网络的稳定I23相中的信号相近。
