Brizard Aurélie, Oda Reiko, Huc Ivan
Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, 33607, Pessac, France.
Top Curr Chem. 2005;256:167-218. doi: 10.1007/b107174.
Chirality seems to be intimately associated with the growth and stability of self-assembled fibrillar networks and with the most common macroscopic property of these networks, which is the thermoreversible gelation of the solvent. The presence and the relative configurations of stereogenic centers in the structure of a small molecule gelator are generally (but not always) observed to be critical to its ability to form gels. Symmetry considerations of chiral molecular packing provide thermodynamic and kinetic arguments that may explain why chirality favors fiber growth. Additionally, molecular chirality is sometimes expressed at a scale of nanometers or micrometers and gives rise to twisted or coiled fiber structures that are readily observable by microscopic techniques. These chiral fiber morphologies have already found some applications as templates for helical protein crystallization or for the growth of chiral inorganic replicas. The chiroptical properties of assembled chiral molecules, e.g., circular dichroism, allow monitoring of aggregation and may sometimes give insights into molecular packing. But determining chiral molecular arrangements in the fibers remains a challenge and requires the use of multiple techniques.
手性似乎与自组装纤维状网络的生长和稳定性以及这些网络最常见的宏观性质密切相关，这种宏观性质就是溶剂的热可逆凝胶化。小分子凝胶剂结构中手性中心的存在及其相对构型通常（但并非总是）被观察到对其形成凝胶的能力至关重要。手性分子堆积的对称性考量提供了热力学和动力学论据，这或许可以解释为什么手性有利于纤维生长。此外，分子手性有时会在纳米或微米尺度上表现出来，并产生通过显微镜技术很容易观察到的扭曲或盘绕的纤维结构。这些手性纤维形态已经在作为螺旋蛋白结晶的模板或手性无机复制品的生长方面得到了一些应用。组装的手性分子的手性光学性质，例如圆二色性，能够监测聚集情况，并且有时可能有助于深入了解分子堆积。但是确定纤维中手性分子的排列仍然是一项挑战，需要使用多种技术。
