超分子凝胶体系的动态手性传递、手性识别和催化研究

Chirality is a basic character of nature, where much chiral structures related to life are found, such as α-helical polypeptide in protein, double-helical DNA and triple helical collagen fiber. Supramolecular chirality defines the chirality at the supramolecular level, which is generated from assemblies based non-covalent interactions such as hydrogen bonding, van der Waals interactions, metal-ligand coordination and so on. It is related not only to the chirality of the molecules, but also largely related to the assembly manner of the molecules. The transmission of chirality from the molecular level to the macro- or supramolecular level is a hot issue, because it not only mimics the natural biological structures, but has potential application in the field of enantioselective recognition, asymmetric catalysis and liquid crystal materials. The process of chirality transfer can be realized either in a synthetic process or by virtue of supramolecular chemistry approach. In the supramolecular way, the chirality transfer can be realized from a chiral matrix or template to achiral molecules through various noncovalent interactions such as π-π stacking, hydrogen bonding, electrostatic and hydrophobic interactions. These noncovalent interactions should be appropriate to preserve the initial chiral matrix and to induce the chiral information transfer. Among various self-assembled systems, supramolecular gels generated by low molecular weight molecules through non-covalent interactions provided a matrix for chirality transfer. Herein, in order to study the molecular scale chiral "information" being programmed into supermolecules, mixture systems of chiral gelators with achiral dopants are designed. The co-assembly assemblies through non-covalent interaction will lead to the transfer of chirality. Thus, various molecules, even macromolecules can be introduced into a chiral supramolecular gel, providing a large library to investigate the supramolecular chirality. Further, chirality at the supramolecular level being transferred to the molecular level will be also described. In this way, asymmetric catalysis and enantioselective recognition by chiral supermolecules can be regarded as effective ways to transfer supramolecular chirality to molecular level. The formed chiral nanostructures may provide a high density of recognition or catalytic sites and chiral microenvironment suitable for recognition and asymmetric reaction, thus, the chiral nanostructures will be benefit for the enantiomeric selectivity. Both the transfer of molecular chirality to the supramolecular level and chirality transfer from the supramolecular to the molecular level will be investigated in this project.

手性是自然界最重要的属性之一，与生命的起源，运营密切相关。由非共价相互作用而形成的手性空间结构或分子不对称排列所表现出来的超分子手性架起了分子手性和宏观手性的桥梁。对超分子手性的研究，有助于理解手性在生物体结构与功能中发挥的关键作用，也有助于开发新的手性功能材料。手性的传递与逐级放大行为是超分子手性研究的重要内容，而超分子凝胶是实现手性逐级传递的重要体系。我们拟通过一系列两亲分子胶凝剂，将其与功能小分子及高分子共组装形成二组分或多组分凝胶，实现分子手性到各种功能基团的传递，并通过pH、光等外场刺激研究手性的动态传递。同时，超分子手性有望实现不同于分子手性的新功能， 我们将进一步以形成的超分子手性组装体为基础，开展手性识别、手性催化等方面的工作，揭示手性超分子的特殊性能。

手性是自然界的普遍特征，从生物分子的结构，到各种生化反应和生理活动，都体现出强烈的手性效应。有关由非共价相互作用而形成的手性空间结构或分子不对称排列所表现出来的超分子手性的研究搭建了分子手性和宏观手性的桥梁，为理解手性在生物体结构与功能中发挥的关键作用提供理论基础。本项目围绕着自组装结构中的手性产生，放大，传递等重要基础科学问题开展研究工作，加深了对超分子手性产生的认识，从丰富组装结构，理解组装驱动力的协同等方面着手利用分子间各种非共价相互作用组装形成手性超分子结构，研究了溶剂，温度，金属离子，酸碱和光辐照等对超分子手性和手性纳米结构的调控，初步理解了分子手性与超分子手性及形成的纳米结构的手性之间的关联，并对各种手性结构进行有效的调控，凸显了手性超分子的智能响应特性，为后续手性超分子的功能体现提供基础。进一步探索了自组装结构在手性识别和不对称催化等领域的应用，总体上表现出组装基元分子手性的协同和放大功效。.项目实施过程中共发表论文SCI论文18篇，其中Angew. Chem. Int. Ed. 1篇, Adv. Mater. 2篇, Acs Nano 1篇。课题负责人多次在胶体界面，超分子，手性、以及相关学科的国内外会议上做报告。