Programmed Molecular Self-assembly Utilizing Transition Metals : Synthesis and Function of Nano-scale Molecular Materials

在本项目中，我们重点研究了利用过渡金属进行程序化分子自组装来合成纳米级分子材料及其功能。在这里，我们总结了我们的研究成果，分为五个主题。(1)内官能化分子球的自组装：我们成功地形成了一个液状的氟液滴，它由24个全氟烷基链组成，限制在一个5纳米大小的近似球形的壳层内部。这些结构是由12个钯离子和24个桥联配体在溶液中自发组装而成。(2)光可切换分子链状物：我们实现了一种精确、清洁的光操作的分子锁。由于在紫外光照射下，惰性的铂(II)-吡咯键被相当程度地固定，我们证明了通过配位环的单向连接来实现光可切换的分子锁。(3)自组装宿主对寡肽的选择性识别和折叠：我们预计，自组装宿主的大疏水空腔可以取代蛋白质支架，稳定寡肽的二级结构。(4)自组装主体内的异常化学反应：我们发现，水自组装笼子在菲和邻苯二甲酰亚胺分子的Diels-Alder反应中诱导了非常不寻常的区域选择性，促进了末端环上的反应。(5)自组装主体中不稳定过渡物种的直接结晶学观察：我们成功地在自组装的配位笼中原位观察到了配位不饱和金属络合物。

In this project, we have focused on the synthesis and function of nano-scale molecular materials by programmed molecular self-assembly utilizing transition metals. Here we summarize our research results that are divided into the five topics. (1)Self-assembly of endo-functionalized molecular spheres : we succeeded in the formation of a liquid-like fluorous droplet, composed of 24 perfluoroalkyl chains confined in the interior of a 5-nanometer-sized, roughly spherical shell. The structures were spontaneously assembled in solution from 12 palladium ions and 24 bridging ligands. (2)Photo-switchable molecular catenate : We achieved a precise, clean molecular lock that operates by light. Since the inert Pt(II)-py bond is considerably labialized upon UV irradiation, we demonstrated the photo-switchable molecular lock by the one-way catenation of coordination rings. (3)Selective recognition and folding of oligopeptides by self-assembled hosts : We anticipated that the large hydrophobic cavity of self-assembled hosts could replace the protein scaffolds and stabilize the secondary structures of oligopeptides. (4)Unusual chemical reactions within self-assembled hosts : We found that an aqueous self-assembled cage induces highly unusual regioselectivity in the Diels-Alder reactions of anthracene and phthalimide molecules, promoting reaction at a terminal ring. (5)Direct crystallographic observation of unstable transition species within self-assembled hosts : We succeeded in the in situ crystallographic observation of a coordinatively unsaturated metal complex within a self-assembled coordination cage.