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

在本项目中，我们主要研究利用过渡金属进行程序化分子自组装的纳米级分子材料的合成和功能。在这里，我们总结了我们的研究成果，分为五个主题。(1)内功能化分子球的自组装：我们成功地形成了一个液体状的含氟液滴，由24个全氟烷基链组成，被限制在一个5纳米大小的近似球形的壳内。这些结构由12个钯离子和24个桥接配体在溶液中自发组装而成。(2)光开关分子链：我们实现了一种精确、清洁的分子锁，它可以通过光来操作。由于惰性Pt(II)-py键在紫外线照射下被明显地标记化，我们通过配位环的单向螯合证明了光开关分子锁。(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)自组装宿主体内的异常化学反应：我们发现，水溶液自组装笼在蒽和邻苯二甲酸亚胺分子的Diels-Alder反应中诱导了高度异常的区域选择性，促进了末端环上的反应。(5)自组装宿主体内不稳定过渡态的直接晶体学观察：我们成功地在自组装的配位笼内对一个配位不饱和金属配合物进行了原位晶体学观察。

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.