Department of Organic and Polymer Chemistry, College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083, China.
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin 130012, China.
Nat Commun. 2017 May 19;8:15476. doi: 10.1038/ncomms15476.
Five- and six-pointed star structures occur frequently in nature as flowers, snow-flakes, leaves and so on. These star-shaped patterns are also frequently used in both functional and artistic man-made architectures. Here following a stepwise synthesis and self-assembly approach, pentagonal and hexagonal metallosupramolecules possessing star-shaped motifs were prepared based on the careful design of metallo-organic ligands (MOLs). In the MOL design and preparation, robust ruthenium-terpyridyl complexes were employed to construct brominated metallo-organic intermediates, followed by a Suzuki coupling reaction to achieve the required ensemble. Ligand LA (VRuX, V=bisterpyridine, X=tetraterpyridine, Ru=Ruthenium) was initially used for the self-assembly of an anticipated hexagram upon reaction with Cd or Fe; however, unexpected pentagonal structures were formed, that is, [CdLA] and [FeLA]. In our redesign, LB [V(RuX)] was synthesized and treated with 60° V-shaped bisterpyridine (V) and Cd to create hexagonal hexagram [CdVLB] along with traces of the triangle [CdV]. Finally, a pure supramolecular hexagram [FeVLB] was successfully isolated in a high yield using Fe with a higher assembly temperature.
五角星和六角星结构在自然界中以花朵、雪花、树叶等形式频繁出现。这些星形图案也经常被应用于功能性和艺术性的人造建筑中。在这里，我们采用逐步合成和自组装的方法，基于对金属有机配体（MOL）的精心设计，制备了具有星形结构的五边形和六边形金属超分子。在 MOL 的设计和制备中，我们采用了坚固的钌-三联吡啶配合物来构建溴化的金属有机中间体，然后通过 Suzuki 偶联反应实现所需的配合物。配体 LA（VRuX，V=双吡啶，X=四吡嗪，Ru=钌）最初用于与 Cd 或 Fe 反应，预期形成六边星形图案，但却形成了意想不到的五角星形结构，即[CdLA]和[FeLA]。在我们的重新设计中，合成了 LB[V(RuX)]，并与 60°V 形双吡啶（V）和 Cd 反应，生成了六角星形的六边星形图案[CdVLB]，同时还生成了少量三角形图案[CdV]。最后，使用 Fe 和更高的组装温度，成功地以高产率分离出纯的超分子六边形图案[FeVLB]。
