School of Chemical Engineering and Technology , Xi'an Jiaotong University , Xi'an , Shaanxi 710049 , China.
Department of Chemistry , The University of Texas at Austin , Austin , Texas 78712-1224 , United States.
J Am Chem Soc. 2019 Mar 20;141(11):4749-4755. doi: 10.1021/jacs.9b01042. Epub 2019 Mar 11.
Different pyridine dipyrrolate cages including cage-based dimers and polymers may be fabricated in a controlled manner from the same two starting materials, namely, an angular ligand 1 and Zn(acac), by changing the counter cation source. With tetrabutylammonium (TBA) and dimethyl viologen (DMV), Cage-3 and Cage-5 are produced. In these cages, two ligands act as bridges and serve to connect together two cage subunits to produce higher order ensembles. In Cage-3 and Cage-5, the TBA and DMV counter cations lie outside the cavities of the respective cages. This stands in contrast to what is seen with a previously reported system, Cage-1, wherein dimethylammonium (DMA) counter cations reside within the cage cavity. When the counter cations are tetraethylammonium (TEA) and bis(cyclopentadienyl) cobalt(III) (CpCo), polymeric cage materials, PC-1 and PC-2, are formed, respectively. The counter cations thus serve not only to balance charge but also to tune the structural features as a whole. The organic cations used in the present study also act to modulate the further assembly of individual cages. The present cation-based tuning emerges as a new method for a fine-tuning of the multidimensional morphology of self-assembled inorganic materials.
不同的吡啶二吡咯烷酮笼状化合物，包括基于笼状的二聚体和聚合物，可以通过改变抗衡阳离子源，从相同的两种起始原料，即角状配体 1 和 Zn(acac)，以可控的方式制备。使用四丁基铵（TBA）和二甲氧基乙烯基（DMV），可以制备笼状化合物 3 和笼状化合物 5。在这些笼状化合物中，两个配体作为桥接物，用于连接两个笼状亚基，以产生更高阶的集合体。在笼状化合物 3 和笼状化合物 5 中，TBA 和 DMV 抗衡阳离子位于各自笼状化合物的腔体外。这与之前报道的笼状化合物 1 形成鲜明对比，在笼状化合物 1 中，二甲基铵（DMA）抗衡阳离子位于笼状化合物腔内。当抗衡阳离子为四乙基铵（TEA）和双（环戊二烯基）钴（III）（CpCo）时，分别形成聚合笼状材料 PC-1 和 PC-2。抗衡阳离子不仅平衡电荷，而且整体调节结构特征。本研究中使用的有机阳离子还可以调节单个笼状化合物的进一步组装。目前基于阳离子的调谐方法是精细调整自组装无机材料多维形态的新方法。
