Zirconium-based coordination cages have received considerable recent attention as a result of their structural tunability and amenability to postsynthetic modification. Although these structures have adopted tetrahedral (4-vertex) or cigar (2-vertex) geometries depending on the shape and nuclearity of the ligand used in their assembly, their structures have not previously been shown to be either tunable or dynamic. Here, we examine the speciation of a series of zirconium-based cages where the geometry and nuclearity of the product cage can be tuned via judicious functionalization of dicarboxylate ligands. We further show that many of these materials exist as both cage structures in solution or the solid state. With appropriate solvent exchange and activation conditions, the cigar structures can display Brunauer–Emmett–Teller (BET) surface areas as high as 123 m²/g. As a result of their expanded pore structures, the tetrahedra display significantly increased BET surface areas approaching 700 m²/g. These results show that by appropriate ligand functionalization the structures of zirconium-based cages can be modified to tune their phase and surface area. Finally, the isolation of phase-pure cages allows for the utilization of anion metathesis reactions to tune their solubility.

中文翻译：

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多孔锆配合物笼中基于配体的相位控制

基于锆的配位笼由于其结构可调性和对合成后修饰的适应性而受到了近期的关注。尽管这些结构已采用四面体（4-vertex）或雪茄（2-vertex）几何形状，具体取决于组装时所用配体的形状和核数，但以前尚未证明它们的结构是可调的或动态的。在这里，我们检查了一系列基于锆的笼子的形态，其中可以通过明智地将二羧酸酯配体官能化来调节产品笼子的几何形状和核度。我们进一步证明，这些材料中的许多都以溶液或固态两种笼状结构存在。在适当的溶剂交换和活化条件下，² /克。由于其扩大的孔结构，四面体显示的BET表面积显着增加，接近700 m ² / g。这些结果表明，通过适当的配体官能化，可以修饰锆基笼子的结构，以调节其相和表面积。最后，纯相笼的分离允许利用阴离子复分解反应来调节其溶解度。