Bottom-up construction of mesoporous supramolecular isomers based on a Pd₃L₆ triangular prism as templates for shape specific aggregation of polyiodide

Bottom-up construction of highly complex architecture from simple components remains one of the long-standing challenges in chemistry. Herein two supramolecular isomers based on large trigonal prismatic Pd₃L¹₆ building block are reported. Significantly, they can be controllably obtained by adjusting the solute concentration during crystal growth. Specifically, the square shape crystals, α-[Pd₃L¹₆](PF₆)₁₂ in the cubic system with $I\overline{4}3m$ space group, can be isolated from a high-concentration solution of Pd₃L¹₆. Interestingly, a mesoporous cage assembled from eight Pd₃L¹₆ units with a diameter of 24 Å is observed in the crystal structure. For the low-concentration solution of Pd₃L¹₆, the rectangular shape crystals β-[Pd₃L¹₆](PF₆)₁₂ are obtained, which crystallize in the hexagonal system with P6₃/m space group, and display two-dimension packing pattern and one-dimension mesoporous channels (diameter ca. 22 Å) along the c axis. Moreover, the two supramolecular isomers were used as nanoporous reactors to induce the specific formation of polyiodides with different compositions and shapes as evidenced from single crystal X-ray diffraction studies. These findings provide a reference in targeting functional crystalline mesoporous supramolecular materials from a single complex building unit.