Controlling the Arrangement of [Fe₄L₆]⁸⁺ Cages in the Solid State

Metallosupramolecular cages are widely studied for their unique host-guest properties in solution yet translating these functionalities to the solid state remains challenging due to cavity inaccessibility and dense packing. Here, we demonstrate a hierarchical approach that employs halogen bonding to control the spatial arrangement of tetrahedral [Fe₄L₆]⁸⁺ cages in the solid state. By incorporating perfluorinated halogen bond donors of varying geometry, we demonstrate selective modulation of cage packing motifs without disrupting the cage architecture. Structural analysis reveals that incorporation of 1,3,5-triiodotrifluorobenzene disrupts the robust honeycomb arrangement, producing a distorted cubic lattice with significantly reduced cage density and potentially enhanced cavity accessibility. This approach offers a pathway to design tunable porous molecular solids, ultimately enabling the transfer of solution-phase properties to the solid state for applications in catalysis, separations, and molecular recognition.