Constructing Metallo-Supramolecular Cuboctahedra Incorporating Flexible Alkyl-Diamines via Postassembly Ligand Exchange

Coordination-driven self-assembly offers a powerful toolkit for constructing sophisticated functional architectures. Rigid ligands are widely employed as building blocks in metallo-supramolecular chemistry due to their structural predictability during self-assembly. In contrast, flexible building blocks─though capable of offering greater structural diversity and stimuli-responsiveness─are rarely used, as their conformational freedom often complicates structural control. Consequently, the integration of flexible ligands into metallo-supramolecular systems remains underexplored. To address this challenge, we employ a postassembly ligand-exchange approach to construct a series of heteroleptic metallo-supramolecular cuboctahedra incorporating both rigid and flexible ligands. Investigations of chain length dependence reveal that flexible alkyl-diamine incorporation affects cage hydrodynamic size and stability, with optimal stability achieved at 8 units. This combined bottom-up and top-down synthetic approach offers a promising strategy for engineering complex architectures from flexible building blocks for further exploration of chemistry within a confined space.