Structural Regulation of Rotaxane-Polyoxometalate Ionic Crystals: Dual Channels Modulated by Cluster Size and Charge

The rich functionality of porous supramolecular assemblies is critically dependent on their topological diversity. However, constructing ionic frameworks with predictable topologies remains challenging due to the nondirectional nature of ionic interactions. This work presents a coassembly strategy using bola-cationic rotaxanes as cationic linkers and nanosized giant polyoxometalate clusters as anionic building blocks. Both size and charge of these polyanions are demonstrated to crucially govern the network topology. By modulating the structure parameters of these giant ions, the resulting ionic assemblies have been tuned from nonporous to one featuring well-defined dual channels. This approach achieves precise control over rotaxane spatial arrangement and pore architecture, advancing the design strategies for functional ionic porous materials.