A Filled-Honeycomb-Structured Crystal Formed by Self-Assembly of a Janus Polyoxometalate-Silsesquioxane (POM-POSS) Co-Cluster

Clusters with diverse structures and functions have been used to create novel cluster-assembled materials (CAMs). Understanding their self-assembly process is a prerequisite to optimize their structure and function. Herein, two kinds of unlike organo-functionalized inorganic clusters are covalently linked by a short organic tether to form a dumbbell-shaped Janus co-cluster. In a mixed solvent of acetonitrile and water, it self-assembles into a crystal with a honeycomb superstructure constructed by hexagonal close-packed cylinders of the smaller cluster and an orderly arranged framework of the larger cluster. Reconstruction of these structural features via coarse-grained molecular simulations demonstrates that the cluster crystallization and the nanoscale phase separation between the two incompatible clusters synergistically result in the unique nano-architecture. Overall, this work opens up new opportunities for generating novel CAMs for advanced future applications.