Face‐Directed Assembly of Molecular Cubes: In Situ Substitution of a Predetermined Concave Cluster

Systematic design and self-assembly of metal-organic polyhedra with predictable configuration has been a long-standing challenge in crystal engineering due to the difficulty of finding suitable building units. Herein, we are focused on a concave polyoxovanadate cluster [V6O6(OCH3)9(SO4)4]5- that can be generated in situ under the exact reaction conditions. Based on this cluster, a potential trivalent molecular building block [V6O6(OCH3)9(SO4)(CO2)3]2- can be obtained by the bridging-ligand-substitution strategy that possesses appropriate angle information for the design of molecular cubes. Utilizing the face-directed assembly of the trivalent molecular building block and a diverse set of tetratopic carboxylate linkers, a series of metal-organic cubes VMOC-1 to VMOC-5 with the same topology but different functionalities and dimensions are designed and constructed. The inclusion study made with VMOC-3 as an example has shown that they are potential molecular receptors and can selectively capture size-matching polycyclic aromatic hydrocarbon guest molecules.