Host–guest supramolecular chemistry of carboranes: structural features and emerging applications in nanotechnology and nanomedicine

Carboranes are abiotic, polyhedral clusters containing boron, carbon and hydrogen atoms characterized by exceptional thermal and chemical stability, three-dimensional aromaticity, and unique electronic and structural features. Among them, carborane clusters containing two carbon atoms within the cage (dicarborane or C 2 -carboranes) represent a particularly important class, encompassing closo -dicarba-dodecaboranes, their nido derivatives, and related dicarbollide-based systems. In this review, we provide a comprehensive overview of the interactions between dicarboranes and a wide range of hosts, including macrocycles, molecular cages, nanostructured materials, and biomolecules. The analysis highlights the diverse non-covalent interactions governing complex formation, such as hydrophobic effects, C-H···π and B-H···π contacts, dihydrogen bonding, and electrostatic contributions, which enable strong and tunable binding affinities. Particular emphasis is placed on the relationship between structural features, such as isomer type, cage topology, and functionalization, and host–guest behavior. We discuss how the rigidity, globular shape, and modular functionalization of dicarboranes contribute to enhanced host–guest recognition and facilitate the design of supramolecular assemblies with controlled size, morphology, and responsiveness. Emerging applications in nanotechnology and nanomedicine are highlighted, including self-assembled nanoplatforms, stimuli-responsive delivery systems, sensing, molecular machines, self-healing materials, and bioactive systems. In biomedical contexts, carborane-based systems have attracted considerable attention as pharmacophores, as well as in boron neutron capture therapy, bioorthogonal labeling, intracellular carrier and protein targeting strategies. Overall, the unique physicochemical properties of carboranes, combined with their versatile supramolecular behavior, position them as powerful building blocks for next-generation functional materials. This review highlights the growing importance of carborane-based host–guest chemistry, while delineating key limitations and future opportunities for its integration into advanced technological and biomedical applications.