Heterometallic‐organic cages with customized cavities: constructed by bottom‐up step‐wise coordination‐driven self‐assembly

Accurately synthesizing coordination‐driven metal‐organic cages with customized shape and cavity remains a great challenge for chemists. In this work, a bottom‐up step‐wise coordination‐driven self‐assembly approach was put forward. Employing this strategy, three terpyridyl heterometallic‐organic truncated tetrahedral cages with different sizes and cavity were precisely synthesized. Firstly, the coordination of tripodal organic ligands with Ru 2+ afforded dendritic metal‐organic ligands L1‐L3 . Then the Ru building blocks complexed with Fe 2+ and shrunk to form the desired heterometallic‐organic cages ( C1‐C3) . These discrete heterometallic‐organic supramolecular cages were fully characterized and displayed the large and open cavities varied from 7205 Å 3 to 9384 Å 3 . Notably, these cages could not be directly constructed by single‐step assembly process using initial organic ligands or dimeric metal‐organic ligands, indicative of the irreplaceability of a bottom‐up step‐wise assembly strategy for size‐customized architectures. This work paves a new way for precisely constructing metal‐organic cages with well‐defined cavities.