Discrete Stimuli‐Responsive Multirotaxanes with Supramolecular Cores Constructed through a Modular Approach

The synthesis of discrete multirotaxanes with well‐defined structures remains a great challenge. Herein, we present the successful construction of diverse discrete multirotaxanes with well‐defined supramolecular metallacycles as cores by a modular approach. Moreover, these novel multirotaxanes featured a stimuli‐responsive property that enabled the introduction and removal of the bromide anion by taking advantage of dynamic nature of the supramolecular metallacycle scaffold. Through the combination of rotaxane‐containing prefunctionalized building blocks with the corresponding different organoplatinum(II) acceptor building blocks (60, 120, or 180°), diverse discrete multirotaxanes with well‐defined metallacycles (rhomboid or hexagon) as cores as well as certain numbers of rotaxane units were successfully obtained quantitatively by means of coordination‐driven self‐assembly. Furthermore, owing to the existence of a dynamic metallacycle as the supramolecular cores, the resultant multirotaxanes showed anion‐induced disassembly and reassembly properties, which allowed for the reversible transformation between multirotaxanes and the corresponding individual rotaxane‐containing building blocks. Therefore, this research not only enriches the family of discrete multirotaxanes, but also provides a novel strategy for the construction of “smart” stimuli‐responsive multirotaxane systems.