Adaptive Self‐Assembly and Induced‐Fit Interconversions between Molecular Borromean Rings, Russian Dolls and Ring‐in‐Ring Complexes †

Main observation and conclusion Herein, we report an artificially assembled interlocked system that features adaptive self‐assembly and induced‐fit transformation properties in the presence of appropriate guest molecules. By careful choice of solvent and guests, a molecular Borromean rings complex based on organometallic half‐sandwich units could be transformed in a stepwise manner to a ring‐in‐ring complex and a monomeric rectangle, leading to a conversion cycle between these structures. This adaptive self‐assembly method was further applied to the construction of a Russian dolls complex, forming another conversion cycle composed of a molecular Borromean rings complex, a Russian dolls complex and a monomeric rectangle. A comprehensive map showing all of the structural transformations between these metallarectangles and interlocked species is drawn up, representing a recoverable and recyclable transformation mechanism.