Metal-organic frameworks incorporating copper-complexed rotaxanes.

The incorporation of mechanically interlocked molecules (MIMs), such as rotaxanes and catenanes, into porous metal– organic frameworks (MOFs) has recently been recognized as a strategy for introducing dynamics into otherwise rigid, robust frameworks. In this manner, the interlocked nature of these switchable components allows dynamics to be expressed independently of the MOF backbone and, therefore, without compromising the fidelity of the whole system. Accordingly, p-electron-rich crown ethers, capable of binding p-electrondeficient substrates, and degenerate donor–acceptor [2]catenanes have already been introduced into MOFs. In addition, [2]rotaxanes, wherein the dumbbell components function as struts in the frameworks, have also been incorporated into MOFs. While this strategy has been applied to the preparation of a number of 2D and 3D frameworks from [2]pseudorotaxanate subunits, it remains a challenge to locate switchable rotaxanes and catenanes inside extended frameworks. Metal-containing MIMs—particularly those based on the well-known copper(I)-templated systems—offer the opportunity to locate switches within MOFs. Herein, we