Metal–Organic Rotaxane Frameworks: Three‐Dimensional Polyrotaxanes from Lanthanide‐Ion Nodes, Pyridinium N‐Oxide Axles, and Crown‐Ether Wheels

Circles cubed: The title materials can be prepared by self-assembly and are similar to conventional metal–organic framework materials, but with every linker being a [2]rotaxane made from pyridinium axles and crown-ether wheels (see structures; left: a single “cube” unit of the 3D network with the crown-ether wheels removed, right: the same framework with crown-ether wheels included; Sm ions gold).