Endohedral Coordination of Bulky Substrates in Metalloenzyme‐Like Organometallic Nanotubes

Abstract Artificial receptors inspired by metalloenzymes share three key properties: a structurally flexible cavity, substrate binding via metal‐ligand coordination, and metal‐based redox activity. Herein, we report an organometallic nanotube with such features based on our supramolecular pillarplex platform, incorporating eight Cu I centers in its cavitand walls. The structurally adaptable cavity of this receptor enables the endohedral coordination of tetrahydrofuran (THF) as a hydrophilic model substrate with remarkable binding affinity despite a steric mismatch between the host and guest. Evidence from SC‐XRD, 1 H NMR titration in aqueous solution, and DFT modelling confirms that metal‐ligand coordination governs substrate binding. Electrochemical analysis of a derived rotaxane reveals metal‐centered redox activity.