A metallosupramolecular-based ring-in-ring complex showing reversible host–guest dynamics and switchable electrochemical properties

Studying reversible host-guest interactions is essential for developing flexible, efficient, and sustainable systems, as they enhance reusability, improve efficiency, and provide valuable insights for designing advanced materials and technologies. In this work, we describe the synthesis of a pyrene-naphthalenediimide-based heterocyclophane, which can be encapsulated in an iridium-cornered nanosized metallobox with a high binding affinity. Electrochemical studies of the resulting host-guest complex reveal that encapsulation significantly alters the cyclophane's redox behavior, with the processes being highly sensitive to guest uptake and release dynamics. Reduction of the cyclophane occurs at the naphthalenediimide (NDI) unit, generating a radical species that is stabilized upon encapsulation within the metallobox cavity. Host-guest dynamics were investigated using variable temperature ¹H NMR spectroscopy, and the release and uptake of the guest can be precisely controlled by adding chloride or silver(I) ions. We believe that our studies can help the development of methodologies to controllably allow the release and uptake of guests from metallosupramolecular assemblies, which are central to many of the applications of these systems.