Angewandte Chemie, Accepted Article.
Spatial organization of electron donor‐acceptor (D‐A) supramolecular assembly is critical to the photophysical processes involved in solar energy conversion systems. Subtle variation in geometry, i.e. D‐A distance and transition dipole arrangement can influence kinetics and thermodynamics of the electron transfer (ET) process. To acquire an insight into the structure‐function correlation, making of modular, crystalline materials is advantageous. In this regard, we demonstrate a redox‐active, crystalline D‐A assembly, in which ET process can be reversibly switched. This ET process, induced by a guest‐responsive structural transformation at room temperature, is realized in a porous, metal‐organic framework (MOF), having anthracene (D) – naphthalenediimide (A) as struts. A control MOF structure obtained by solvent‐assisted linker exchange (SALE) method, replacing acceptor strut with a neutral one, supported the switchable electronic states in D‐A MOF. Combined investigations with X‐ray diffraction, spectroscopic and theoretical analyses revealed the dynamic metal paddle‐wheel node as a critical unit for controlling structural flexibility and corresponding unprecedented ET process.