Structural conversions of host–guest systems and dynamic metal complexes for development of time-dependent functions

Abstract This article introduces the concept of dynamic structure-transforming molecules, a new class of functional molecules whose structures and functions gradually and controllably evolve over time. Unlike previous studies that focused only on the initial and final states of structural transformations, this research emphasizes the importance of intermediate states, including their response speeds and time profiles. One class involves host molecules with blocked apertures, where guest uptake and release are slowed down through structural modifications, such as bridging by diamine ligands or capping by anions. Another class utilizes helical structures with precisely tunable chirality inversion rates, influenced by guest binding, ligand exchange reactions, or chemical transformations in the modulator units. The third class involves host–guest systems coupled with chemical reactions, where guest binding occurs either before or after the reaction, and can be further accelerated by additives. These systems demonstrate unique, time-programmed functions, offering new directions for the design of smart materials and molecules with programmable behavior over time.