Regulating the Assembly of γ-Cyclodextrin Host and Polyoxometalate-Based Guests toward Light-Responsive Hybrid Rotaxanes
Wu‐Ji Chen, Chunyan Liu, Yun‐Jing Mu, Yian Yin, Chang‐Gen Lin, De‐Liang Long, Leroy Cronin, Yu‐Fei Song
Abstract
The rational design of hybrid organic–inorganic rotaxanes is crucial for advancing molecular machines and functional nanomaterials, yet the integration of metal-oxo clusters into interlocked systems remains challenging. Herein, we present a precision synthesis strategy for hybrid rotaxanes combining γ-cyclodextrin (γ-CD) hosts with Anderson-type polyoxometalate (POM)-based guests. This approach utilizes covalent POM modification coupled with strategically anchored organic functionalities to control supramolecular assembly, enabling the construction of pseudo -[2]-, [3]-, and [4]rotaxanes with controlled structural variations. Significantly, we achieved the first single-crystal examples of supramolecular pseudo -[4]rotaxanes featuring γ-CD dimers threaded by two organo-POM units. A key breakthrough was achieved through light-induced single-crystal-to-single-crystal transformation of these pseudo -[4]rotaxanes, producing hybrid [3]rotaxanes containing uniquely arranged anti -head-to-tail anthracene dimers─the first reported photoresponsive architecture of this type. These structural transformations demonstrate the dynamic, stimuli-responsive character of these hybrid systems. This work establishes a new paradigm for the precision engineering of rotaxanes using organo-POM building blocks, revealing their remarkable potential for creating smart materials with programmable structural changes. The successful integration of covalent modification, supramolecular templating, and photoresponsive components provides a powerful platform for developing next-generation multifunctional molecular machines and adaptive nanomaterials with precisely controlled properties.