2025-06-062025-06-062025-04-16Fernández Clavero, C., Rivero Barbarroja, G., Carmona, T., García Iriepa, C., Marcelo, G., Tros de Ilarduya, C.,...,Mendicuti, F. (2025). Light-controlled assembly and disassembly of cyclodextrin-bisazobenzene supramolecular complexes. European Polymer Journal, 229, 113849. https://doi.org/10.1016/j.eurpolymj.2025.113849.1873-19450014-3057https://hdl.handle.net/11441/174043The inclusion complexation of a water soluble bis-azobenzene derivative (bis-Azo) and its monotopic analog (mono-Azo) with α-, β-, and γ-cyclodextrins (CyDs) was investigated as a prototype for light-responsive selfassembling systems. Using spectroscopic techniques (UV–vis, induced circular dichroism, 1 H NMR), computational methods (molecular mechanics and dynamics), and thermodynamic analyses, we examined the photoswitching properties, stability, and structural dynamics of these systems. The azobenzene moieties in the Eisomer of mono-Azo and bis-Azo consistently showed strong affinity for the αCyD cavity, characterized by high association constants. In contrast, no complex formation was observed upon photoinduced E-to-Z isomerization. For bis-Azo, this implies the formation of supramolecular αCyD dimers, with the spatial separation between the oppositely oriented host components determined by the connector linking the two azobenzene moieties in the Econfigured ditopic guest. This complex disassembles upon photoswitching, driven by the structural disruption associated with the Z-form. Both the E-and Z-isomers fitted in the cavity of βCyD, with moderate selectivity towards the E-form. A similar scenario was found for complexes with γCyD when using low concentrations of the host. Interestingly, at high concentrations γCyD formed low-solubility pseudopolyrotaxane-type supramolecular architectures with bis-Azo, which were disrupted upon Z-isomer photoisomerization. All the complexes demonstrated high fatigue resistance, maintaining structural integrity after multiple isomerization cycles. This work advances the design of stimuli-responsive preorganized supramolecular systems, with potential applications in nucleic acid delivery through dual pH/light-sensitive mechanisms.application/pdf15 p.engAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/AzobenzeneCyclodextrinsHost-Guest assembliesPseudopolyrotaxanesCircular DichroismMolecular Dynamicsinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccess10.1016/j.eurpolymj.2025.113849