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Sequential and Time-Controlled Sol–Gel Transitions by Mechanical Switching of Molecular Tweezers

2025/01/28 by Pablo Msellem, Geoffrey Groslambert, Louise Miton +4 · 1 voice
Chemistry · Materials Science · Neuroscience · #Photoreceptor and optogenetics research #Supramolecular Chemistry and Complexes #Supramolecular Self-Assembly in Materials

paper · doi:10.1021/jacs.4c17146

openalex publication_date 2025/01/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/27

Abstract

Controlling the motion of molecular machines to influence higher-order structures is well-established in biological systems but remains a significant challenge for synthetic analogs. Herein, we aim to harness the mechanical switching of switchable molecular tweezers to modulate their self-assembly and produce stimuli-responsive organogels. We report a series of terpy(Pt-salphen) 2 molecular tweezers functionalized with alkyl chains that act as low-molecular-weight gelators (LMWGs) in their open conformation. The resulting organogels were thoroughly characterized by SEM, cryo-TEM, SAXS, and rheology. The macroscopic transition from gel to solution was achieved by the cation-induced closing of the tweezers, which triggers their substantial structural reorganization. Reversible sol–gel transitions were achieved through the sequential addition of chemical stimuli or by a decomposable acid in a time-controlled operation. Such transient disassembly process regulated by a chemical fuel enables multiple gelation cycles with minimal waste while maintaining stable rheological properties. These results underscore the potential of switchable molecular tweezers in creating advanced stimuli-responsive materials.

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