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Accordion‐Like Motion in Electrochemically Switchable Crown Ether/Ammonium Oligorotaxanes
H.V. Schröder, F. Stein, J.M. Wollschläger, S. Sobottka, M.Gaedke, B. Sarkar, C.A. Schalley – 2019
Reversible oxidation reactions in electrochemically switchable oligorotaxanes with tetrathiafulvalene (TTF) decorated 24‐crown‐8 ether wheels generate intramolecular mixed‐valence and radical‐cation interactions between the wheels. This induces shuttling of the wheels and a contraction of inter‐wheel distances. Further oxidation generates repulsive forces between the TTFs and maximizes the inter‐wheel distances instead. These interactions and co‐conformational changes were not observed for structurally similar controls in which acetyl groups along the axle prevent the wheels' translational motion. This novel operation mode of oligorotaxanes—reminiscent of an accordion‐like motion—is promising for functional materials and nanodevices such as piston‐type rotaxane motors.
Accordion‐Like Motion in Electrochemically Switchable Crown Ether/Ammonium Oligorotaxanes