Premium
Redox‐Switchable Calix[6]arene‐Based Isomeric Rotaxanes
Author(s) -
Zanichelli Valeria,
Bazzoni Margherita,
Arduini Arturo,
Franchi Paola,
Lucarini Marco,
Ragazzon Giulio,
Secchi Andrea,
Silvi Serena
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201800496
Subject(s) - calixarene , axle , redox , electrochemistry , chemistry , molecular machine , displacement (psychology) , supramolecular chemistry , combinatorial chemistry , stereochemistry , materials science , nanotechnology , molecule , electrode , organic chemistry , physics , psychology , psychotherapist , thermodynamics
Operating molecular machines are based on switchable systems whose components can be set in motion in a controllable fashion. The presence of nonsymmetrical elements is a mandatory requirement to obtain and demonstrate the unidirectionality of motion. Calixarene‐based macrocycles have proved to be very efficient hosts in the design of oriented rotaxanes and of pseudorotaxanes with strict control over the direction of complexation. A series of two‐station rotaxanes based on bipyridinium–ammonium axles was synthesized and characterized. A recently reported supramolecularly assisted strategy for the synthesis of different orientational isomers was exploited, and the ammonium unit was identified as a proper secondary station for the calixarene. Displacement of the macrocycle was triggered by electrochemical reduction of the bipyridinium primary station, and it was shown that the shuttling is influenced both by the length of the chain of the axle component and by the position of the secondary station with respect to the calixarene rims.