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A Shuttling Molecular Machine with Reversible Brake Function
Author(s) -
Hirose Keiji,
Shiba Yoshinobu,
Ishibashi Kazuaki,
Doi Yasuko,
Tobe Yoshito
Publication year - 2008
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.200702001
Subject(s) - rotaxane , molecular machine , axle , ring (chemistry) , component (thermodynamics) , brake , dumbbell , ammonium , chemistry , catenane , materials science , molecule , nanotechnology , organic chemistry , physics , mechanical engineering , engineering , medicine , physical therapy , metallurgy , thermodynamics , supramolecular chemistry
Design, synthesis, and demonstration of a prototype of a shuttling molecular machine with a reversible brake function are reported. It is a photochemically and thermally reactive rotaxane composed of a dianthrylethane‐based macrocycle as the ring component and a dumbbell shaped molecular unit with two, secondary ammonium stations separated by a phenylene spacer as the axle component. The rate of shuttling motion was shown to be reduced to less than 1 % (from 340 to <2.5 s −1 ) by reducing the size of the ring component from 30‐crown‐8 to 24‐crown‐8 macrocycles upon photoirradiation. The ring component was turned back to 30‐crown‐8 by thermal ring opening, thus establishing a reversible brake function that works in response to photochemical and thermal stimuli.