title: A shuttling molecular machine with reversible brake function.
abstract: 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.
authors.affiliation: Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, Japan. hirose@chem.es.osaka-u.ac.jp
authors.forename: Keiji
authors.initials: K
authors.lastname: Hirose
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Shiba
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Ishibashi
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Doi
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Tobe