title: Dissipative and Autonomous Square-Wave Self-Oscillation of a Macroscopic Hybrid Self-Assembly under Continuous Light Irradiation.
abstract: Building a bottom-up supramolecular system to perform continuously autonomous motions will pave the way for the next generation of biomimetic mechanical systems. In biological systems, hierarchical molecular synchronization underlies the generation of spatio-temporal patterns with dissipative structures. However, it remains difficult to build such self-organized working objects via artificial techniques. Herein, we show the first example of a square-wave limit-cycle self-oscillatory motion of a noncovalent assembly of oleic acid and an azobenzene derivative. The assembly steadily flips under continuous blue-light irradiation. Mechanical self-oscillation is established by successively alternating photoisomerization processes and multi-stable phase transitions. These results offer a fundamental strategy for creating a supramolecular motor that works progressively under the operation of molecule-based machines.
authors.affiliation: Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, 060-0810, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Ikegami
authors.affiliation: Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan. y.kageyama@mail.sci.hokudai.ac.jp.|JST PRESTO, Kawaguchi, 332-0012, Japan. y.kageyama@mail.sci.hokudai.ac.jp.
authors.forename: Yoshiyuki
authors.identifier: 0000-0002-2287-832X
authors.initials: Y
authors.lastname: Kageyama
authors.affiliation: Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Obara
authors.affiliation: Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan. stakeda@sci.hokudai.ac.jp.
authors.forename: Sadamu
authors.initials: S
authors.lastname: Takeda
keywords: cooperative effects; molecular devices; non-equilibrium processes; phase transitions; photochromism