title: Mechanism of Macroscopic Motion of Oleate Helical Assemblies: Cooperative Deprotonation of Carboxyl Groups Triggered by Photoisomerization of Azobenzene Derivatives.
abstract: Macroscopic and spatially ordered motions of self-assemblies composed of oleic acid and a small amount of an azobenzene derivative, induced by azobenzene photoisomerization, was previously reported. However, the mechanism of the generation of submillimeter-scale motions by the nanosized structural transition of azobenzene was not clarified. Herein, an underlying mechanism of the motions is proposed in which deprotonation of carboxyl groups in cooperation with azobenzene photoisomerization causes a morphological transition of the self-assembly, which in turn results in macroscopic forceful dynamics. The photoinduced deprotonation was investigated by potentiometric pH titration and FTIR spectroscopy. The concept of hierarchical molecular interaction generating macroscale function is expected to promote the next stage of supramolecular chemistry.
authors.affiliation: Department of Chemistry, Faculty of Science, Hokkaido University, North-10, West-8, Sapporo, 060-0810, Japan), Fax: (+81) 11 706 4841. 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: http://orcid.org/0000-0002-2287-832X
authors.initials: Y
authors.lastname: Kageyama
authors.affiliation: Graduate School of Chemical Sciences and Engineering, Hokkaido University, North-10, West-8, Sapporo, 060-0810, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Ikegami
authors.affiliation: Graduate School of Chemical Sciences and Engineering, Hokkaido University, North-10, West-8, Sapporo, 060-0810, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Kurokome
authors.affiliation: Department of Chemistry, Faculty of Science, Hokkaido University, North-10, West-8, Sapporo, 060-0810, Japan), Fax: (+81) 11 706 4841. stakeda@sci.hokudai.ac.jp.
authors.forename: Sadamu
authors.initials: S
authors.lastname: Takeda
keywords: helical structures; isomerization; molecular devices; photochemistry; supramolecular chemistry