Mechanism of Macroscopic Motion of Oleate Helical Assemblies: Cooperative Deprotonation of Carboxyl Groups Triggered by Photoisomerization of Azobenzene Derivatives |
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Authors: | Dr Yoshiyuki Kageyama Tomonori Ikegami Yuta Kurokome Prof?Dr Sadamu Takeda |
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Institution: | 1. Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Japan), Fax: (+81)?11?706?4841;2. JST PRESTO, Kawaguchi, 332-0012 (Japan);3. Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Japan |
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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. |
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Keywords: | helical structures isomerization molecular devices photochemistry supramolecular chemistry |
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