Rational Design of Nanofibers and Nanorings through Complementary Hydrogen-Bonding Interactions of Functional π Systems

Authors

  • Shiki Yagai Prof. Dr.,

    1. Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan), Fax: (+81) 43-290-3039
    2. PRESTO (Japan) Science and Technology Agency (JST), 4-1-8 Honcho Kawaguchi, Saitama (Japan)
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  • Hiroaki Aonuma,

    1. Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan), Fax: (+81) 43-290-3039
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  • Yoshihiro Kikkawa Dr.,

    1. Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan)
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  • Shun Kubota,

    1. Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan), Fax: (+81) 43-290-3039
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  • Takashi Karatsu Prof. Dr.,

    1. Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan), Fax: (+81) 43-290-3039
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  • Akihide Kitamura Prof. Dr.,

    1. Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan), Fax: (+81) 43-290-3039
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  • Sankarapillai Mahesh,

    1. Photosciences and Photonics Group, Chemical Science and Technology Division, National Institute for Interdisciplinary Science and Technology (NIIST), CSIR, Trivandrum-695019 (India), Fax: :(+91) 471-249-0186
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  • Ayyappanpillai Ajayaghosh Dr.

    1. Photosciences and Photonics Group, Chemical Science and Technology Division, National Institute for Interdisciplinary Science and Technology (NIIST), CSIR, Trivandrum-695019 (India), Fax: :(+91) 471-249-0186
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Abstract

A simple protocol to create nanofibers and -rings through a rational self-assembly approach is described. Whereas the melamine–oligo(p-phenylenevinylene) conjugate 1 a self-aggregates to form ill-defined nanostructures, conjugate 1 b, which possesses an amide group as an additional interactive site, self-aggregates to form 1D nanofibers that induce gelation of the solvent. AFM and XRD studies have shown that dimerization through the melamine–melamine hydrogen-bonding interaction occurs only for 1 b. Upon complexation with 1/3 equivalents of cyanuric acid (CA), conjugate 1 a provides well-defined, ring-shaped nanostructures at micromolar concentrations, which open to form fibrous assemblies at submillimolar concentrations and organogels in the millimolar concentration range. Apparently, the enhanced aggregation ability of 1 a by CA is a consequence of columnar organization of the resulting discotic complex 1 a3CA. In contrast, coaggregation of 1 b with CA does not provide well-defined nanostructures, probably due to the interference of complementary hydrogen-bonding interactions by the amide group.

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