Synthesis and crystal structure of double-three ring (D3R)-type cage siloxanes modified with dimethylsilanol groups

Naoto Sato, Kazuma Tochigi, Yoshiyuki Kuroda, Hiroaki Wada, Atsushi Shimojima, Kazuyuki Kuroda

    研究成果: Article

    3 被引用数 (Scopus)

    抄録

    The controlled assembly of molecular building blocks enables the rational design of nanomaterials. In this study, two types of cage-type oligosiloxanes with double-three ring (D3R) structures are modified with dimethylsilanol groups to form supramolecular assemblies. One is the siloxane cage derived from Si(OEt) 4 (denoted as the Q 6 cage), and the other is the organosiloxane cage derived from (EtO) 3 Si-CH 2 -Si(OEt) 3 (denoted as the T 6 cage). The syntheses of the silanol-modified cages are performed in two steps: (i) dimethylsilylation of the corner Si-O groups on the Q 6 and T 6 cages to introduce Si-H groups and (ii) subsequent oxidation of the Si-H groups to Si-OH groups. Dimethylsilylation of the cages is conducted at much lower temperatures (−94 and −78 °C for Q 6 and T 6 cages, respectively) than those used for conventional silylation, which is the key to suppressing the deterioration of the unstable D3R structure. The subsequent oxidation of the Si-H groups proceeds successfully, and the crystallization of these molecules is induced by the hydrogen bonds of the silanol groups. The crystal structure of the Q 6 cage modified with dimethylsilanol groups can be regarded as a layered structure with tetrahydrofuran between the layers. In contrast, the T 6 cage modified with dimethylsilanol groups assembled to form a more densely packed structure with no included solvent molecules. The differences between the crystal structures are discussed in terms of the shape of the cages. The insight into the effect of the shape of the cage on its assembly behavior will lead to the designable synthesis of crystalline siloxane-based materials.

    本文言語English
    ページ(範囲)1969-1975
    ページ数7
    ジャーナルDalton Transactions
    48
    6
    DOI
    出版ステータスPublished - 2019 1 1

    ASJC Scopus subject areas

    • Inorganic Chemistry

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