Hydrolysis behavior of a precursor for bridged polysilsesquioxane 1,4-bis(triethoxysilyl)benzene: A 29Si NMR study

Hitomi Saito, Yuki Nishio, Manabu Kobayashi, Yoshiyuki Sugahara

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    The hydrolysis behavior of 1,4-bis(triethoxysilyl)benzene (BTB), a precursor of bridged polysilsesquioxane, was investigated with high-resolution 29Si nuclear magnetic resonance (29Si NMR) spectroscopy at ambient temperature in a system with BTB:ethanol:water:HCl = 1:10:x:0.8 × 10-4 (x = 3, 6 or 9). Signals due to hydrolyzed triethoxysilyl groups as well as unhydrolyzed triethoxysilyl groups [-Si(OEt)3, -Si(OEt)2(OH), -Si(OEt)(OH)2 and -Si(OH)3 (OEt = OCH2CH3)] formed four sub-regions based on the number of hydroxyl groups bound to a silicon atom. In addition, one silicon environment influenced the other silicon environment by an intra-molecular interaction between two silicon atoms, and each sub-region for monomeric species thus contained four signals. Based on the development of signal intensity, it is revealed that one of the two triethoxysilyl groups in BTB is hydrolyzed preferentially. Thus, when a triethoxysilyl group is hydrolyzed, the -Si(OH) x (OEt)3-x (x = 1, 2) groups formed undergo further hydrolysis, which is opposite to the tendency expected from the hydrolysis behavior of organotrialkoxysilanes under acidic conditions.

    Original languageEnglish
    Pages (from-to)51-56
    Number of pages6
    JournalJournal of Sol-Gel Science and Technology
    Issue number1
    Publication statusPublished - 2011 Jan



    • Si NMR
    • Bridged polysilsesquioxane
    • Hydrolysis behavior
    • Intra-molecular interaction

    ASJC Scopus subject areas

    • Chemistry(all)
    • Condensed Matter Physics
    • Biomaterials
    • Ceramics and Composites
    • Electronic, Optical and Magnetic Materials
    • Materials Chemistry

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