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

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

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
Volume57
Issue number1
DOIs
Publication statusPublished - 2011 Jan 1

Keywords

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

ASJC Scopus subject areas

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

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