Hyperpolarized 129Xe NMR investigation of multifunctional organic/inorganic hybrid mesoporous silica materials

Shing Jong Huang, Seong Huh, Pang Shueng Lo, Shou-Heng Liu, Victor S.Y. Lin, Shang Bin Liu

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

An extensive study has been made on a series of multifunctional mesoporous silica materials, prepared by introducing two different organoalkoxysilanes, namely 3-[2-(2-aminoethylamino)ethylamino] propyltrimethoxysilane (AEPTMS) and 3-cyanopropyltriethoxysilane (CPTES) during the base-catalyzed condensation of tetraethoxysilane (TEOS), using the variable-temperature (VT) hyperpolarized (HP) 129Xe NMR technique. VT HP-129Xe NMR chemical shift measurements of adsorbed xenon revealed that surface properties as well as functionality of these AEP/CP-functionalized microparticles (MP) could be controlled by varying the AEPTMS/CPTES ratio in the starting solution during synthesis. Additional chemical shift contribution due to Xe-moiety interactions was observed for monofunctional AEP-MP and CP-MP as well as for bifunctional AEP/ CP-MP samples. In particular, unlike CP-MP that has a shorter organic backbone on the silica surface, the amino groups in the AEP chain tends to interact with the silanol groups on the silica surface causing backbone bending and hence formation of secondary pores in AEP-MP, as indicated by additional shoulder peak at lower field in the room-temperature 129Xe NMR spectrum. The exchange processes of xenon in different adsorption regions were also verified by 2D EXSY HP-129Xe NMR spectroscopy. It is also found that subsequent removal of functional moieties by calcination treatment tends to result in a more severe surface roughness on the pore walls in bifunctional samples compared to monofunctional ones. The effect of hydrophobicity/ hydrophilicity of the organoalkoxysilanes on the formation, pore structure and surface property of these functionalized mesoporous silica materials are also discussed.

Original languageEnglish
Pages (from-to)3080-3087
Number of pages8
JournalPhysical Chemistry Chemical Physics
Volume7
Issue number16
DOIs
Publication statusPublished - 2005 Aug 21

Fingerprint

microparticles
Silicon Dioxide
Nuclear magnetic resonance
silicon dioxide
nuclear magnetic resonance
Xenon
Chemical shift
Surface properties
porosity
xenon
surface properties
chemical equilibrium
Hydrophilicity
Hydrophobicity
Pore structure
Calcination
Temperature
Nuclear magnetic resonance spectroscopy
Condensation
Surface roughness

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Huang, Shing Jong ; Huh, Seong ; Lo, Pang Shueng ; Liu, Shou-Heng ; Lin, Victor S.Y. ; Liu, Shang Bin. / Hyperpolarized 129Xe NMR investigation of multifunctional organic/inorganic hybrid mesoporous silica materials. In: Physical Chemistry Chemical Physics. 2005 ; Vol. 7, No. 16. pp. 3080-3087.
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Hyperpolarized 129Xe NMR investigation of multifunctional organic/inorganic hybrid mesoporous silica materials. / Huang, Shing Jong; Huh, Seong; Lo, Pang Shueng; Liu, Shou-Heng; Lin, Victor S.Y.; Liu, Shang Bin.

In: Physical Chemistry Chemical Physics, Vol. 7, No. 16, 21.08.2005, p. 3080-3087.

Research output: Contribution to journalArticle

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