Nucleophilic substitution on silica surfaces

Autor(en)

Miriam Keppeler, Juergen Holzbock, Johanna Akbarzadeh, Herwig Peterlik, Nicola Huesing

Abstrakt

Azido-group functionalized, hierarchically organized meso-/macroporous silica gels have been prepared through co-condensation of tetrakis(2-hydroxyethyl)orthosilicate with chloromethyltrimethoxysilane or 3-(chloropropyl)-triethoxysilane and subsequent conversion of the chloro groups. Azido functionalities have been obtained by nucleophilic substitution of the surface-bound chloro moieties with NaN

₃ in N,N-dimethylformamide. A strong dependence of the later azide density (N

₃ groups nm

^-2) in the final material on the reaction conditions, such as temperature and time, but also on the spacer length (methylene versus propyl) of the organofunctional silane has been observed. In principle, the nucleophilic substitution benefits from higher reaction temperatures and times. However, while γ-azido groups seem to be stable over a wide range of reaction temperatures and longer reaction times, α-azido moieties tend to decompose at temperatures above 60°C. The structural features of the monolithic gels and the azide functionalities on the surface were determined by IR-ATR-spectroscopy, elemental analyses, N

₂-sorption analyses, small angle X-ray scattering and transmission electron microscopy.

Organisation(en)

Dynamik Kondensierter Systeme

Externe Organisation(en)

Universität Ulm, Paris-Lodron Universität Salzburg

Journal

Journal of the Ceramic Society of Japan

Band

123

Seiten

764-769

Anzahl der Seiten

6

ISSN

1882-0743

DOI

https://doi.org/10.2109/jcersj2.123.764

Publikationsdatum

09-2015

Peer-reviewed

Ja

ÖFOS 2012

103018 Materialphysik

Schlagwörter

ASJC Scopus Sachgebiete

Condensed Matter Physics, Ceramics and Composites, Materials Chemistry, Chemistry(all)

Link zum Portal

https://ucris.univie.ac.at/portal/de/publications/nucleophilic-substitution-on-silica-surfaces(32ed063b-6361-42a4-a038-1fc279906c28).html