ISSN:
1573-4846
Schlagwort(e):
precursor chemistry
;
hydrolysis
;
condensation
;
solution NMR
;
solid state NMR
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
Notizen:
Abstract Hydrolysis and condensation reactions of four organically modified alkoxides, used for the preparation of silicon oxycarbide gel precursors, have been followed by 29Si NMR. Triethoxysilane (HSi(OEt)3) and methyldiethoxysilane (MeHSi(OEt)2) react extremely fast compared to methyltriethoxysilane (MeSi(OEt)3) and tetraethoxysilane (Si(OEt)4). Co-hydrolysis reactions between different pairs of precursors—MeSi(OEt)3/Si(OEt)4; MeSi(OEt)3/HSi(OEt)3; MeHSi(OEt)2/Si(OEt)4; and MeHSi(OEt)2/HSi(OEt)3—were investigated by solution state 29Si and 17O NMR. Despite significantly different reactivities between precursors, evidence for co-condensation reactions has been found for each system. Finally, two-dimensional 29Si-1H heteronuclear correlation MAS-NMR spectroscopy was used to probe the local environments of the various Si sites in the product hybrid networks.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1023/A:1008651221693
Permalink
