Observation of hydroxyl groups by 17O solid-state multiple quantum MAS NMR in sol–gel-produced silica
✍ Scribed by E.R.H van Eck; M.E Smith; S.C Kohn
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 158 KB
- Volume
- 15
- Category
- Article
- ISSN
- 0926-2040
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✦ Synopsis
17
Ž
. O NMR parameters C , h, d and T are reported for both Si-O-Si and Si-OH fragments within a silica gel. The Q i s o 1 Ž . Si-OH units have a wide spread of parameters but are typically characterised by a very short T ; 0.1 ms and C -200 1 Q kHz. These observations have extremely important implications for the quantification of such units in these gels and related glassy materials by 17 O NMR. In light of these observations, the 17 O NMR experiments have been optimised and a distinct Ž . resonance from the OH group is observed in 1D static and magic angle spinning MAS NMR measurements as well in the Ž . multiple quantum MQ experiment.