✦ LIBER ✦
The tetramethylammonium ion (TMA+) versus the hydronium ion (H3O+) as internal reference for 1H NMR measurements in superacid media. Solute–solvent interactions
✍ Scribed by Paul Rimmelin; Sylvie Schwartz; Jean Sommer
- Publisher
- John Wiley and Sons
- Year
- 1981
- Tongue
- English
- Weight
- 326 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
Abstract
It is shown that the chemical shift of the generally utilized internal reference for ^1^H NMR measurements in superacid media, namely, tetramethylammonium bromide, which is normally fixed at 3.10 ppm from external TMS, changes with the composition of the acid mixture (HF or HSO~3~F:SbF~5~). This is attributed to solute–solvent interactions. The use of both the tetramethylammonium ion or the hydronium ion as internal references is discussed, as the hydronium ion appears to be only slightly influenced by these interactions.