## Abstract A series of model tertiary amines were oxidized __in situ__ in an NMR tube to amine __N__‐oxides and their ^1^H and ^13^C NMR spectra were recorded. Next, the chemical shifts induced by oxidation (Δδ) were calculated using different GIAO methods investigating the influence of the method
Observed and calculated 1H and 13C chemical shifts induced by the in situ oxidation of model sulfides to sulfoxides and sulfones
✍ Scribed by Martin Dračínský; Radek Pohl; Lenka Slavětínská; Miloš Buděšínský
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 322 KB
- Volume
- 48
- Category
- Article
- ISSN
- 0749-1581
- DOI
- 10.1002/mrc.2658
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✦ Synopsis
Abstract
A series of model sulfides was oxidized in the NMR sample tube to sulfoxides and sulfones by the stepwise addition of meta‐chloroperbenzoic acid in deuterochloroform. Various methods of quantum chemical calculations have been tested to reproduce the observed ^1^H and ^13^C chemical shifts of the starting sulfides and their oxidation products. It has been shown that the determination of the energy‐minimized conformation is a very important condition for obtaining realistic data in the subsequent calculation of the NMR chemical shifts. The correlation between calculated and observed chemical shifts is very good for carbon atoms (even for the ‘cheap’ DFT B3LYP/6‐31G* method) and somewhat less satisfactory for hydrogen atoms. The calculated chemical shifts induced by oxidation (the Δδ values) agree even better with the experimental values and can also be used to determine the oxidation state of the sulfur atom (S, SO, SO~2~). Copyright © 2010 John Wiley & Sons, Ltd.
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