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Observed and calculated 1 H and 13 C chemical shifts induced by the in situ oxidation of model sulfides to sulfoxides and sulfones
Author(s) -
Dračínský Martin,
Pohl Radek,
Slavětínská Lenka,
Buděšínský Miloš
Publication year - 2010
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.2658
Subject(s) - chemistry , chemical shift , sulfur , quantum chemical , hydrogen , chemical reaction , computational chemistry , hydrogen atom , molecule , organic chemistry , group (periodic table)
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.