Electronic influences on 3J(C,H) coupling constants via -S-, -S(O)- and -SO2-: their determination, calculation and comparison of detection methods

Matthias Heydenreich; Andreas Koch; József Kovács; Gábor Tóth; Erich Kleinpeter

doi:10.1002/mrc.1398

Electronic influences on 3J(C,H) coupling constants via -S-, -S(O)- and -SO2-: their determination, calculation and comparison of detection methods

Magn Reson Chem. 2004 Aug;42(8):667-70. doi: 10.1002/mrc.1398.

Authors

Matthias Heydenreich¹, Andreas Koch, József Kovács, Gábor Tóth, Erich Kleinpeter

Affiliation

¹ Chemisches Institut der Universität Potsdam, P.O. Box 69 15 53, D-14415 Potsdam, Germany.

PMID: 15248254
DOI: 10.1002/mrc.1398

Abstract

3J(C,H) coupling constants via a sulfur atom in two series of compounds, both including a sulfide, a sulfoxide and a sulfone, were detected experimentally and calculated by quantum mechanical methods. In the first series (1-3) the coupling between a hydrogen, bonded to an sp3 carbon, and an sp2 carbon is treated; the second series (4-6) deals with the coupling between a hydrogen, bonded to an sp3 carbon, and an sp3 carbon. Different pulse sequences (broadband HMBC, SelJres, 1D HSQMBC, J-HMBC-2, selective J-resolved long-range experiment and IMPEACH-MBC) proved to be useful in determining the long-range 3J(C,H) coupling constants. However, the dynamic behaviour of two of the compounds (4 and 6) led to weighted averages of the two coupling constants expected (concerning equatorial and axial positions of the corresponding hydrogens). DFT calculations proved to be useful to calculate not only the 3J(C,H) coupling constants but also the different contributions of FC, PSO, DSO and SD terms; the calculation of the Fermi contact term (FC) was found to be sufficient for the correct estimation of 3J(C,H) coupling constants.