Premium
Electronic influences on 3 J (C,H) coupling constants via S, S(O) and SO 2 : their determination, calculation and comparison of detection methods
Author(s) -
Heydenreich Matthias,
Koch Andreas,
Kovács József,
Tóth Gábor,
Kleinpeter Erich
Publication year - 2004
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.1398
Subject(s) - chemistry , coupling constant , series (stratigraphy) , coupling (piping) , sulfur , sulfoxide , hydrogen atom , computational chemistry , carbon 13 , carbon fibers , range (aeronautics) , sulfone , stereochemistry , quantum mechanics , organic chemistry , physics , biology , mechanical engineering , paleontology , materials science , composite number , engineering , composite material , alkyl
3 J (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 sp 3 carbon, and an sp 2 carbon is treated; the second series ( 4 – 6 ) deals with the coupling between a hydrogen, bonded to an sp 3 carbon, and an sp 3 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 3 J (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 3 J (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 3 J (C,H) coupling constants. Copyright © 2004 John Wiley & Sons, Ltd.