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1 H chemical shifts in NMR: Part 23, the effect of dimethyl sulphoxide versus chloroform solvent on 1 H chemical shifts
Author(s) -
Abraham Raymond J.,
Byrne Jonathan J.,
Griffiths Lee,
Perez Manuel
Publication year - 2006
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.1747
Subject(s) - chemistry , chemical shift , solvent , chloroform , solvent effects , dihedral angle , hydrogen bond , computational chemistry , molecule , organic chemistry
The 1 H chemical shifts of 124 compounds containing a variety of functional groups have been recorded in CDCl 3 and DMSO‐ d 6 (henceforth DMSO) solvents. The 1 H solvent shift Δδ = δ(DMSO) − δ(CDCl 3 ) varies from −0.3 to +4.6 ppm. This solvent shift can be accurately predicted (rms error 0.05 ppm) using the charge model of α, β, γ and long‐range contributions. The labile protons of alcohols, acids, amines and amides give both, the largest solvent shifts and the largest errors. The contributions for the various groups are tabulated and it is shown that for H.C.C.X γ‐effects (X = OH, NH, O, NH.CO) there is a dihedral angle dependence of the γ‐effect. The group contributions are discussed in terms of the possible solvent–solute interactions. For protic hydrogens, hydrogen bonding is the dominant interaction, but for the remaining protons solvent anisotropy and electric field effects appear to be the major factors. Copyright © 2006 John Wiley & Sons, Ltd.