2 J HH-resolved HSQC: Exclusive determination of geminal proton-proton coupling constants]]>

摘要

Graphical abstract A 2 J HH-resolved HSQC experiment for the exclusive and accurate determination of the magnitude of 2 J HH from the doublet displayed along the highly-resolved indirect F1 dimension is described. A pragmatic 2 J HH NMR profile affords a fast overview of the full range of existing 2 J HH values. In addition, a 2 J HH/δ(13C)-scaled version proves to be an efficient solution when severe overlapped signals complicate a rigorous analysis. The performance of the method is evaluated and compared with other current techniques and illustrated by determining residual dipolar 2 D HH coupling constants of small molecules dissolved in weakly orienting media. Display Omitted Highlights ? A J-resolved experiment to measure of two-bond proton-proton coupling constants. ? In-situ determination of two-bond proton-proton RDCs in anisotropic media. ? Direct measurement of proton-proton RDCs in equivalent CH2 spin systems. ? 2DHH are complementaries to 1DCH in RDC-assisted structural discrimination studies. Abstract The measurement of two-bond proton-proton coupling constants (2 J HH) in prochiral CH2 groups from the F2 dimension of 2D spectra is not easy due to the usual presence of complex multiplet J