The recently introduced CLIP-COSY[1] experiment together with its relayed and double-relayed extension facilitating rapid acquisition of homonuclear correlation spectrum for the structure elucidation of small and medium-sized molecules, among them carbohydrates as well. However, the resolution of COSY spectra (even when recorded with high resolution) is limited by the inherently small chemical shift dispersion of proton resonances. To utilize the resolving power of heteronuclei offered by their superior chemical shift range, we designed an HSQC-variant of the CLIP-COSY experiment. The combined analysis of standard HSQC and HSQC-CLIP-COSY(relay) spectra enables the semi-automatic and simultaneous assignment of both 1H and 13C resonances resulting from an easy and straightforward step-by-step walk along the direct 13C-1H and the 13C-1H-1H relay peaks in the overlaid spectra.
T. Gyöngyösi, I. Timári, J. Haller. M. R. M. Koos , B. Luy, K. E. Kövér:
Boosting the NMR assignment of carbohydrates with clean in-phase correlation experiments
CHEMPLUSCHEM 83: 1 pp. 53-60, 8 p. (2018)