Improved resolution in proton-detected heteronuclear long-range correlation

H. Kessler, P. Schmieder, M. Koeck, M. Kurz

J. Magn. Reson. (1990) 88, 615-618

A comparison is presented between a normal HMBC NMR experiment, recorded with a spectral window of 200 ppm in the proton dimension (F1), with 2 semiselective HMBC experiments, showing only the aromatic region in F1, recorded with 90° and 270° Gaussian pulses, respectively. The pulse sequences used are shown. Illustrative spectra of a cyclic hexapeptide are presented. The advantage of a semiselective experiment is apparent, and the advantage of the 270°Gaussian pulse is clearly demonstrated.