LR-CAHSQC:: an application of a Carr-Purcell-Meiboom-Gill-type sequence to heteronuclear multiple bond correlation spectroscopy

A new pulse sequence, long-range CPMG-adjusted heteronuclear single quantum coherence (LR-CAHSQC), is proposed for the determination of long-range J(CH) coupling constants from a long-range H-1-C-13 correlation experiment. The long-range heteronuclear coupling constants can be directly extracted from COSY-type antiphase peak patterns. The current approach utilizes CPMG-sequences for polarization transfer, and thus avoids the evolution of homonuclear J(HH) couplings, which normally may introduce abnormalities into the cross peak pattern. The differences between LR-CAHSQC and normal LR-HSQC are discussed. (C) 2003 Elsevier Inc. All rights reserved.