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

Abstract

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 1H– 13C 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.