A new NMR approach is proposed for the measurement of long-range heteronuclear coupling constants (nJXH, n > 1) in natural abundance molecules. Two complementary in-phase (IP) and anti-phase (AP) data are separately recorded from a modified HSQMBC experiment and then added/subtracted to provide spin-state-selective α/β-HSQMBC spectra. The magnitude of nJXH can be directly determined by simple analysis of the relative displacement between α- and β-cross-peaks. The robustness of this IPAP-HSQMBC experiment is evaluated experimentally and by simulation using a variety of different conditions. Important aspects such as signal intensity dependence and presence of unwanted cross-talk effects are discussed and examples on the measurement of small proton-carbon ( nJCH) and proton-nitrogen (nJNH) coupling constants are provided. © 2010 Elsevier Inc. All rights reserved.
|Journal||Journal of Magnetic Resonance|
|Publication status||Published - 1 Dec 2010|
- Long-range proton-carbon coupling constants