More than ADEQUATE: doubling the sensitivity of 13CH-13CH correlations in double-quantum NMR experiments

Chem Commun (Camb). 2022 Nov 22;58(93):13011-13014. doi: 10.1039/d2cc05214h.

Abstract

We present modifications of the ADEQUATE experiment which more than double the sensitivity of carbon-carbon correlations of 13CH-13CH moieties. Additionally, these improvements can be applied without a sensitivity penalty to obtain spectra with a 13C chemical shift axis in the indirectly detected dimension, instead of a double-quantum frequency, allowing simpler interpretation of spectra. The modified experiments, which use refocussing of 1JCH couplings and 1H decoupling during JCC evolution intervals, were tested on several molecules, including a pentasaccharide (20 mg, 19 mM), where on average a 2.6-fold signal-to-noise improvement was achieved and the number of observable correlations increased. Doubling sensitivity results in a 4-fold reduction of the experimental time, allowing ADEQUATE spectra to be recorded overnight instead of over multiple days.

MeSH terms

  • Carbon*
  • Magnetic Resonance Imaging*
  • Magnetic Resonance Spectroscopy / methods

Substances

  • Carbon