Viva la Resolución! Enhancing the Resolution of ¹H NMR Spectra by Broadband Homonuclear Decoupling

Abstract

The structural characterization of synthetic organic and natural products often relies on proton-detected NMR spectra. While the sensitivity of protons is the highest of all NMR-active nuclei, their spectral resolution is rather poor. The removal of scalar couplings leads to a large resolution enhancement by collapsing all signals to singlets. Such homonuclear broadband decoupled proton spectra, which resemble proton-decoupled ¹³C NMR spectra, can be obtained by several techniques, most of which require the acquisition of an additional dimension and/or special data processing. Recently introduced homonuclear decoupling during acquisition yields free induction decays (FIDs), which can be processed and analyzed like regular proton data. This approach can also be implemented in the proton dimension of any two- and multidimensional NMR spectroscopic experiment and is particularly useful when significant signal overlap renders the assignment of scalar-coupled signals impossible.

1 Introduction

2 Direct Homonuclear Broadband Decoupling

3 Experimental Considerations of Slice-Selective Decoupling

Key words

slice-selective decoupling - structure analysis - pure-shift NMR spectroscopy - homonuclear decoupling - two-dimensional NMR spectroscopy

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