Multiplicity Editing by 2D E-HSQC NMR Spectroscopy: A Product Operator Theory Study

Abstract

Multiplicity editing of NMR signals into subsignals has become a useful technique to obtain simplified spectra for the separation of carbonyl groups in complex molecules. An E-HSQC experiment is an 1H-detected, signal-edited and two-dimensional (2D) heteronuclear single quantum coherence (HSQC) NMR spectroscopy experiment. The product operator theory as a quantum mechanical method not only allows the confirmation of experimental results but also offers to make experimental suggestions on NMR experiments. In this study, analytical descriptions of the 2D E-HSQC NMR experiment for two different editing pulse blocks have been presented for a weakly coupled IS<inf>n</inf> (I=1/2; S =1/2, 1; n=1, 2, 3) spin system by using the product operator theory. According to the obtained free induction decay (FID) values, theoretical predictions and experimental conditions have been suggested for spectral editing of 13C/15NH, 13C/15NH<inf>2</inf>, 13C/15NH<inf>3</inf> and 13C/15ND, 13C/15ND<inf>2</inf>, 13C/15ND <inf>3</inf> signals into subsignals. © 2009 The Royal Swedish Academy of Sciences.