Optimization of Diffusion-Filtered NMR Experiments for Selective Suppression of Residual Nondeuterated Solvent and Water Signals from ¹H NMR Spectra of Organic Compounds

Interpretation of ¹H NMR spectra of organic compounds is sometimes hampered by the presence of strong peaks arising from residual nondeuterated solvent and water that obscure compound signals. Classical solvent suppression techniques such as presaturation or those based on pulsed field gradients are not effective in this regard because they also remove the compound resonances that overlap with the solvent signal being suppressed. Here, we propose an alternative scheme by using an optimized NMR diffusion filter that eliminates the nondesired peaks while retaining the signals of interest. This strategy has proved to be useful in three common deuterated solvents, namely, CDCl₃, DMSO-d₆, and CD₃OD, resulting in clean spectra with no interference from solvent or water peaks.