Application of Diffusion-Ordered Spectroscopy (DOSY) as a Solvent Signal Filter for NMR in Neat Ionic Liquids



The use of common, that is nondeuterated, ionic liquids for NMR spectroscopic purposes as the only solvent causes large signals arising from solvent resonances. Ionic liquids (ILs) with long side chains possess signals throughout the spectral range of protons, thus rendering simple solvent signal suppression techniques ineffective. Here we present solvent signal suppression based on diffusion-ordered NMR spectroscopy (DOSY). In contrast to the well established usage of DOSY to filter water resonances from biological systems, here we filter out the slower moving molecules. This method allows in many cases for the complete removal of the solvent signals from 1H spectra of solutes and may become a useful tool for in situ studies of reactions performed in ILs. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)