Diffusion Coefficients from (13)C PGSE NMR Measurements-Fluorine-Free Ionic Liquids with the DCTA(-) Anion

J Phys Chem Lett. 2012 Feb 2;3(3):441-4. doi: 10.1021/jz201700n. Epub 2012 Jan 23.

Abstract

Pulsed-field gradient spin-echo (PGSE) NMR is a widely used method for the determination of molecular and ionic self-diffusion coefficients. The analysis has thus far been limited largely to (1)H, (7)Li, (19)F, and (31)P nuclei. This limitation handicaps the analysis of materials without these nuclei or for which these nuclei are insufficient for complete characterization. This is demonstrated with a class of ionic liquids (or ILs) based on the nonfluorinated anion 4,5-dicarbonitrile-1,2,3-triazole (DCTA(-)). It is demonstrated here that (13)C-PGSE NMR can be used to both verify the diffusion coefficients obtained from other nuclei, as well as characterize materials that lack commonly scrutinized nuclei - all without the need for specialized NMR methods.

Keywords: DCTA; PGSE; diffusion coefficient; ionic liquid; pulsed-field gradient spin−echo.