28 November 2020

NMR Parameters of Imidazolium Ionic Liquids as Indicators of Their State and Properties in Aqueous Solutions

Seven 1-methylimidazolium-based ionic liquids (ILs) and their aqueous solutions were systematically investigated in order to explore how the NMR spectroscopic properties (chemical shifts, spin–spin coupling constants) are connected or correlated with several physical and chemical properties (density, viscosity, water content, etc.) of ILs and their aqueous mixtures. 1H and 13C NMR chemical shifts of ILs vary markedly depending on different anions, alkyl chain length, and water content. Addition of water affected the NMR parameters in various manners, altering several of them significantly, while others did not change distinctly. Dissimilar behavior of NMR parameters in various solvents at various concentrations allows one to conclude that they reflect several contributions from different properties of ILs and can be used for deep structural investigations.

Reference: ACS Sustainable Chem. Eng. 2021, ASAP

DOI: 10.1021/acssuschemeng.0c09229

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