Xenon Dynamics in Ionic Liquids: A Combined NMR and MD Simulation Study

[Image: see text] The translational dynamics of xenon gas dissolved in room-temperature ionic liquids (RTILs) is revealed by (129)Xe NMR and molecular dynamics (MD) simulations. The dynamic behavior of xenon gas loaded in 1-alkyl-3-methylimidazolium chloride, [C(n)C(1)im]Cl (n = 6, 8, 10), and hexafluorophosphate, [C(n)C(1)im][PF(6)] (n = 4, 6, 8, 10) has been determined by measuring the (129)Xe diffusion coefficients and NMR relaxation times. The analysis of the experimental NMR data demonstrates that, in these representative classes of ionic liquids, xenon motion is influenced by the length of the cation alkyl chain and anion type. (129)Xe spin–lattice relaxation times are well described with a monoexponential function, indicating that xenon gas in ILs effectively experiences a single average environment. These experimental results can be rationalized based on the analysis of classical MD trajectories. The mechanism described here can be particularly useful in understanding the separation and adsorption properties of RTILs.