NMR Determination of the ¹²⁹Xe Shielding Anisotropy for Xenon Gas Dissolved in Liquid Crystals

Nondisruptive Dissolution of Hyperpolarized 129Xe into Viscous Aqueous and Organic Liquid Crystalline Environments

“…Xenon NMR is also useful in material science as a highly sensitive, inert probe for the properties of liquid‐crystal (LC) phases, nanochannels, and porous structures, and as a real‐time reporter for the progress of chemical processes . Anisotropic chemical environments, such as LC phases, can cause substantial shielding anisotropy in the xenon chemical shift tensor . This anisotropy is due to deformation of xenon's electron cloud caused by the ordering of molecules near it.…”

“…By contrast, the dissolution of xenon into stationary liquids has been accomplished in two different ways: first, by pressurization with thermally polarized (TP), isotopically enriched, pure xenon sources, and second, by using porous polypropylene hollow membrane fibers . Until now, the only way to visualize viscous media by 129 Xe NMR spectroscopy was through TP‐xenon pressurization, which is costly and often time consuming compared to hp‐ 129 Xe experiments.…”

129Xe NMR Investigation of the Anisotropic Environment of a Thermotropic Nematic Liquid Crystal 4-Cyano-4′-Pentylbiphenyl

“…1], has offered a unique means of probing the anisotropic environment [7,8]. The important physical properties of xenon gas, for example, (1) mono atomic and small in diameter (∼4Å), which allows the xenon atoms to easily occupy the inter-molecular spaces and (2) sensitive to the physical environment in which the xenon atoms are dissolved, resulting in a wide 129 Xe chemical shift range (∼300 ppm), have led the 129 Xe NMR spectroscopy to probe into the mesophases of thermotropic liquid crystals [9][10][11][12][13][14][15][16][17]. Furthermore the 129 Xe chemical shifts in anisotropic systems carry information about the average molecular ordering and shielding anisotropy that can be analyzed in the framework of mean-field approximation.…”

129Xenon NMR: Review of recent insights into porous materials

“…During the last 35 years, 129 Xe NMR spectroscopy has been applied on various systems, such as porous materials, systems with supported metals [6][7][8][9][10][11], polymers [12][13][14][15][16][17][18], biomolecules [19][20][21][22][23], liquid crystals [24][25][26][27][28] etc. Important theoretical developments have been performed for a better understanding of the NMR chemical shift and line shapes of 129 Xe [28][29][30][31][32][33][34].…”