<sup>129</sup>Xe NMR in Liquid Crystals: Detection of Induced Smectic Phases in Binary Mixtures of Nematic Liquid Crystals by Use of Xenon Gas as a Probe

Jokisaari, Jukka; Diehl, P.; Muenster, O.

doi:10.1080/00268949008047816

Cited by 12 publications

(6 citation statements)

References 10 publications

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“…Nuclear magnetic resonance (NMR) spectroscopy using 129 Xe is commonly practiced to investigate many different materials such as gases 1 , liquids 2 – 4 , liquid crystals 5 , 6 , and porous solids 7 – 10 . This is because the 129 Xe chemical shift constitutes a sensitive, inert probe of the physical properties of the host material.…”

Section: Introductionmentioning

confidence: 99%

Chemical shift extremum of 129Xe(aq) reveals details of hydrophobic solvation

Peuravaara

Karjalainen

Zhu

et al. 2018

Sci Rep

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The 129Xe chemical shift in an aqueous solution exhibits a non-monotonic temperature dependence, featuring a maximum at 311 K. This is in contrast to most liquids, where the monotonic decrease of the shift follows that of liquid density. In particular, the shift maximum in water occurs at a higher temperature than that of the maximum density. We replicate this behaviour qualitatively via a molecular dynamics simulation and computing the 129Xe chemical shift for snapshots of the simulation trajectory. We also construct a semianalytical model, in which the Xe atom occupies a cavity constituted by a spherical water shell, consisting of an even distribution of solvent molecules. The temperature dependence of the shift is seen to result from a product of the decreasing local water density and an increasing term corresponding to the energetics of the Xe-H2O collisions. The latter moves the chemical shift maximum up in temperature, as compared to the density maximum. In water, the computed temperature of the shift maximum is found to be sensitive to both the details of the binary chemical shift function and the coordination number. This work suggests that, material parameters allowing, the maximum should be exhibited by other liquids, too.

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Section: Introductionmentioning

confidence: 99%

Chemical shift extremum of 129Xe(aq) reveals details of hydrophobic solvation

Peuravaara

Karjalainen

Zhu

et al. 2018

Sci Rep

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“…This is not surprising as the interaction between two precisely side-by-side quadrupoles of opposite sign is attractive, and would be expected to favour the formation of layers. It is interesting to note that a smectic phase has been observed for mixtures of liquid crystals whose components are nematic and for which the solute D 2 experiences ®eld gradients of opposite sign in the components [13]. In addition, because of the favourable interquadrupole interactions, a discotic phase results from simulations of oblate GB ellipsoids which contain quadrupoles of opposite sign [14].…”

Section: Resultsmentioning

confidence: 99%

Monte Carlo simulations of zero electric field gradient liquid crystal mixtures

Burnell

Berardi²,

Syvitski

et al. 2000

Chemical Physics Letters

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“…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.…”

Section: Introductionmentioning

confidence: 99%

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

Vemulapalli

Jagadeesh

2015

Molecular Crystals and Liquid Crystals

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The anisotropic environment of the thermotropic nematic liquid crystal (LC),, is probed by using 129 Xe NMR spectroscopy. The temperature versus 129 Xe nuclear shielding of the xenon gas dissolved in 5CB LC has clearly shown the nematic-isotropic phase transition. The observed linear and non-linear behavior of 129 Xe chemical shifts in the isotropic and nematic phases, respectively, are explained by using the pair-wise additive model. Furthermore, the parameters such as 129 Xe shielding constant (σ 0 ), the anisotropy of the shielding tensor (σ 0 ), the temperature dependence of the isotropic shielding (ε), and the shielding anisotropy (χ ), are derived.

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¹²⁹Xe NMR in Liquid Crystals: Detection of Induced Smectic Phases in Binary Mixtures of Nematic Liquid Crystals by Use of Xenon Gas as a Probe

Cited by 12 publications

References 10 publications

Chemical shift extremum of 129Xe(aq) reveals details of hydrophobic solvation

Chemical shift extremum of 129Xe(aq) reveals details of hydrophobic solvation

Monte Carlo simulations of zero electric field gradient liquid crystal mixtures

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

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129Xe NMR in Liquid Crystals: Detection of Induced Smectic Phases in Binary Mixtures of Nematic Liquid Crystals by Use of Xenon Gas as a Probe

Cited by 12 publications

References 10 publications

Chemical shift extremum of 129Xe(aq) reveals details of hydrophobic solvation

Chemical shift extremum of 129Xe(aq) reveals details of hydrophobic solvation

Monte Carlo simulations of zero electric field gradient liquid crystal mixtures

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

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Product

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¹²⁹Xe NMR in Liquid Crystals: Detection of Induced Smectic Phases in Binary Mixtures of Nematic Liquid Crystals by Use of Xenon Gas as a Probe

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