23Na MAS NMR spectra

Figure 10 shows the 23Na MAS NMR spectra of some sodium salt ethylene ionomers at room temperature. A broad peak at about —10 to 12 ppm is clearly observed for all samples. The 23Na NMR spectra of the styrene ionomers have been reported44 (details are given in the next section, see Fig. 14). Peaks are observed at about 7, 0, and -12 to -23 ppm, which are assigned to isolated ion pairs, hydrated ions and aggregated ions respectively. The sodium cations in ethylene ionomers, therefore, are almost in ionic aggregates. The isolated ion pairs...

Fig. 10. 23Na MAS NMR spectra of sodium salt of ethylene ionomers (E-0.054MAA-Na and E-0.112MAA-Na) with degrees of neutralization of 20, 60 and 90% at room temperature.

Fig. 11. 23Na MAS NMR spectra of the sodium salt of ethylene ionomer with a degree of neutralization of 0.9 (E-0.054MAA-0.9Na) at various temperatures.

N MAS-NMR spectra, with 23Na-15N and 27A1-15N TRAPDOR and - N CP/MAS-NMR experiments, gave details on NH3 binding sites on 3A zeolite molecular sieves, and dynamics between two primary adsorbed NH3 environments.653 2H and 13C solid-state MAS-NMR data were used to follow the dynamics of deuteriated p-nitroaniline molecules in zeolite ZSM-5 pores.654,655 ll and 13C CP/MAS-NMR spectra were able to probe host-guest interactions between Me3N+(CH2)nN+Me3 (where n = 3 = 10) and zeolites.656... 

Fig. 15. Comparison between the static, MAS and MQMAS 23Na NMR spectra of multisite sodium salts. Contour levels in the 2D plots were taken at 70%, 35%, 16%, 8%, and 4% of the maximum spectral intensities asterisks indicate the spinning sidebands. (Reproduced, with permission, from Medek et a/.209)...

Magic angle spinnine (MAS) at ca. 3.5 kHz was used for 2 Si- and C-NMR measurements, while 23Na-NMR spectra were taken without MAS. For 2 A1- and Li-NMR both techniques were used. The following parameters were used for cross-polarization 13C-NMR (50.3 MHz) and H (200.0 MHz) rf fields were... 

MAS has been applied to a highly viscous cubic phase of a lyotropic LC formed by 1-monooleolyl-rac-glycerol and water in order to obtain liquid-like and 13C spectra.330 Deuterium, sodium, and fluorine NMR spectroscopy have been applied to study the phase behaviour of several dilute lamellar systems formed by low concentrations of an ra-hexadecylpyridinium salt, a sodium salt (e.g., NaBr, NaCl, or sodium trifluoroacetate), 1-hexanol, and D20.331 The 2H, 19F, and 23Na splittings were used to monitor the phase equilibria. The last two studies are motivated by the search of new lyotropic LC for the alignment of biomolecules. 

---