Sodium chemical shift

Table 15. Sodium-23 Chemical Shifts for the Cryptated Sodium Cation and for the Sodium Anion...

A number of analytical methods have been developed for the determination of chlorotoluene mixtures by gas chromatography. These are used for determinations in environments such as air near industry (62) and soil (63). Liquid crystal stationary columns are more effective in separating m- and chlorotoluene than conventional columns (64). Prepacked columns are commercially available. ZeoHtes have been examined extensively as a means to separate chlorotoluene mixtures (see Molecularsieves). For example, a Y-type 2eohte containing sodium and copper has been used to separate y -chlorotoluene from its isomers by selective absorption (65). The presence of ben2ylic impurities in chlorotoluenes is determined by standard methods for hydroly2able chlorine. Proton (66) and carbon-13 chemical shifts, characteristic in absorption bands, and principal mass spectral peaks are available along with sources of reference spectra (67). 

Chemical shift values were referenced to external sodium 3-trimethylsilyl [2,2,3, 3- H4] propionate... 

Spectroscopic Analysis. Infrared (IR) spectroscopic analysis was performed on a Beckman Microlab 620 MX computing spectrometer. Samples were cast on a sodium chloride pellet or made into a pellet with potassium bromide. and 13C NMR spectra were obtained using a JEOL HNM-FX 270 MHz Fourier transform NMR spectrometer. Samples were dissolved in deuterium chloroform and chemical shifts were referenced to an internal standard of tetramethylsilane. 

Treatment of all four diasteromers of 72 with sodium or potassium bases yielded stilbenes with high stereoselectivity (Scheme 15) <2003T255>. Two of the diastereomers gave rise to some retro-aldol products. In two cases, hexacoordinate species were identified by the upheld 31P chemical shift (5—112 ppm). It was noted that phosphoranes that ring-closed to form hexacoordinate tricyclic species were the ones that did not undergo the retro-aldol reaction to produce aldehydes. The ring closure was disfavored for intermediates with steric repulsion between trifluoromethyl and phenyl groups. 

Fig. 3 Solid state 31P NMR spectra of fosinopril sodium acquired under single pulse, high-power proton decoupling and various conditions of magic-angle spinning (A) static, (B) 2.5 kHz, (C) 4.0 kHz, (D) 5.0 kHz, and (E) 6.0 kHz. The isotropic chemical shift is designated by an asterisk. (From Ref. 15.)...

Fig. 27.—C-l Portions of, 3C-N.m.r. Spectra of Agar (A 24 from Ahneltia plicata), K-Carrageenan (B 25, R = S03 Na+ from Eucheuma striatum), Partially Desulfated k-Carrageenan (C 25, R = S03 Na+ or H), and t-Carrageenan (D 26, R = R = S03 Na+ from Eucheuma spinosum). (Samples were examined as sodium salts in DzO at 90° chemical shifts, 8C, are values relative to external tetramethylsilane.)...

The major absorption in the 31P n.m.r. spectrum of an equimolar solution of penta-phenoxyphosphorane and sodium phenoxide in DMF-acetonitrile is due to the hexaphenoxyphosphate anion, as predicted from the low equilibrium constant estimated for equation (2) (page 35).27 Catechol and phosphorus oxychloride in refluxing benzene gave the spirophosphorane(108), which with triethylamine gave the salt (109).45 On the basis of its 31P chemical shift in DMF solution, (108) was formulated86 as the free six-co-ordinate acid (110), but it seems probable that DMF is... 

A solution-state and solid-state nuclear magnetic resonance study of the complex and its separate components in both their neutral and ionized (TMP hydrochloride and SMZ sodium salt) forms was undertaken in order to elucidate the TMP-SMZ interactions. Inspection of the data for the complex in the solid state shows that the 13C chemical shifts are consistent with the ionic structure proposed by Nakai and coworkers105 (14). Stabilization of the complex is achieved by the resulting ionic interaction and by the formation of two intermolecular hydrogen bonds. 

Obviously, all this refers to observations on liquid samples some work is nevertheless done on solid samples. With great care, one may obtain additional data using solid samples, especially chemical shift anisotropy. Such work has very recently been performed on anhydrous sodium and potassium pyrophosphates, for which crM—crx was measured as 200 + 10... 

For quantitative estimation, a sealed reusable capillary tube, with a known quantity of sodium salt of trimethylsilyl propionic acid (TSP) dissolved in 35 pi of D20, is inserted into the NMR tube while obtaining NMR spectra. The internal standard TSP is used as a chemical shift reference as well as a quantitative standard for the estimation of metabolites, and D20 is used as the field-frequency-lock . Spectra are acquired at room temperature. Typical spectra acquired at room temperature of human bile and standard glycine- and taurine-conjugated BAs are shown in Fig. 5.4.16. 

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