31P chemical shift

Fig. 8.10 31P chemical shift anisotropy (CSA) tensor orientation of a nucleotide from a DNA dode-camer with its helix axis pointing vertically. The DNA structure has been calculated using CSA data obtained under anisotropic conditions 

TABLE 2. 31P NMR chemical shifts (ppm) of phosphonium and aminophosphonium halides35,37 (also steric compression was shown to give upfield 31P chemical shifts in cycloalkyltriphenylphosphonium salts) 

Thus, DFT-IGLO calculations of the 31P chemical shift without spin-orbital corrections yielded a value of S = 274, whereas additional spin- 

An excellent example of the use of 31P chemical shifts, in combination with H-NMR and 103Rh-NMR data as well as coupling constants information, can be found in the report by Duckett et al. [21] on the activation of 

The resulting product showed a single 31P chemical shift at 40 ppm with a XJ coupling to rhodium of 118 Hz, indicative of a rhodium (III) center. As this rhodium atom was shown to couple to two phosphorus atoms, it could be concluded that the phosphorus atoms are in a symmetrical position, as shown in Figure 11.3. The other Rh atom couples only to a phosphoms atom with a jphp of 196 Hz, indicative of a rhodium (I) center. 

Proton and Carbon Spectra. Proton and carbon NMR data, including 31P chemical shift and P—C coupling constants for the above compounds are given in Scheme 3.27. 

NMR spectroscopy of phosphaalkenes and other compounds containing C—P double bonds has been reviewed309. Considerable differences in the 31P chemical shifts have been found for diastereomeric pairs of phosphaalkenes, for example310,311  

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