Phosphorus: coupling constants spectroscopy

The section on Spectroscopy has been expanded to include ultraviolet-visible spectroscopy, fluorescence, Raman spectroscopy, and mass spectroscopy. Retained sections have been thoroughly revised in particular, the tables on electronic emission and atomic absorption spectroscopy, nuclear magnetic resonance, and infrared spectroscopy. Detection limits are listed for the elements when using flame emission, flame atomic absorption, electrothermal atomic absorption, argon ICP, and flame atomic fluorescence. Nuclear magnetic resonance embraces tables for the nuclear properties of the elements, proton chemical shifts and coupling constants, and similar material for carbon-13, boron-11, nitrogen-15, fluorine-19, silicon-29, and phosphorus-31. 

Phosphorus has only one stable isotope, J P, and accordingly (p. 17) its atomic weight is known with extreme accuracy, 30.973 762(4). Sixteen radioactive isotopes are known, of which P is by far the most important il is made on the multikilogram scale by the neutron irradiation of S(n,p) or P(n,y) in a nuclear reactor, and is a pure -emitter of half life 14.26 days, 1.7()9MeV, rntan 0.69MeV. It finds extensive use in tracer and mechanistic studies. The stable isotope has a nuclear spin quantum number of and this is much used in nmr spectroscopy. Chemical shifts and coupling constants can both be used diagnostically to determine structural information. 

Phosphorus NMR spectroscopy serves as a valuable diagnostic tool in the characterization and structural elucidation of primary phosphine compounds. As shown in Table 1, RPH groups resonate in the -125 ppm to -150 ppm range with direct one bond P- H coupling constants of 193-197 Hz. 

In the absence of X-ray crystallographic data, 31P and 195Pt NMR spectroscopy is a useful method to investigate the nature of the products in the solution. In addition to earlier references to these topics, the Pople-Santry theory has been used to calculate the signs and relative magnitudes of the coupling constants for the type of phosphorus-bridged complexes covered in this section.1502... 

Azo dyestuffs derived from sulphonated 1- and 2-naphthols have been studied by means of l3C NMR spectroscopy.95 100 In azo dyes containing fluorine and phosphorus and in 15N-labelled compounds the appropriate y(X,13C) coupling constants have been found. Typical values of these constants are shown in Tables 7, 10, 11 and 14. 

Phosphorus-31 NMR spectroscopy has played a central role in the development of organo-phosphorus chemistry, the chemical shifts being dependent on valency, coordination, bond angles and directly bound atoms, and the coupling constants being used to identify adjacent NMR active nuclei and indicate stereochemistry [Pg.865]

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