Coupling constants proton-phosphorus

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. 

Gordon, M., Griffin, C. E. Solvent Dependence of Geminal Phosphorus-Proton Coupling Constants in Benzylphosphonium Salts. J. Chem. Phys. 41, 2570 (1964). 

At room temperature, the complexes are extremely fluxional and in fact the proton spectrum shows a doublet (due to coupling with Rh, spin 1/2) of triplets due to the averaged coupling constants of the two phosphorus nuclei. The details of chemical shifts and coupling constants are now well known and can be used for the determination of the solution structures [14]. 

Typical one-bond phosphorus-proton coupling constants... 

Organophosphorus compounds rarely have more than one P atom in the molecule, giving rise to a doublet for any C atom within three bonds (assuming the proton-carbon coupling has been removed) and so these compounds show clearly the connectivity of carbon atoms close to the P atom. The size of the coupling constant is dependent on the number of bonds and the phosphorus oxidation state, such that Vis the largest at about 45-150 Hz, while V and V are of the order of 10-15 Hz. 

The 31P nucleus has a natural abundance of 100% and a spin number of 1/2 (therefore no electrical quadrupole moment). The multiplicity rules for proton-phosphorus splitting are the same as those for proton-proton splitting. The coupling constants are large (/H—p 200-700Hz, and /Hc p is 0.5-20 Hz) (Appendix F) and are observable through at least four bonds. The 31P nucleus can be observed at the appropriate frequency and magnetic field (Chapter 6). 

A detailed, simultaneous analysis (35) of the proton-decoupled 13C NMR spectrum and of the 13C satellites in the proton-decoupled 31P spectrum has allowed all the 31P-31P and 13C -31P coupling constants in 1,6-diphosphatriptycene to be evaluated (Table III). The large C(2)-P(l) coupling and small C(l)-P(6) coupling are considered to be strongly dependent on the orientation of the phosphorus lone-pair electrons and... 

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