Study And Application Of NMR Spectra Of Phosphorus-containing Compounds

As an important kind of chemical materials, phosphorus-containing compounds are widely used in detergents, pesticides, pharmaceuticals, water treatment agents, and so on. The detection method of 31P NMR is of rapidity, accuracy, high resolution, and 31P NMR can rapidly detect what phosphorus-containing compounds are in samples. There is an urgent need that NMR spectra database of phosphorus-containing compounds is to be established as the basis and guidance for the detection method of 31P NMR.In this paper, NMR spectra data of phosphorus-containing compounds was established, and the changing regularity of chemical shifts and coupling constants of various phosphorus-containing compounds was studied systematically. Then the NMR spectra was used to detect 30 samples submitted for test by enterprises, as well as several kinds of detergents purchased randomly in the market. The main research contents and results were summarized as follows:115 phosphorus-containing compounds including 31 inorganic compounds and 84 organic compounds were collected in this research. Then 31P NMR of inorganic compounds and 31P NMR,1H NMR,13C NMR of organic compounds were tested by NMR Spectrometer. Phosphorus-containing compounds were classified according to the existing form of phosphorus atoms in the compounds.The changing regularity of chemical shifts of phosphorus-containing compounds shows that substitution with an electronegative functional group usually results in a downfield chemical shift for the phosphorus atom in inorganic compounds, and a downfield chemical shift will be caused as the metallic radius increases. When the coordination number increases from 2 to 6,31PNMR chemical shifts move from downfield to highfield. The relationship of chemical shift and structures of organic phosphorus-containing compounds in 31P NMR, including electronegative functional group, the coordination number, the type of heteroatom attaching to phosphorus, bond angle, was reviewed. Generally, substituting hydrogen for the more electronegative functional groups in the phosphorus-containing compounds leads to the expected downfield shift, and phenyl substituents cause an upfield shift compared to respective alkylated phosphorus-containing compounds. The relationship between coordination number of phosphorus and 31P chemical shift in organic phosphorus-containing compounds is similar with that in inorganic phosphorus-containing compounds. With the electronegativity of heteroatom (such as sulfur, oxygen and nitrogen attaching directly to phosphorus) increasing,31P chemical shift moves to downfield. It also means that increasing the atomic radius of heteroatom causes a downfield shift.31P chemical shift moves to downfield as the bond angle of nontetracoordinated phosphorus-containing compounds increases. The bond angle effect on chemical shifts in tetracoordinated phosphorus-containing compounds is contrary to that in nontetracoordinated phosphorus-containing compounds. The changing regularity of coupling constants is summerized as follows:As with other nuclei, nJPH coupling constants have a tendency to decrease when the value of n increases, though exceptions are known. Although 1JPH values are frequently in the range of 400-1000Hz, the coupling constants drop rapidly. The coupling of phosphorus to carbon follows the general trends observed with other nuclei. The magnitude of nJPH is dependent on the oxidation state and the coordination number of phosphorus, the value of n and the stereochemical disposition of coupling nuclei.To determine phosphorus-containing compounds of the 30 samples submitted for test by enterprises, the spectra and data obtained from test should be referred to the standard NMR spectra database of phosphorus-containing compounds. Other ingredients were measured by NMR technology in combination with the analysis methods of X-ray, ICP-MS, IR, etc. The structures of phosphorus-containing compounds in marketing detergents were identified by comparing the 31P NMR technology. Establishing NMR spectra data of phosphorus-containing compounds not only plays an important role in studying phosphorus-containing compounds, but also can save a great deal of time, humanforce, materials and other resources. Therefore, this research is feasible and actual significant.