Phosphorus absorption bands

Thermopsamine was isolated from Thermopsis lanceolata R. Br. (137). There are two absorption bands of an axial hydroxyl group at 3370 and 1023 cm and bands representative of rrans-quinolizidine at 2680-2800 cm Mn the IR spectrum. Heating of thermopsamine with hydrogen iodide over red phosphorus... 

Scheme 13).16 The presence of the BMes2 group induces a moderate downfield shift of the 31P NMR signal (by 2-3 ppm), suggesting only weak, if any, electron transfer from phosphorus to boron. Consistently, the UV-vis absorption band for 16a (/lmax 332 nm) is blue shifted compared with that of the related NB system (354 nm). 

The X-ray K absorption spectra of phosphorous acid and the phosphites of Na, Al, Mn, Fe", Fe , Ca, Ni and Cd were nearly the same, the head of the absorption band lying at A =5754-1 X-ray units. The band of silver diethyl phosphite was at 5760-4. The values for phosphorus in the elementary state and in different forms of combination were as follows —... 

The phosphorus K shell photoabsorption spectra (XANES and EXAFS) of P406 and P4O10 have been reported in comparison with those of P(OPh)3 and 0=P(0Ph)3 (82,134,135). The absorption bands and their assignments are listed in Table XVI, and the full spectra are depicted in Figs. 11 and 12. 

Nucleic acid also was found in association with the tuberculin protein. Spiegel-Adolf and Seibert investigated the problem spectrographically, and found that the tuberculin protein ( P.P.D. ) precipitated by trichloroacetic acid exhibited an absorption band at 2650-2670 A. This band was identical with that displayed by deoxyribonucleic acid. Precipitation of the tuberculin protein by ammonium sulfate afforded a product which did not display an absorption band in the ultraviolet region of the spectrum. The substance had a lower phosphorus content than that of products obtained by trichloroacetic acid precipitation. The biological activity was not impaired in any way. 

The desulphurization of benzylic sulphides by irradiating them in the presence of tervalent phosphorus compounds has again been used in the synthesis of paracyclophanes. A particularly elegant use of this reaction was made in the synthesis of (71), a compound which exhibits an intramolecular charge-transfer absorption band. There have been several reports of the synthesis of... 

Figure 8 shows absorption spectra of the bis(acetylacetonato) complexes of ethylenediamine (en, N-C-C-N) (12), N-C-C-P, and P-C-C-P in ethanol. The band around 20,000 cm l of each complex can be assigned to the first d-d absorption band, although the intensities increase remarkably with an increase in the number of the ligating phosphorus atoms. From the shift of the band maxima, it is concluded that phosphorus stands at a higher position than nitrogen in the spectrochemical series. 

Frankel et al. (1987) stored 800 g of soybean seeds at rewetted moistures of 13, 16, and 20% for 19—50 days at 4l°C. Soybeans at 13 and 16% initial moisture reached 4l-48°C while the 20% moisture soybeans reached 47-49°C. They found free fatty acids (FFA) climbed from 0.20% to about 1.25% for the 13% moisture soybeans in 49 days. For the 16% moisture soybeans, FFA elevated from 0.5% to about 2.0% in about 27 days. For the 20% moisture soybeans, FFA went from 0.6 to 2.3% in about 28 days. Phosphorus in crude oil before degumming from the 13% moisture-stored soybeans dropped from 1044 ppm to about 400 ppm during the 50-day period. For the 16% moisture beans, it dropped faster from 850 ppm to 0 in 27 days and for the 20% moisture beans, it dropped from 500 ppm to 0 in about 20 days. The reduction in phosphorus was explained by formation of nonhydratable phosphatides, which are made up of Ca and Mg salts of phosphatides (Frankel et al., 1987). They also scanned samples from 1100-2500 nm by using a computerized spectrophotometer, and when second derivatives were taken, they found absorption bands at 2260 nm (R = 0.86) and 1810 nm (R = —0.72) that were correlated to FFA. 

Sulfur, phosphorus, and silicon compounds. Some absorption bands of the heteroatoms S, P, and Si commonly seen in organic compounds are listed in Tables 4.15-4.17. There are many classes of compounds containing S, P, and Si atoms detailed discussions of these compounds may be found in the texts aheady recommended. 

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