Phosphines selenides

Organ oselenium compounds, such as phosphine selenides, are being evaluated in solvent extraction systems for silver and gold (63). Also, potential pharmaceuticals containing selenium have been prepared (64). 

Electron donors which interact at only one end of the X2 or XY molecule form simple adducts (Fig. 1, mode A), often referred to as a spoke structure. The diiodine complex of tris(diethylamino)phosphine selenide (PAQKIB) [ 135] shown in Fig. 2a is an excellent example of this mode, as the Se- I distance at one end of the I2 molecule is 2.715 A, while at the other end there are no close contacts with any other atom. 

Tertiary phosphine selenides have been prepared either by direct fusion of the tertiary phosphine with elemental selenium1 or by refluxing the phosphine with selenium in an inert solvent.2 In the case of a solid phosphine, such preparations often require numerous and time-consuming extractions to obtain the pure phosphine selenide. 

Although no extensive data are available for evaluating the toxicity of phosphine selenides, these compounds are similar to organophosphates and -thiophosphates, many of which are insecticides and related to the so-called nerve gases. 3 A high toxicity for mammals has been noted in (RO)2P(Se)X compounds 3 Consequently, the phosphine selenides should be handled carefully. 

Oxidative Halogen Addition to Chalcogen-ocarbonyl Functions R2C = Y and to Phosphine Selenides R3P — Se 850... 

Tertiary phosphine sulfides are generally stable compounds and are not easily oxidised by air, although they can be oxidised by hydrogen peroxide or dilute nitric acid. The analogous tertiary phosphine selenides and tellurides are however, more reactive to oxidation. Similar to the sulfides they can be prepared from the direct reaction of elemental chalcogen with a tertiary phosphine (Equation 1). Tertiary phosphine selenides are also accessible from tertiary phosphines using KSeCN as the selenium source instead of the element itself. 

Phosphine selenides are stronger soft donors than the sulfides.55 The solid 1 1 adduct of /Pr3P Sc with I2 is ionic (iPr3PSe)2I+ 13 reaction of... 

Oxidative Halogen Addition to Chalcogenocarbonyl Functions R2C=Y and to Phosphine Selenides R3P=Se... 

Packing of Solid Phosphine Selenide Dibromides RR 2PSeBr 2... 

Bromination of phosphine selenides leads to molecular phosphine selenide dibromides that contain T-shaped P-SeBr2 functions. Structural investigation of a series of closely related trialkylphosphine selenide dibromides RR 2PSeBr2 (R,R =zPr, /Bu) revealed remarkable differences in the packing of these T-shaped compounds.81... 

Tellurium dihalide complexes L2TeX2 (L=ligand) tend to give planar 4-coordi-nated structures.2,3,9 From bidentate phosphine selenides dppmSe2 [Ph2P(=Se)CH2P(=Se)Ph2] and dppeSe2 two different kinds of 1 1 complexes... 

Phosphine complexes, osmium, 19 642 Phosphine coordination complexes, of uranium, 25 436 Phosphine derivatives, 19 28 Phosphine oxide(s), 11 495-496 19 66 predicted deviations from Raoult s law based on hydrogen-bonding interactions, 8 814t in salicylic acid manufacture, 22 8 Phosphine oxide diols/triols, 11 501 Phosphine selenides, 22 90 Phosphinic acid, 19 20, 54-55 Phosphinic anhydride, 11 499 Phosphinothricin acetyltransferase (PAT) proteins, 13 360 Phosphite esters, 19 20 Phosphites, in VDC polymer stabilization, 25 720... 

Reactants HPS = tri(n-butyl)phosphine selenide BPT = tri(n-butyl)phosphine teluride NTA = nitrilotriacetate complex ion SeCN = sellenocy-anide SOS = selenosulfite STS = sodium thiosulfate TeCN = tellurocyanide TEMS = trifluoromethane sulfanate TSS = triphenylstibine sulfide. 

Michalski, J. The chemistry and stereochemistry of organic selenium-phosphorus acids and phosphine selenides. Ann. N.Y. Acad. Sci. 192, 90 (1972). 

A number of metal complexes with bidentate phosphine selenide ligands, e.g. Ph2P(Se)(CH2) -P(Se)Ph2 (k = 1 or 2), have been reported but, unlike the monodentate phosphine selenides, have yet to be successfully characterized by X-ray crystallography. The coordination of selenium in these types of ligands is amenable to examination by inspection of the vPS vibration in the IR spectra.29,30... 

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