Selenium dichloride

Selenium dichloride, SeCl2, is only stable in the gas phase. 

Also reported as commercial products are selenium amino acid chelate, selenium ascorbate, selenium aspartate, and selenium citrate triturations, as well as selenium dibromide, selenium dichloride, selenium lysinate, and selenium sulfide bentonite. 

The method described here is a modification of that of Schoeller.1 Diphenyl selenide has also been prepared from diazotized aniline and alkali monoselenides 2 by the Friedel-Crafts reaction with benzene and selenium tetrachloride3 or selenium dioxide 4 from diphenyl sulfone and selenium 5 from phenylmagnesium bromide and selenium,6 selenium dichloride,7... 

Selenium-containing donors, synthesis and manufacture of, 22 212 Selenium dichloride, 22 75t Selenium diethyldithiocarbamate, 22 73t Selenium dioxide, 22 73t, 75t, 88 toxicify of, 22 95 Selenium disulfide, 22 73t Selenium hexafluoride, 22 75t, 87 toxicify of, 22 96 Selenium hypofluorite, 22 75t Selenium iodides, 22 87 Selenium monobromide, 22 75t, 88 Selenium monochloride, 22 75t, 87 in selenium recovery, 22 85 Selenium monoxide, 22 88 Selenium oxidation, selenium recovery via, 22 81-83... 

There are several different compounds of selenium and the halogen chlorine that range from selenium dichloride (SeCy to selenium oxychloride (SeOCl ), which are used as solvents. 

Sulfur and selenium dichlorides coordinate through the chalcogen atom to form complexes of the type [PdCl2(ECl2)2] (E = S, Se) and these have a trans square planar structure.15 Sulfur... 

Dimethyl selenium dichloride, (CH3)2SeCl2.—A concentrated aqueous solution of the corresponding dinitrate, when treated with hydrochloric acid, gives a precipitate of the dichloride, which is soluble in excess of the precipitant. Crystallisation from alcohol yields white, pearly plates, M.pt. 59-5° C., decomposing at about 70° C. The product has an unpleasant smell, is readily soluble in alcohol, sparingly soluble in water or ether.1... 

Diphenyl selenium dichloride, (C6H5)aSeCl2, is formed when diphenyl selenoxide is treated with hydrochloric acid. It crystallises in glistening prisms, M.pt. 179° to 180° C.4 A similar product is obtained when diphenyl selenide is dissolved in an excess of concentrated nitric acid and concentrated hydrochloric acid added.5... 

Diphenyl selenoxide, (C6H5)2SeO.—This oxide may be prepared in several ways (1) Diphenyl selenium dichloride is treated with sodium hydroxide.6 (2) Diphenyl selenium dibromide is allowed to react with sodium hydroxide.7 (3) 7 grams of diphenyl selenide are slowly treated with 10 c.c. of 46 perhydrol. 8 (4) Diphenyl selenoxide... 

Di-o-tolyl selenium dichloride, (C7H7)2SeCl2,2 is a white product, M.pt. 152°-to 153° C. with decomposition, formed from the corresponding oxide by the action of concentrated hydrochloric acid. 

Dibenzyl selenium dichloride,4 (C6H5.CH2)2SeCl2, occurs when an alcoholic solution of the dinitrate is treated with hydrogen chloride, or when benzylseleninic acid is treated with phosphorus pentachloride. It crystallises in colourless needles, M.pt. 134° to 135° C.5... 

Di-a-naphthyl selenium dichloride,1 (C10H7)2SeCl2.—The corresponding selenide is dissolved in ether and dry chlorine passed in, when an amorphous white precipitate separates. Recrystallisation from xylene yields colourless prisms, 3VI.pt. 130° C., insoluble in alcohols, ether, chloroform, benzene, ligroin and carbon disulphide. 

Di-jS-naphthyl selenium dichloride, (C10H7)2SeCl2, separates from carbon disulphide in colourless leaflets, M.pt. 146° C. 

These derivatives fall into two classes, the first containing an unsubstituted nucleus, and the second having alkoxy-groups in the nucleus. The former may be represented by triphenyl selenium chloride, prepared by adding diphenyl selenium dichloride to a suspension of aluminium chloride in dry benzene. This chloride is crystalline, absorbs atmospheric moisture to yield a dihydrate, and decomposes at its melting-point, forming diphenyl selenide and chlorobenzene. Boiling with ethylene dibromide converts it into triphenyl selenium bromide. The hydroxide has not been isolated in the solid state, but salts have been prepared. The alkoxy-derivatives are represented by... 

Treatment of the hydronitrates in aqueous solution with sodium carbonate causes evolution of carbon dioxide. Evaporation to dryness, followed by extraction with alcohol or benzene, then yields oils which are probably the selenoxides. These oils with concentrated hydrochloric acid are converted into white solids, crystallisable from benzene, xylene, alcohol or dry ether. These solids are the dichlorides of the original selenides, and when prepared by this method their melting-points are as follows Phenyl methyl selenium dichloride, M.pt. 122° C. phenyl ethyl selenium dichloride, M.pt. 64° to 65° C. diphenyl selenium dichloride, M.pt. 142° C. 

Synthetic methods toward 1,2,3,5-diselenadiazole rings have been reported <1989JA9276, 1996CHEC-II(4)743, 2004HOU777>. They involve the reaction of tris(trimethylsilyl)amidine 326 with selenium dichloride generated in situ from selenium and selenium tetrachloride (Equation 48). A number of new derivatives have been prepared by this method, in order to explore the structural, magnetic, and conductivity properties of the radicals. 

It was recently found that selenium dichloride can conveniently be prepared by the reaction of elemental selenium and SO2CI2 It is relatively stable in coordinating solvents and can be used as a reagent for synthetic applications. The attempt to prepare TeCb in the analogous manner from elemental tellurium and SO2CI2 resulted in the formation of various chloridoteUurate anions with different counterions. The solvent and the possible presence of a small amount of residual moisture probably determine the identity of the main product in each individual case. 

To a freshly prepared solution of 0.221 g (1 mmol) of SeCI4 in 25 mL of anhyd CH2C12 are added dropwise 2 mmol of the appropriate alkene. The solution turns a clear yellow within a few seconds. Evaporation of the solvent gives an yellow-orange oil. Crystallization of the oil from pentane or cyclohexane generally gives the bis(2-chloro-l-methylpropyl)selenium dichlorides as colorless, air- and moisture-sensitive solids. 

OZ1/VOE] Ozin, G. A., Vander Voet, A., A gas-phase Raman study of the dissociation of selenium tetrachloride and the vibrational spectrum and molecular structure of selenium dichloride, Chem. Commun., (1970), 896-897. Cited on page 169. 

FER/HAA] Fernholt, L., Haaland, A., Seip, R., Kniep, R., Korte, L., The molecular structure of selenium dichloride, SeCl2, determined by gas electron diffraction, Z Naturforsch, B Chem. ScL, 38b, (1983), 1072-173. Cited on page 169. 

In contrast to sulfur chemistry where dihalides are well established, the isolation of dihalides of selenium and tellurium has only been achieved for SeCl2 and SeBr2 (reactions 15.71 and 15.72). Selenium dichloride is a thermally unstable red oil SeBr2 is a red-brown solid. 

SeCI2[g] SELENIUM DICHLORIDE (GAS) 1471 SIU3 SILICON 3-URANIUM 1520... 

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