Selenium bis

Selenium, bis(diethyldithiocarbamato)-stereochemistry, 60 Selenium, bis(dithiofurancarbamato)-stereochemistry, 60 Selenium(II) complexes bis(dithiochelate), 60 Selenocyanate complexes linkage isomers, 186 Selenonium ions, trifluoro-stereochemistry, 37 Self-exchange reactions, 333 electron transfer rate constants, 347-353, 366 rate constants calculation, 348 rate constants, 362 Semicarbazide, 1,4-diphenylthio-ruthenium determination, 546 Semi-glycinecresol red metallochromic indicator, 557 Semi-xylenol orange metallochromic indicator, 557 Seven-coordinate compounds stereochemistry, 69-83 Sidgwick, Nevil Vincent, 16 Silicon, tris(acetylacetone)-configuration, 195... 

Alcoholysis of the acyl organyl sulfides RC(0)SxR (R, R =alkyl, aryl x=2, 3) in the presence of hydrogen chloride gives the organyl hydrodi- and hydrotrisulfides RSxH (x=2,3) in good yield [20,21,65,176,282]. Acyl alkyl disulfides react with thiols to yield asymmetrical disulfides [200]. Selenium bis(thiocar-... 

Insertion reactions of selenium- and sulfurdiimides are also pronounced. Selenium bis(t-butylimide) reacts with triethylborane to give a four-membered ring insertion product 6559. 

Furalazine, Acetylfuratrizine, Panfuran-S. Heating nitrovin in butanol or dimethylformamide at 100—130°C affords furalazine, 6-[2-(5-nitro-2-furanyl)ethenyl]-l,2,4-triazine-3-amine (34). An improved synthesis originates with 5-nitro-2-furancarboxaldehyde and acetone, proceeds through 4-(5-nitro-2-furanyl)-3-buten-2-one followed by a selenium dioxide oxidation to the pymvaldehyde hydrate, and subsequent reaction with aininoguariidine (35). Furalazine, acetylfuratrizine (36), and the A[-A/-bis(hydroxymethyl) derivative, Panfuran-S, formed from the parent compound and formaldehyde (37), are systemic antibacterial agents. 

The chalcogene heterocycles have been used as stable precursors for sulfur-said selenium-cantaining hetero-l,3-dienes in cycloaddition reactions 3//-l,2,4-Thiaselenazoles are a convenient source of 4,4-bis(trifluoromethyl)-l-thia-3-aza-buta-1,3-dienes, and 3//-diselenazoles are a convenient source of 4,4-bis(trifluoromethyl)-l-selena-3-azabuta-l,3-dienes as well as bis(tnfluoro-methyl)-substrtuted nitrile ylides [137]... 

A redox process also occurs in the reaction of selenium diimides with bis(amino)stannylenes. Eor example, the cyclic stannylene McaSi)//-N Bu)2Su reacts in a 1 1 molar ratio with BuN=Sc=N Bu to give a spirocyclic tin complex, which reacts with a second equivalent of the stannylene to generate a Sn-Sn bond [d(Sn-Sn) = 2.85 A, /( Sn- Sn) = 13,865 Hz)] (Scheme 10.6). ... 

Scheme 10.6 Reaction of a selenium diimide with a bis(amino)stannylene...

Dimethylquinoxaline reacts with pyridine and iodine to form quinoxaline-2,3-bis(methylenepyridinium iodide) (55). Condensation of (55) with p-nitrosodimethylaniline in the presence of potassium carbonate yields the bis-(p-dimethylaminonitrone) (56) and this on acid hydrolysis gives quinoxaline 2,3-dialdehyde (57) in high over-all yield. The dialdehyde is also obtained by selenium dioxide oxidation of 2,3-dimethylquinoxaline. ... 

The molar ratio of the III compound to the V compound is typically l/lO.t ] To obtain the desired semiconductor properties, dopants are added such as zinc (from diethyl zinc) or magnesium (from bis(cyclopentadienyl) magnesium) for p doping, and silicon (from silane) or selenium (from hydrogen selenide) for n doping. 

The first product of dicoordination, 18, was synthesized via treatment of phos-phinoiminophosphanes with selenium. The latter then inserted into the PP-bond and formed finally a bis-coordinated donor-acceptor complex [55]. The overall synthetic route is shown in Scheme 10. 

The absorption of the ether bis(2-fluoroethoxy)methane from the soil and its translocation in plants in a concentration sufficient to kill insects is a recent discovery heretofore observed only in some selenium compounds and in the insecticidal esters of some polyphosphoric acids (4) Whether this property is shared by other organofluorine compounds will doubtless be determined for the purpose of studying plant metabolism and of evaluating any practical application. 

Oxidation of 2,3-dimethylquinoxaline (from phenylenediamine and diacetyl) with either peracids or hydrogen peroxide in acetic acid gives the 1,4-dioxide (162). Treatment of this bis-N-oxide with selenium dioxide leads to oxidation of one of the methyl groups to the methyl carbinol and formation of... 

The first examples of mononuclear disulfur and diselenium complexes of platinum have been described.330 Reduction of the sterically hindered complex trans- PtC 2( P M e2A r)2] (Ar = 2,4, 6-tris[bis(trimethylsilyl)methyl]phenyl, 2,6-bis[bis(trimethylsilyl)-methyl]-4-[tris(trimethylsilyl) methyl]-phenyl) with lithium naphthalide in THF solution affords the platinum(0) species [Pt(PMe2Ar)2]. Oxidative addition of elemental sulfur or selenium yields the dichalcogenatoplatinum(II) complexes of the type [PtE2(PMe2Ar)2] (E = S, Se) containing a unique PtE2 ring system. The complexes are stable to air in the solid state, but slowly decompose in solution after several days at room temperature. 

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