Antimony V Salts

Beckmann rearrangement. The antimony(V) salt 1 is an effective catalyst for Beckmann rearrangement of ketoxime trimcthylsilyl ethers to amides or lactams. ... 

The + 5 acid is known in solution and antimonates(V) can be obtained by dissolving antimony(V) oxide in alkalis. These salts contain the hexahydroxoantimonate(V) ion, [Sb(OH)(,] . 

A similar procedure may also be used for the determination of antimony(V), whilst antimony (III) may be determined like arsenic(III) by direct titration with standard iodine solution (Section 10.113), but in the antimony titration it is necessary to include some tartaric acid in the solution this acts as complexing agent and prevents precipitation of antimony as hydroxide or as basic salt in alkaline solution. On the whole, however, the most satisfactory method for determining antimony is by titration with potassium bromate (Section 10.133). 

A brownish-purple solid salt, T SbCls, made by reacting thianthrene with antimony(V) chloride at room temperature in chloroform (62BCJ1137, 62JCS4963 67BCJ2539), was shown, by comparison with a methylene chloride solution of the salt, to have the radical as free in the solid as in solution (69BCJ548). Antimony(V) chloride was used to oxidize a thianthrene-containing polymer, —[T—C(Ph)=C(Ph) presumably... 

In the presence of a catalytic amount of an antunony(V) salt (SbCU SbFe ), generated from antimony(V) chloride and silver hexafluoroantimonate, the Beckmann rearrangement of several ketoxime trimethylsilyl ethers proceeds smoothly to give the corresponding amides or lactams in good yields . ... 

The action of strong aprotic Lewis acids (antimony(V) fluoride, arsenic(V) fluoride etc.) provokes the ionization of xenon difluoride, leading to the formation of fluoroxenonium salts XcF + MFn or Xe2F3 MFn less strong acceptors of the fluoride ion (hydrogen fluoride, boron trifluoride, etc.) polarize the xenon difluoride molecule. 

Arenediazonium hexafluoroantimonates were described as early as 1935,275 but their fluorodediazoniation was only studied much later.276 They deliver fluoroaromatics in better yields than other diazonium salts only when electron-withdrawing groups (N02, C02H) are present on the ring. Otherwise, antimony(V) fluoride formed in the reaction acts as a strong Lewis acid and catalyzes the formation of byproducts. The phenomenon is more pronounced with diazonium hexafluoroarsenates which deliver fluoro compounds in acceptable yields only from nitroanilines.276 With unsubstituted or electron-releasing substituted anilines, difluo-rinated arenearsonic acids are often the major product. 

Antimony(V) Oxide and Derivatives 28.1L3.1 Antimony oxoacids and their salts... 

Antimony(V) sodium tartrate Schistosoma japonicum Less toxic than K salt 257 (mouse intravenous) Schistosomiasis... 

More recently, salts of the triphenylmethyl cation Ph3C+ have been shown to be effective in converting the diones into pyrylium salts (61BSF538). The cation may be generated in situ, for example from triphenylmethyl chloride and antimony(V) chloride (69T1209). The r-butyl cation has been used for the same purpose (67T4001). Earlier workers considered that the synthesis involved dehydration of the diketone to a 4//-pyran followed by rapid oxidation to the pyrylium salt. In view of the successful application of Ph3C, the reaction... 

A simple synthesis of these salts became available with the recognition that oxygen, fluorine, and arsenic or antimony-(V) fluoride, at pressures near atmospheric, react to form the appropriate dioxygenyl salts when exposed to ordinary sunlight Filtered by Pyrex glass.4 Thus, the atmospheric-pressure, photochemical synthesis is the safest and most convenient one to date. 

Carbon functional groups, attachment to polysilanes, 3, 585 Carbon-heteroatom bond formation via antimony(III) compounds, 9, 428 via antimony(V) compounds, 9, 432 via bismuth(III) compounds characteristics, 9, 440 with copper catalysts, 9, 442 non-catalyzed reactions, 9, 443 with bismuth(V) compounds, 9, 450 with bismuthonium salts, 9, 449 with bismuth ylides, 9, 450 Carbon-heteroatom ligands in tetraosmium clusters, 6, 967 in tetraruthenium clusters, 6, 960... 

In 1935, the American Federal Bureau of Investigation pointed out that the test was not specific and had reservations about its use.118 Other evaluations of the technique proved it to be completely unreliable as an indicator of FDR. Common substances such as tobacco, tobacco ash, fertilizers, certain pharmaceuticals, certain paints, and urine also give positive results.119120 In addition a number of oxidizing agents such as chlorates, bromates, iodates, permanganates, chromates, vanadates, molybdates, antimony(V), and ferric salts also give a reaction.121,122 At the Interpol Conference in Paris in 1968 it was officially concluded that the paraffin test should no longer be used.123... 

The arsenic sub-group consists of the ions arsenic(III), arsenic(V), antimony(III), antimony(V), tin(II) and tin(IV). These ions have amphoteric character their oxides form salts both with acids and bases. Thus, arsenic(III) oxide can be dissolved in hydrochloric acid, (6m) and arsenic(III) cations are formed ... 

Two series of salts are known, with antimony(III) and antimony(V) ions in them these are derived from the oxides Sb203 and Sb205. 

The polycondensation of l,l -dicarboxycobalticenium chloride with aromatic diamines in molten antimony trichloride at 150-175 °C gave polyamides containing the cobalticenium tetrachloroantimonate(V) salt system in the repeating unit (Eq. 5)9. ... 

There is no well-defined antimony(V) acid either, nor has an Sb04 ion ever been observed. All known antimonates are based on Sb06 octahedra, and there are three classes. The simplest, obtained by addition of dilute alkali hydroxides to SbCl5, contain the Sb(OH)6 ion. Several alkali metal salts of these are known. Other antimonates that consist of linked Sb06 octahedra are obtained by heating mixed oxides and have formulas such as M Sb03, and MinSb04. The... 

Antimony(lll) fluoride, " antiinony(lll) fluoride activated with pentavalent antimony salts [anlimony(V) fluoride, antimony(V) chloride, antimony(V) bromide, or by the addition of bromine or chlorine to form pentavalent antimony salts in situ], SbFjX, and antimony(V) fluoride substitute active halogens. In general, antimony fluorides can substitute halogens in polyhalogenated compounds when more than one possible site of fluori-natioii is present, the following order of reactivity is observed (where X = Br or C ) ... 

Ethane-1,2-dioyl dichloride oxalyl chloride (COCOj) reacts with antimony(V) fluoride above -35 "C to form COCIF (identified by in situ infrared analysis) and SbFj. The reaction was accompanied by the generation of a small quantity of CO, and possibly COFj. Examination of the infrared spectrum during the progress of the reaction when cooled to -50 C revealed the formation of an intermediate oxocarbonium salt. The reaction was interpreted in the following terms [7] ... 

Not only free cycloprop-2-enecarboxylic acids but also esters 5 were decarbonylated in oxidizing Bronsted acids, such as 25% sulfur trioxide in sulfuric acid, chlorosulfonic acid or fluorosulfuric acid, with evolution of carbon monoxide. Nearly quantitative formation of the corresponding cyclopropenylium ions 6 in solution was demonstrated by HNMR spectroscopy, and the hexachloroantimonate salts 7 were isolated when the solutions were treated with antimony(V) chloride in aeetyl chloride. ... 

The reaction of dicarboxylic acid dichlorides with aryl cyanides in the presence of antimony(V) chloride gives his(1,3,5-oxadiazinium) salts 9a-l whose colors range from yellow to brown.67 The stability of the salts increases with the distance of the heterocyclic rings from each other. 

Methyl thiocyanate reacts with thioaroyl chlorides and antimony(V) chloride to give the 2-aryl-4,6-bis(methylsulfanyl)-l,3,5-thiadiazinium salts 2."... 

Some hexahydrotriazinium salts, derived from the reaction of acyl chlorides, aliphatic carbo-dimides and antimony(V) chloride, lose alkyl substituents in the 1- and 3-positions to afford the corresponding 1,3,5-triazinium hexachloroantimonates, e.g. 2 from l.15... 

Antimony(ni) is titrated to antimony(V) in neutral or slightly alkaline solution with iodine to a blue starch end point. The iodine is standardized against primary standard arsenic(in) oxide. Tartaric acid is added to complex the antimony and prevent its hydrolysis to form insoluble basic salts such as SbOCl and Sb02Cl (which form in slightly acid and neutral solution). 

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