5 - hexafluoroantimonate

Antimony forms both a trifluoride and a pentafluoride. It also forms the very stable hexafluoroantimonate ion [17111-95-4] SbF present in solution and a number of salts. 

Hexafluoroantimonic acid [72121 -43-8] HSbF 6H20, is prepared by dissolving freshly prepared hydrous antimony pentoxide ia hydrofluoric acid or adding the stoichiometric amount of 70% HF to SbF. Both of these reactions are exothermic and must be carried out carefully. 

The silver fluorocomplexes, ie, silver hexafluoroantimonate [26042-64-8], AgSbF silver hexafluorophosphate [26042-63-7], AgPF silver tetrafluoroborate [14104-20-2], AgBF and other salts such as silver trifluoromethane sulfonate [2923-28-6], CF SO Ag, and silver trifluoroacetate [2966-50-9], CF COOAg, play an important role in the synthesis of organic compounds and have gained potential industrial importance. 

These compounds perform a dual function in synthesis procedures. The introduction of a complex anion assists in the stabilization of the desired product and the generation of unique intermediates by chloride displacement, eg, silver hexafluorophosphate, AgPF, forms adducts with neutral diamagnetic organometaHics which can act as controUed sources of highly reactive cations (29). Silver hexafluoroantimonate, AgSbF, is an electrophilic... 

Other less widely used alternative diazonium salts for aryl fluoride synthesis include arenediazonium hexafluoroantimonates, ArN2SbFg, arenediazonium hexafluoroarsonates, ArN AsFg, and arenediazonium hexafluorosilicates, (ArNjljSiFg 114]... 

Conversion of an epoxide directly to an acetonide is accomplished with acetone and SnCl4 (81-86% yield) or with A-(4-methoxybenzyl)-2-cyan- opyridinium hexafluoroantimonate [A-(4-MeOC6H4CH2)-2-CN-PyrSbFJ (59-100% yield). ... 

H0(CH2)20H, PhH, A -benzylpyridinium hexafluoroantimonate, 1.5-9 h, reflux, 72-91% yield." It is also possible to form the 4,4-dimethyldiox-ane (85-99% yield) under these conditions. 

An analogous stepwise mechanism was also proposed by Wohrle [36] for the cation-radical-initiated cycloaddition of electron-rich allenes with pentamethyl-cyclopentadiene in the presence of tris (p-tolyl) aminium hexafluoroantimonate (TTA SbF6 ) (Equation 1.15). 

The reaction rate has also been greatly increased by the addition of a one-electron oxidant tris-(4-bromophenyl)aminium hexafluoroantimonate Ar3N SbF (Ar = / -bromophenyl)." This reagent converts the substrate to a cation radical, which undergoes ring expansion much faster." ... 

Replacing an a-alkyl snbstituent by an a-aryl group is expected to stabilize the cationic center by the p-Jt resonance that characterizes the benzyl carbocations. In order to analyze such interaction in detail, the cumyl cation was crystallized with hexafluoroantimonate by Laube et al. (Fig. 13) A simple analysis of cumyl cation suggests the potential contributions of aromatic delocalization (Scheme 7.3), which should be manifested in the X-ray structure in terms of a shortened cationic carbon—aromatic carbon bond distance (C Cat). Similarly, one should also consider the potential role of o-CH hyperconjugation, primarily observable in terms of shortened CH3 distances. Notably, it was found experimentally that the Cai distance is indeed shortened to a value of 1.41 A, which is between those of typical sp -sp single bonds (1.51 A) and sp -sp double bonds (1.32 A). In the meantime, a C -CH3 distance of 1.49 A is longer than that observed in the tert-butyl cation 1 (1.44 A), and very close to the normal value for an sp -sp single bond. 

Stein, L., Removal of Xenon and Radon from Contaminated Atmospheres with Dioxygenyl Hexafluoroantimonate, O SbF, Nature 243, No. 5401, 30-32 (May 4, 1973). 

Organosilicon hydride reductions of preformed stable carbocations such as triphenylmethyl (trityl) tetrafluoroborate and hexafluoroantimonate salts are rapid... 

Figure 36 Anion bridging in (a) solid tris(pentafluorophenyl) telluronium chloride and (b) dimesityl(pentafluorophenylseleno) telluronium hexafluoroantimonate...

Tetrahydrobenzyl alcohol (( )3-cyclohexenene-l-methanol) and 30% aqueous hydrogen peroxide were purchased from Fluka, AG. 3-Cyclohexene-1-carboxylic acid and cis-4-cyclohexene-l,2-dicarboxylic acid were used as purchased from Lancaster Chemical Co. Methyl iodide, acetic anhydride, Oxone (potassium peroxymonosulfate), Aliquot 336 (methyl tri-n-octylammonium chloride), sodium tungstate dihydrate and N,N-dimethylaminopyridine (DMAP) were purchased from Aldrich Chemical Co. and used as received. 3,4-Epoxycyclohexylmethyl 3, 4 -epoxycyclohexane carboxylate (ERL 4221) and 4-vinylcyclohexene dioxide were used as purchased from the Union Carbide Corp. (4-n-Octyloxyphenyl)phenyliodonium hexafluoroantimonate used as a photoinitiator was prepared by a procedure described previously (4). 

Materials. The 1-propanol, glycerol and anthracene were obtained from Aldrich Chemical Company and were used as received. As in a previous study,17 a commercially available bis-(4-dodecylphenyl) iodonium hexafluoroantimonate salt (UV9310C GE Silicones) was used as the initiator. In this initiator, various dodecyl isomers have been attached to the phenyl rings of the diphenyliodonium salt to impart solubility in the monomer and do not effect the reactivity of the initiator.1 All studies were performed with an order of magnitude excess of initiator relative to anthracene. 

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