Hexafluorophosphate ion

Early examples of enantioselective extractions are the resolution of a-aminoalco-hol salts, such as norephedrine, with lipophilic anions (hexafluorophosphate ion) [184-186] by partition between aqueous and lipophilic phases containing esters of tartaric acid [184-188]. Alkyl derivatives of proline and hydroxyproline with cupric ions showed chiral discrimination abilities for the resolution of neutral amino acid enantiomers in n-butanol/water systems [121, 178, 189-192]. On the other hand, chiral crown ethers are classical selectors utilized for enantioseparations, due to their interesting recognition abilities [171, 178]. However, the large number of steps often required for their synthesis [182] and, consequently, their cost as well as their limited loadability makes them not very suitable for preparative purposes. Examples of ligand-exchange [193] or anion-exchange selectors [183] able to discriminate amino acid derivatives have also been described. 

Determination as the tetraphenylarsonium compound Discussion. Any ions forming a precipitate with tetraphenylarsonium chloride (e.g. MnO, ClOj, Br , I-, I03 and SCN-) will interfere. Difluorophosphates give slight interference which can be overcome by boiling the solution for a few minutes to hydrolyse difluorophosphate the hexafluorophosphate ion is not affected by this treatment. 

Construction of discrete and well-defined molecular architectures using organic ligands and metal ions through the self-assembly route has received much attention. A dinuclear Pd11 cage,636 includes a hexafluorophosphate ion inside the cavity. Self-assembly of a novel macrotricyclic cage... 

Perchlorate and nitrate, as well as the halides, are less mobile relative to their size than the tetrafluoroborate and hexafluorophosphate ions. Anions that lie below the upper curve in Fig. 3 appear to undergo interaction with acetonitrile to a greater extent than would be expected on the basis of simple charge-dipole interaction, but the nature of this interaction is difficult to postulate. The fluoro ions should less likely undergo specific interactions. Because the differences in mobilities are not great, however, extensive speculation is unwarranted. 

Electron pairs can also be donated into d orbitals, when these orbitals are available. For example, numerous compounds are known containing the complex hexafluorophosphate ion, PF(). This ion is readily produced from... 

E. O. Fischer was the first to prepare arene complexes of technetium. Arene ligands in these compound are typically six-electron donors. The nature of the Tc-arene bond is probably very similar to the one of the Tc-Cp bond. The [Tc(arene)2] complexes (arene = benzene or hexamethylbenzene) are prepared by the reaction of TcCLt with the appropriate arene in the presence of AICI3/AI. In a typical reaction, TcCLt, AICI3, and aluminum were heated with benzene in a sealed tube to 135 °C for two days. The product is precipitated as a salt using the hexafluorophosphate ion. A variety of other 18-electron compounds can be prepared from this material, particularly through chemical reduction. 

The Group VIA elements below oxygen form some covalent compounds of the ABg type by sharing their six valence electrons with six other atoms. Sulfur hexafluoride, SFg (mp — 51 °C), an unreactive gas, is an example. Sulfur hexafluoride molecules are nonpolar octahedral molecules. The hexafluorophosphate ion, PFg, is an example of a polyatomic ion of the type AB. ... 

The hexafluorophosphate ion has proved to be very useful for studies with complexes, since the [PF6] anion has a very weak coordinating ability.1 Lan-thanoid hexafluorophosphates can be obtained in very concentrated aqueous solutions by reaction of a freshly prepared solutions of hexafluorophosphoric acid and a hydrated lanthanoid basic carbonate.2 The resulting solution, after filtration, is evaporated to near dryness. Attempts to isolate the hydrated salts are unsuccessful because of decomposition accompanied by hydrogen fluoride evolution. Nevertheless, the complexes containing diphenylphosphinic amide are isolable and are quite stable.3... 

Fluorophosphates. As with many other oxo anions, fluorine can replace OH in phosphate to give mono- and di-fluorophosphate salts and esters. The dialkyl monofluorophosphate esters have been found to inhibit cholinesterase in the body and to be exceedingly toxic. The hexafluorophosphate ion, PFg, has been discussed (page 376). 

These dehydrofluorination reactions are particularly interesting in view of reports of the oxidation of certain fluorophosphines to derivatives of the hexafluorophosphate ion by bifluoride ion (235, 238, 249), namely,... 

Counterions of ILs could be facilely exchanged in solution, thus based on a surfactant with an imidazolium unit, the ion-exchange reaction from bromine ion to hexafluorophosphate ion resulted in the amphiphilic-to-hydrophobic transition of the imidazolium... 

On the other hand phosphorus(V) fluoride gives the hexafluorophosphate ion in solutions of bromine(III) fluoride. Thus phosphorus(V) chloride is a solvo-... 

---