Hexafluorophosphate

Dicarbonyl-/i5-cyclopentadienylnitrosylmanganese(l + ) hexafluoro-phosphate(l —) is usually prepared1 by the reaction of tricarbonyl-fi5-cyclopentadienylmanganese with sodium nitrite and hydrochloric acid in refluxing ethanol. The cationic nitrosyl is isolated by the addition of ammonium hexafluorophosphate to the reaction mixture. This procedure yields up to 50 % of the product in a total reaction time of several hours. A more efficient preparation is the direct reaction of [Mn(C5H5)(CO)3] with [NO][PF6] in acetonitrile, which allows the isolation of the cationic complex in quantitative yield in less than one hour. 

The reaction is conducted in an atmosphere of dry nitrogen, and the acetonitrile must be dried before use (molecular sieves are satisfactory), since nitrosyl hexafluorophosphate is easily hydrolyzed. To 2 g. of tricarbonyl- -cyclopentadienylmanganese1 in 100 ml. of acetonitrile is added dropwise, and with rapid stirring, a solution of 1.9 g. [NO] [PF6] in 30 ml. of acetonitrile. Carbon monoxide is evolved, and the solution becomes darker yellow. After the addition of the [NO][PF6] solution is complete (5 minutes), stirring is continued for 10 minutes to ensure complete reaction. The volume of the solvent is reduced to approximately 20 ml. by evaporation, 

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. 

Procedure. To an aliquot containing 36-55 mg of potassium hexafluorophosphate add aqueous ammonia until the solution is basic. A final concentration 

The starting dimer is prepared by the published procedure5f,g or obtained commercially (Strem). The crude dimer should be recrystallized from CH2Cl2-heptane as follows It is first dissolved in a minimum volume of 

Sodium amalgam (1%) is produced by adding Na chunks to the requisite amount of mercury, which is being stirred in a 500-mL three-necked amalgam-reduction flask.6 This flask is equipped with a stopcock at the bottom to remove amalgam after completion of reaction. 

After cooling to room temperature, the amalgam (now having the consistency of liquid mercury) is drained through the bottom stopcock into a stoppered storage vessel. 

A yellow-brown suspension of NaCl results. After sitting for another 30 min, the THF suspension is filtered through an 8-cm Celite pad, which is further washed with CH2C12 (5 x 25 mL). 

The combined filtrates containing FeCp(CO)2 CH2C(CH3)=CH2 should be protonated immediately no attempt should be made to remove the solvent or otherwise to store this crude allylic complex. 

Koubachi, J. Berteina-Raboin, S. Mouaddib, A. Guillaumet, G., Synthesis 2009,0271. 

Form Supplied in yellow powder, not commercially available. 

Preparation prepared by adding phenanthrolinium hexafluorophosphate (3 equiv) to a filtered solution of Pd(OAc)2 (1 equiv) in acetone at room temperature. The complex readily precipitates as a yellow solid and is isolated by filtration. 

Handling, Storage, and Precautions stable under regular storage conditions air and moisture stable. 

Direct Arylation of Imidazo[l,5-a]pyridines. The title compound has demonstrated excellent catalytic activity for the arylation of various itnidazo[l,5-a]pyridines with aryl iodides at the C-3 or C-1 positions. Initially, 3-(pyridin-2-yl)imidazo[l,5-a]pyridine 1 was arylated at the C-1 position in the presence of catalytic Pd(phen)2(PFe)2 and 2 equiv CS2CO3 in DMA at 150 °C (eq 1). Then, similar reaction conditions were applied to the C-1 arylation of unsubstituted imidazo[l,5-a]pyridine 2 (eq 2). A variety of aryl iodides were tolerated in the latter transformation. A one-pot, sequential arylation with 4-iodoanisole and 4-iodobenzotrifluoride, respectively, was successful in 61% yield.  

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Phosphorus pentafluoride PF will readily accept an electron pair from a fluoride ion F to form the stable hexafluorophosphate(V) anion PF C. This ion is isoelectronic with SF. and neither SF nor PF show any notable tendency to accept further electron pairs, though there is some evidence for the existence of an SF ion. 

Pentamethylbenzene and anthracene react very rapidly with nitronium tetrafluoroborate in sulpholan to give cr-complexes, which decompose slowly (see below), and durene behaves similarly with nitronium hexafluorophosphate in acetonitrile. ... 

A number of salts of the monofluoro- and hexafluorophosphoric acids are known and some are commercially important. The salts of difluorophosphoric acid are typically less stable toward hydrolysis and are less well characterized. Sodium monofluorophosphate [7631-97-2] the most widely used dentifrice additive for the reduction of tooth decay, is best known (see Dentifrices). Several hexafluorophosphates can be prepared by neutralization of the appropriate base using hexafluorophosphoric acid. The monofluorophosphates are usually prepared by other methods (57) because neutralization of the acid usually results in extensive hydrolysis. 

The NH4PO2F2 can be extracted from the soHd reaction product with boiling methanol (80). Alkali metal difluorophosphates are prepared from the hexafluorophosphates by one of the following fusion reactions (81) ... 

Hexafluorophosphates. There is a great deal of interest in the hexafluorophosphate anion [1691-18-8], mostly as organic hexafluorophosphates for catalysis in photopolymerization. A number of the compounds are diazonium compounds (see Photoreactivepolymers). 

The hexafluorophosphates are among the most stable halogen complexes known. The highly symmetrical PF ion is stable to boiling aqueous alkaH and is decomposed only slowly in acidic solutions at ambient temperatures. It does hydrolyze rapidly at elevated temperatures in acid (85). The stabiHty of the PF 3 ion can be compared to the isoelectronic SF. The hexafluorophosphates can be decomposed yielding PF although in many cases only at temperatures where the PF reacts with the metal containers. Benzenediazonium hexafluorophosphate can be decomposed to PF, N2, and fluorobenzene at 120°C (86) and is a convenient source for laboratory amounts of PF as well as a frequently used catalyst. 

Many of the organic and inorganic hexafluorophosphates can be prepared by reaction of hexafluorophosphoric acid and the appropriate base. Another method involves reaction of the appropriate chloride and PCI3 with anhydrous HF (87). 

Anhydrous silver hexafluorophosphate [26042-63-7] AgPF, as well as other silver fluorosalts, is unusual in that it is soluble in ben2ene, toluene, and xylene and forms 1 2 molecular crystalline complexes with these solvents (91). Olefins form complexes with AgPF and this characteristic has been used in the separation of olefins from paraffins (92). AgPF also is used as a catalyst. Lithium hexafluorophosphate [21324-40-3] LiPF, as well as KPF and other PF g salts, is used as electrolytes in lithium anode batteries (qv). 

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... 

Protonic initiation is also the end result of a large number of other initiating systems. Strong acids are generated in situ by a variety of different chemistries (6). These include initiation by carbenium ions, eg, trityl or diazonium salts (151) by an electric current in the presence of a quartenary ammonium salt (152) by halonium, triaryl sulfonium, and triaryl selenonium salts with uv irradiation (153—155) by mercuric perchlorate, nitrosyl hexafluorophosphate, or nitryl hexafluorophosphate (156) and by interaction of free radicals with certain metal salts (157). Reports of "new" initiating systems are often the result of such secondary reactions. Other reports suggest standard polymerization processes with perhaps novel anions. These latter include (Tf)4Al (158) heteropoly acids, eg, tungstophosphate anion (159,160) transition-metal-based systems, eg, Pt (161) or rare earths (162) and numerous systems based on tri flic acid (158,163—166). Coordination polymerization of THF may be in a different class (167). 

The principal electrophiles to attack ring sulfur are either oxidants or alkylating reagents. Thiophene sulfoxide and sulfone formation is discussed in Section 3.02.2.6. Alkylating agents capable of forming thiophenium salts include trimethyloxonium tetrafluoroborate (MeaO BF ) and alkyl fluorosulfonates (ROSO2F). The salts e.g. 87) are conveniently isolated as hexafluorophosphates (88). 

Tetraselenafulvalene, tetramethyl-, hexafluorophosphate-, TCNQ salt X-ray, 1, 355 <79AX(B)772>... 

S-Methylthiophenium hexafluorophosphate synthesis, 4, 765 Methyprylone as sedative, 1, 165 Methyridine... 

Phosphonium hexafluorophosphate, benzotriazolyl-N-hydroxytris(dimethylamino)-in peptide synthesis, 5, 728 Phosphonium salts chromene synthesis from, 3, 753 reactions, 1, 531 Phosphonium salts, vinyl-in pyrrole synthesis, 4, 343 Phosphonium ylides in heterocyclic synthesis, 5, 165 Phosphoramide, triethylene-as pharmaceutical, 1, 157 Phosphoramide, triethylenethio-as pharmaceutical, 1, 157 Phosphorane, pentaphenyl-synthesis, 1, 532 Phosphoranes, 1, 527-537 Berry pseudorotation, 1, 529 bonding, 1, 528... 

Tetra-n-butylammonium hexafluorophosphate [3109-63-5] M 387.5, m 239-241 . Recrystd from satd EtOH/water and dried for lOh in vac at 70°. It was also recrystd three times from abs EtOH and dried for 2 days in a drying pistol under vac at boiling toluene temperature [Bedard and Dahl J Am Chem Soc 108 5933 1986],... 

Ammonium hexafluorophosphate [16941-11-0] M 163.0, d 2.181, pK j 0.5, pKj 5.12 (for fluorophosphoric acid H2PO3F). Crystallises from H2O in square plates. Decomposes on heating before melting. Soluble in H2O at 20° (74.8% w/v), also very soluble in Mc2CO, MeOH, EtOH and MeOAc and is decomposed by boiling acids. [Chem Ber 63 1063 1930.]... 

Benzotriazol-l-yloxytris(dimethylamino)phosphonium hexafluorophosphate (BOP reagent)... 

Potassium hexafluorophosphate [ 17084-13-8 j M 184.1, pK 0.5, pK j 5.12 (for fluorophosphoric acid H2PO3F). Crystd from alkaline aqueous solution, using polyethylene vessels, or from 95% EtOH, and dried in a vacuum desiccator over KOH. 

Hexafluorophosphate and tetrafluoroborate dienyl salts react with many nucleophiles. The tetrafluoroborate salts are to be preferred, being more soluble in organic solvents than the hexafluorophosphates. 

New diazotization techniques for the Balz-Schiemann reaction feature alter native mtrosating agents in place of aqueous sodium nitrite or substitution of other salts such as arenediazonium hexafluorophosphates for arenediazoniuin fluoroborates... 

Arenediazonium hexafluorophosphates represent a promising alternative to diazonium fluoroborates because of decreased water solubility and, in some instances, higher yields of fluoroaromatics [27, 28] (equation 6)... 

Depending on structure, photolysis of films of arenediazonium fluoroborates and hexafluorophosphates at room temperature gives aryl fluorides m 10-75% yield [32] In situ photochemical decomposition of arenediazonium fluoroborates... 

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