Pyridinium hexafluorophosphate

HATU = l-[his(dimethylamino)methylene]-lH l,2,3-triazolo-[4,5,6]pyridinium hexafluorophosphate 3-oxide (Applied Biosystems). 

N-tetradecyl pyridinium hexafluorophosphate 1107-51 N-hexadecyl pyridinium hexafluorophosphate... 

In an interesting experiment, Yagci et al. polymerized cyclohexene oxide (CHO) via a photosensitized cationic polymerization with an initiator that contained a TEMPO moiety capable of CRP [281]. Anthracene was reacted with N-ethoxy-2-methyl pyridinium hexafluorophosphate, which produced a radical cation that could then be trapped with TEMPO to create the dual initiating species capable of both cationic and nitroxide-mediated polymerizations (Scheme36). 

CsHgClNO, Pyridine-N-oxide hydrochloride, 24, 690 26, 703 CsHgFgNP, Pyridinium hexafluorophosphate(V), 31B, 120... 

Separation science focuses on room temperature ionic liquids (RTlLs), salts that are liquid at ambient temperature. They have been studied as extracting solvents, stationary and mobile phases, mobile phase additives, and other uses. Common RTILs consist of a bulky nitrogen- or phosphorus-containing organic cation (pyridinium or pyrrolidinium, alkyl-imidazolium, ammonium or phosphonium) and a variety of organic and inorganic anions (triflate, dicyanamide, trifluoroacetate, acetate trifluo-romethylsulfate, nitrate, perchlorate, bromide, chloride, chloroaluminate, tetrafluo-roborate, hexafluorophosphate). 

Synonyms HOAt l-Hydroxy-lH-v-triazolo[4, 5-b]pyridine 7-Aza-l-hydroxybenzotriazole [1,2, 3]Triazolo[4,5-6]pyridin-3-ol 3-Hydroxy-3H-l,2, 3-triazolo[4,5-6]pyridine HATU lH-l,2,3-Triazo-lo [4,5-6]pyridinium, 1 - [bis( dimethylamino)methyl-ene]-, hexafluorophosphate 1-), 3-oxide HATU may crystallize as guanidinimum N-oxides N-form), rather than the isomeric uranium structures (0-form) depending on storage conditions N-[(di-methylamino)-lH-l,2,3-triazolo[4,5-fc]pyridine-l-yl-methylene] -N-methylmethanaminium hexafluorophosphate. PyAOP Tri-l-pyrrolidinyl(3H-... 

Fig. 3 Schematic representation of the transferability premise developed as a built-in characteristic of the CLAP force-field, a cl, c2, c3, and c4 stand for imidazolium- pyridinium-, phosphonium- and guanidinium-based cations, al to a5 stand for the hexafluorophosphate, chloride, nitrate, bis-(trifluoromethanesulfonil)imide, and triflate anions. The c3-a4 combination was selected in this case, b The possibility to grow an alkyl side chain in, for example, imidazolium-based ionic liquids in order to study an entire homologous series of ionic liquids is illustrated...

In order to study the mutual solubilities of hydrophobic but also hygroscopic imida-zolium-, pyridinium-, pyrrolidinium-, and piperidinium-based ILs in combination with the anions bis-(trifhioromethylsulfonyl)imide, hexafluorophosphate, and tricy-anomethane with water, UV spectroscopic measurements were carried out at temperatures between 288.15 and 318.15 K. Continuum model calculations were used to support these measurements of the Gibbs energy, enthalpy, and entropy. It was found that the hydrophobic tendency increases from imidazolium to pyridinium to pyrrolidinium to piperidinium and with increasing alkyl chain length within the same cation-varying anion ion pair [157],... 

All the physico-chemical properties strictly dependent upon the precise nature of the cation and anion constituting the IL and they can be changed or modulated by changing the anion or cation or modifying the nature of substituents on cation. Structurally, most of the ILs that have been investigated to date are based on imidazolium, ammonium and pyridinium cations, bearing alkyl chains, associated with polyatomic anions such as chloroaluminates, tetrafluoroborate, hexafluorophosphate and bis-triflimide. In Scheme 1 are reported the above mentioned cations and anions whose combination gives the most commonly employed ionic liquids. 

In 2005, Legeay and his coworkers reported the preparation of two new types of task-specific ionic fiqnids, l-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate or hexafluorophosphate and N-(2- hydroxyethyl)-pyridinium tetrafluoroborate 3c or hexafluorophosphate ([PEGj-mim][X] and [PEGj-py][X]), via an efficient method, which is shown in Eig. 12.51. [34],... 

The effects of increasing the concentration of initiator (i.e. increased conversion, decreased and broader PDi) and reducing the reaction temperature (i.e. decreased conversion, increased M and narrower PDi) for the polymerizations in ambient-temperature ionic Uquids are the same as observed in conventional solvents. Mays et al. reported similar results and, in addition, used NMR to investigate the stereochemistry of the PMMA produced in (BMIMjlPFej. They found that the stereochemistry is almost identical to that for PMMA produced by free radical polymerization in conventional solvents [28]. The homopolymerization and copolymerization of several other monomers are also reported. Similar to vdiat was found by Noda and Watanabe, in many cases the polymer was not soluble in the ionic liquid and thus phase separated [28,29]. Free radical polymerization of n-butyl methacrylate in ionic liquids based on imidazolium, pyridinium, and alkylammonium salts as solvents was investigated with a systematic variation of the length of the alkyl substituents on the cations, and employing different anions such as tetrafluoroborate, hexafluorophosphate, tosylate, triflate, alkyl sulfates and dimethyl phosphate [31]. 

Salts that melt at temperatures below 100°C form useful ionic liquids (ILs) [29]. Because they lack measurable vapor pressure (even up to 300°C), the ILs can be used as green solvents or reaction media. As a result, they have recently received a lot of attention [30]. Simple ILs usually contain imidazolium, pyridinium, or organic ammonium cations. The anions could be chloride, bromide, or more complex structures such as hexafluorophosphate, trifluoromethyl-sulfonate, bis(trifluoro-methylsulfonyl)imide [31]. 

Electrophilic iodine reagents have also been employed in iodocyclization. Several salts of pyridine complexes with such as bis(pyridinium)iodonium tetrafluoroborate and bis(collidine)iodonium hexafluorophosphate have proven especially effective. y-Hydroxy- and (3-hydroxyalkenes can be cyclized to tetrahydrofuran and tetrahydropyran derivatives, respectively, by positive halogen reagents. (see entries 6 and 8 in Scheme 4.2). 

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