558-32-7Relevant articles and documents
Tetrafluorophosphate anion
Christe, Karl O.,Dixon, David A.,Schrobilgen, Gary J.,Wilson, William W.
, p. 3918 - 3928 (1997)
The elusive POF4- anion has been characterized for the first time. It is formed from N(CH3)4F and POF3 in CHF3 solution at -140 °C and can be observed at this temperature by 19F and 31P NMR spectroscopy. Between - 140 and -100 °C it reacts with POF3 forming the OF2P-O-PF5- anion, which, at higher temperatures, reacts with F- anions to give PO2F2- and PF6-. This reaction sequence provides a low activation energy barrier pathway for the highly exothermic dismutation of pseudo-trigonal-bipyramidal POF4- to tetrahedral PO2F2- and octahedral PF6- and explains the previous failures to isolate POF4- salts. In addition to POF4-, OF2POPF5-, and PO2F2-, the protonated form of OF2POPF5-, i.e., HOF2POPF5, was also identified as a by product by NMR spectroscopy. The structure, vibrational spectra, force field, NMR parameters, and dismutation energy of POF4- were calculated by ab initio electronic structure methods using, where required, the closely related and well-known PF4- ion and POF3, PF3, SOF4, and SF4 molecules for the determination of scaling factors. Although the structures and dismutation energies of isoelectronic POF4- and SOF4 are very similar, their dismutation behavior is strikingly different. While POF4- dismutates rapidly at low temperatures, SOF4 is kinetically stable toward dismutation to SO2F2 and SF6. This fact is attributed to the lack of a low activation energy barrier pathway for SOF4. Furthermore, the dismutation energy calculations for POF4-, SOF4, and ClOF3 revealed very large errors in the previously published thermodynamic data for the heats of formations of SO2F2 and SOF4 and the dismutation reaction energy of POF4-. Energy barriers and the C(4v) transition states for the Berry-style pseudorotational exchange of equatorial and axial fluorines in POF4-, SOF4, PF4-, and SF4 were also calculated and can account for the observation that on the NMR time scale the exchange in PF4- and SF4 can be frozen out at about -40 °C, while in POF4- and SOF4 it is still rapid at -140 and -150 °C, respectively.
Towards the Prediction of Global Solution State Properties for Hydrogen Bonded, Self-Associating Amphiphiles
White, Lisa J.,Tyuleva, Stilyana N.,Wilson, Ben,Shepherd, Helena J.,Ng, Kendrick K. L.,Holder, Simon J.,Clark, Ewan R.,Hiscock, Jennifer R.
, p. 7761 - 7773 (2018/05/08)
Through this extensive structure–property study we show that critical micelle concentration correlates with self-associative hydrogen bond complex formation constant, when combined with outputs from low level, widely accessible, computational models. Herein, we bring together a series of 39 structurally related molecules related by stepwise variation of a hydrogen bond donor–acceptor amphiphilic salt. The self-associative and corresponding global properties for this family of compounds have been studied in the gas, solid and solution states. Within the solution state, we have shown the type of self-associated structure present to be solvent dependent. In DMSO, this class of compound show a preference for hydrogen bonded dimer formation, however moving into aqueous solutions the same compounds are found to form larger self-associated aggregates. This observation has allowed us the unique opportunity to investigate and begin to predict self-association events at both the molecular and extended aggregate level.
New anions of pentacoordinate phosphorus containing fluorine and trifluoromethyl groups
Pavlenko, Natalya V.,Babadzhanova, Lesya A.,Gerus, Igor I.,Yagupolskii, Yurii L.,Tyrra, Wieland,Naumann, Dieter
, p. 1501 - 1507 (2008/02/06)
The unique pseudo-trigonal-bipyramidal CF3PF3O - and (CF3)2PF2O- anions were obtained and characterised for the first time. They were formed by the reactions of (PhO)3P(O), Me3SiCF3 and the fluoride ion sources [Me4N]F and CsF, respectively, in glyme. These anions represent the stable transition states postulated for nucleophilic substitution at a tetrahedral phosphorus atom. The salt Cs[(CF3) 2PF2O] (7) is stable at room temperature for a month, while [Me4N][CF3PF3O] (1) dismutates into [Me4N][CF3PF(O)O] (2) and [Me4N][CF 3PF5] (3) above 0°C. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
