- [(C6F5)2if2][BF4], the first salt with the electrophilic cation [(C6F5) 2if2]+: Synthesis, reactivity, and structure
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The substitution of hypervalently bonded fluorine atoms in C 6F5IF4 was performed with C6F 5BF2 and resulted in the new salt [(C6F 5)2IF2][BF4]. The iodonium(V) salt was characterized by multi-NMR and Raman spectroscopy and X-ray crystal structure analysis. The fluorinating ability of the new electrophilic cation [(C6F5)2IF2]+ was exemplified in reactions with monovalent iodine compounds (C6F 5I, p-FC6H4I, and I2) and with electron-poor tri(organyl)pnictanes ER3 (E = P, As, Sb, Bi; R = C6F5). In a heterogeneous reaction with CsF in MeCN the [(C6F5)2IF2]+ cation forms the dinuclear [{(C6F5)2IF 2}2F]+ cation.
- Frohn, Hermann-Josef,Wenda, Andre,Floerke, Ulrich
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p. 764 - 770
(2009/04/13)
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- Stabilization of homopolyatomic cations of iodine in anhydrous hydrogen fluoride
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Sodium fluoride and the Lewis acids NbF5, TaF5, and SbF5 have been used to fix precisely the levels of basicity and acidity in the solvent anhydrous HF in order to establish the acidity thresholds above which the cations I5+, I3+, and I2+ can be generated in solution. Addition of an excess of the base F- causes disproportionation of each of the cations to I2 and IF5. When these disproportionation products are dissolved in HF and the acidity level is adjusted appropriately, the individual cations can be generated. It is shown that the level of acidity is the principal determinant of the nature of the iodine cations generated in HF.
- Besida, John,O'Donnell, Thomas A.
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p. 1669 - 1673
(2008/10/08)
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- Fluorine-oxygen exchange reactions in IF5, IF7, and IF5O
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When reacted with alkali-metal nitrates, IF5 readily exchanges two fluorine ligands for a doubly bonded oxygen atom. In all cases MIF4O salts (M = Li, K, Cs) and FNO2 are formed as the primary products. The FNO2 byproduct undergoes a fast secondary reaction with MNO3 to yield equimolar amounts of N2O5 and MF. The N2O5 decomposes to N2O4 and 0.5 mol of O2, while the MF, depending on the nature of M, does or does not undergo complexation with the excess of IF5. Pure MIF4O salts, free of MF or MF·nIF5 byproducts, were prepared from MF, I2O5, and IF5 in either CH3CN or IF5 as a solvent. The new compounds LiIF4O, NaIF4O, RbIF4O, and NOIF4O were characterized by vibrational spectroscopy. It was also shown that, contrary to a previous report, FNO2 does not form a stable adduct with IF5 at temperatures as low as -78°C. An excess of IF7 reacts with MNO3 (M = Li, Na) to give MF, FNO2, IF5, and 0.5 mol of O2, but surprisingly no IF5O. With CsNO3, the reaction products are analogous, except for the CsF reacting with both the IF5 product and the excess of IF7 to give CsIF6·2IF5 and CsIF8, respectively. When in the IF7 reaction an excess of LiNO3, is used, the IF5 product undergoes further reaction with LiNO3, as described above. The IF5O molecule was found to be rather unreactive. It does not react with either LiF or CsF at 25 or 60°C or with LiNO3 or CsNO3 at 25°C. At 60°C with LiNO3, it slowly loses oxygen, with the IF5 product reacting to yield LiIF4O, as described above.
- Christe, Karl O.,Wilson, William W.,Wilson, Richard D.
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p. 904 - 908
(2008/10/08)
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- FXeOIOF4 and Xe(OIOF4)2: Preparation and study by 129Xe and 19F NMR spectroscopy and Raman spectroscopy and NMR characterization of LXeOIOF4 (L = -OTeF5, -OSO2F)
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The novel xenon(II) derivatives FXeOIOF4 and Xe(OIOF4)2 have been shown by their solution 19F and 129Xe NMR spectra to result from the reaction between IO2F3 and XeF2 in SO2ClF, CFCl3, and BrF5 solvents. The covalently bonded -QIF4O groups are shown to be equilibrium mixtures of their cis and trans isomers and are oxygen-bonded to xenon. The solid derivative cis,cis-Xe(OIOF4)2 has been isolated from the acid displacement reaction between Xe(OTeF5)2 and the strong protonic acid cis/trans-HOIOF4. In addition, a mixture of cis- and trans-FXeOIOF4 was prepared by the reaction of stoichiometric amounts of IO2F3 and XeF2 in HF solvent. Both cis- and trans-FXeOIOF4 and cis,cis-Xe(OIOF4)2 were characterized by 19F and 129Xe NMR spectroscopy and low-temperature Raman spectroscopy. A comparison of 129Xe NMR chemical shifts among Xe(II) compounds, including the mixed derivatives F4OIOXeOSO2F and F4OIOXeOTeF5, indicates the effective group electronegativity order is -F > -OSO2F > trans-OIF4O > cis-OIF4O > -OTeF5.
- Syvret, Robert G.,Schrobilgen, Gary J.
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p. 1564 - 1573
(2008/10/08)
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