13776-62-0Relevant articles and documents
Dinitrogen difluoride chemistry. Improved syntheses of cis- and trans-N2F2, Synthesis and characterization of N 2F+Sn2F9-, ordered crystal structure of N2F+Sb2F11 -, High-level electronic structure calculations of cis-N 2F2
Christe, Karl O.,Dixon, David A.,Grant, Daniel J.,Haiges, Ralf,Tham, Fook S.,Vij, Ashwani,Vij, Vandana,Wang, Tsang-Hsiu,Wilson, William W.
, p. 6823 - 6833 (2010)
N2F+ salts are important precursors in the synthesis of N5+ compounds, and better methods are reported for their larger scale production. A new, marginally stable N2F + salt, N2F+Sn2F9 -, was prepared and characterized. An ordered crystal structure was obtained for N2F+Sb2F11-, resulting in the first observation of individual N - N and N-F bond distances for N2F+ in the solid phase. The observed N - N and N-F bond distances of 1.089(9) and 1.257(8) A, respectively, are among the shortest experimentally observed N-N and N-F bonds. High-level electronic structure calculations at the CCSD(T) level with correlation-consistent basis sets extrapolated to the complete basis limit show that cis-N2F 2 is more stable than trans-N2F2 by 1.4 kcal/mol at 298 K. The calculations also demonstrate that the lowest uncatalyzed pathway for the trans-cis isomerization of N2F2 has a barrier of 60 kcal/mol and involves rotation about the N - N double bond. This barrier is substantially higher than the energy required for the dissociation of N2F2 to N2 and 2 F. Therefore, some of the N2F2 dissociates before undergoing an uncatalyzed isomerization, with some of the dissociation products probably catalyzing the isomerization. Furthermore, it is shown that the trans-cis isomerization of N2F2 is catalyzed by strong Lewis acids, involves a planar transition state of symmetry Cs, and yields a 9:1 equilibrium mixture of cis-N2F2 and trans-N2F2. Explanations are given for the increased reactivity of cis-N2F 2 with Lewis acids and the exclusive formation of cis-N 2F2 in the reaction of N2F+ with F-. The geometry and vibrational frequencies of the F2N - N isomer have also been calculated and imply strong contributions from ionic N2F+ F- resonance structures, similar to those in F3NO and FNO.
Theoretical Evidence for Two New Intermediate Xenon Species: Xenon Azide Fluoride, FXe(N3), and Xenon Isocyanate Fluoride, FXe(NCO)
Schulz, Axel,Klap?tke, Thomas M.
, p. 1929 - 1933 (2008/10/09)
The reaction behavior of xenon difluoride, XeF2, toward HN3, NaN3, and NaOCN was investigated in H2O, aHF (anhydrous HF), and SO2ClF solution. The analysis of the final reaction products (XeF2 + HN3 (NaN3) in H2O → HF, N2, N2O, Xe; XeF2 + HN3 in aHF → N2, Xe, N2F2; XeF2 + HOCN (NaOCN) in H2O → HF, N2, N2O, NH3, CO2, Xe) indicated the intermediate formation of FXe(N3) and FXe(NCO) and revealed different reaction mechanisms for both compounds. Both intermediates, FXe(N3) and FXe(NCO), were studied on the basis of ab initio computations at HF and correlated MP2 levels using a quasirelativistic LANL2DZ pseudopotential for Xe. Both were shown to possess stable minima at HF and MP2 levels (no imaginary frequencies) with the following structural parameters (MP2/LANL2DZ). FXe(N3): Cs; d(F-Xe) = 2.051, d(Xe-N1) = 2.318, d(N1-N2) = 1.241, d(N2-N3) = 1.180 ?; s; d(F-Xe) = 2.024, d(Xe-N) = 2.206, d(N-C) = 1.194, d(C-N) = 1.231 ?; -1.
Coordinatively saturated fluoro cations. Oxidative fluorination reactions with KrF+ salts and PtF6
Christe, Karl O.,Wilson, William W.,Wilson, Richard D.
, p. 2058 - 2063 (2008/10/08)
The usefulness of KrF+ salts and PtF6 as oxidative fluorinators for the syntheses of the coordinatively saturated complex fluoro cations NF4+, ClF6+, and BrF6+ was studied. The syntheses of NF4SbF6, NF4AsF6, NF4BF4, and NF4TiF5·nTiF4 from KrF2-Lewis acid adducts and NF3 were investigated under different reaction conditions. The fluorination of NF3 by KrF+SbF6- in HF solution was found to proceed quantitatively at temperatures as low as -31°C, indicating an ionic two-electron oxidation mechanism. An improved synthesis of KrF+MF6- (M = As, Sb), Raman data and solubilities in HF, and the existence of a Kr2F3+·nKrF2BF 4- adduct in HF at -40°C are reported. Attempts to fluorinate OF2, CF3NF2, and ClF4O- with KrF+ salts were unsuccessful. Whereas KrF+ is capable of oxidizing NF3, ClF5, and BrF5 to the corresponding complex fluoro cations, PtF6 was shown to be capable of oxidizing only NF3 and ClF5. Since the yield and purity of the NF4+ fluoroplatinate salts obtained in this manner were low, NF4PtF6 was also prepared from NF3, F2, and PtF6 at elevated temperature and pressure. General aspects of the formation mechanisms of coordinatively saturated complex fluoro cations are discussed briefly.
