Raman study of the O2F2 + VF5 reaction: Isolation and identification of an unstable reaction intermediate

Syntheses of Dioxygenyl Salts by Photochemical Reactions in Liquid Anhydrous Hydrogen Fluoride: X-ray Crystal Structures of α- and β-O2Sn2F9, O2Sn2F9·0.9HF, O2GeF5·HF, and O2[Hg(HF)]4(SbF6)9

By treating gaseous, liquid, or solid fluorides with UV-photolyzed O₂/F₂ mixtures and by treating solid oxides with UV-photolyzed F₂ (or O₂/F₂ mixtures) in liquid anhydrous HF at ambient temperature, we investigated the possibility of the preparation of O₂M^IIIF₄ (M = B, Fe, Co, Ag), O₂M^IVF₅ (M = Ti, Sn, Pb), (O₂)₂M^IVF₆ (M = Ti, Ge, Sn, Pb, Pd, Ni, Mn), O₂M^IV₂F₉ (M = Sn), O₂M^VF₆ (M = As, Sb, Au, Pt), O₂M^V₂F₁₁ (M = Pt), O₂M^VIF₇ (M = Se), (O₂)₂M^VIF₈ (M = Mo, W), and O₂M^VIIF₈ (M = I). The approach has been successful in the case of previously known O₂BF₄, O₂MF₆ (M = As, Sb, Au; Pt), O₂GeF₅, and (O₂)₂(Ti₇F₃₀). Novel compounds O₂GeF₅·HF, α-O₂Sn₂F₉ (1-D), and the HF-solvated and nonsolvated forms of β-O₂Sn₂F₉ (2-D) were synthesized and their crystal structures determined using single-crystal X-ray diffraction. The crystal structures of all of these materials arise from the condensation of octahedral MF₆ (M = Ge, Sn) units. The anion in the crystal structure of O₂GeF₅·HF is comprised of infinite ([GeF₅]⁻)_∞ chains of GeF₆ octahedra that share common vertices. The HF molecules and O₂⁺ cations are located between the chains. The crystal structure of α-O₂SnF₉ (1-D) is constructed from [O₂]⁺ cations and polymeric ([Sn₂F₉]⁻)_∞ anions which appear as two parallel infinite chains comprised of SnF₆ units, where each SnF₆ unit of one chain is connected to a SnF₆ unit of the second chain through a shared fluorine vertex. The single-crystal structure determination of [O₂][Sn₂F₉]·0.9HF reveals that it is comprised of two-dimensional ([Sn₂F₉]⁻)_∞ grids with [O₂]⁺ cations and HF molecules located between them. The 2-D grids have a wavelike conformation. The ([Sn₂F₉]⁻)_∞ layer contains both six- and seven-coordinated Sn(IV) atoms that are interconnected by bridging fluorine atoms. A new, more complex [O₂]⁺ salt, O₂[Hg(HF)]₄[SbF₆]₉, was prepared. In its crystal structure, the Hg atoms bridge to SbF₆ units to form a 3-D framework. The O₂⁺ cations are located inside the voids while the HF molecules are bound to Hg atoms through the F atom. Attempts to prepare several chlorine analogues of O₂⁺ fluorine salts (i.e., O₂TiCl₅ and O₂MCl₆ (M = Nb, Sb)) failed.

Reactions between fluorides and/or oxides and UV-irradiated F₂ and/or F₂/O₂ mixtures were carried out in anhydrous hydrogen fluoride at ambient temperature to prepare O₂⁺ salts. The crystal structures of O₂GeF₅·HF and O₂GeF₅ consist of infinite polymeric ([GeF₅]⁻)_∞ anions. The O₂Sn₂F₉ salt exhibits polymorphism consisting of a 1-D phase built from double chainlike ([Sn₂F₉]⁻)_∞ anions and a 2-D phase built from layerlike anions. The latter also exists as a solvated form O₂Sn₂F₉·nHF. The crystal structure of O₂[Hg(HF)]₄(SbF₆)₉ is isotypic to that of H₃O[Cd(HF)]₄(SbF₆)₉. The Hg atoms are bridged by SbF₆ groups forming a 3-D framework with O₂⁺ cations located inside the voids. The HF molecules are bound to Hg atoms through the F atom.

The Osmium(VIII) Oxofluoro Cations OsO(2)F(3)(+) and F(cis-OsO(2)F(3))(2)(+): Syntheses, Characterization by (19)F NMR Spectroscopy and Raman Spectroscopy, X-ray Crystal Structure of F(cis-OsO(2)F(3))(2)(+)Sb(2)F(11)(-), and Density Functional Theory Calculations of OsO(2)F(3)(+), ReO(2)F(3), and F(cis-OsO(2)F(3))(2)(+)

Osmium dioxide tetrafluoride, cis-OsO(2)F(4), reacts with the strong fluoride ion acceptors AsF(5) and SbF(5) in anhydrous HF and SbF(5) solutions to form orange salts. Raman spectra are consistent with the formation of the fluorine-bridged diosmium cation F(cis-OsO(2)F(3))(2)(+), as the AsF(6)(-) and Sb(2)F(11)(-) salts, respectively. The (19)F NMR spectra of the salts in HF solution are exchange-averaged singlets occurring at higher frequency than those of the fluorine environments of cis-OsO(2)F(4). The F(cis-OsO(2)F(3))(2)(+)Sb(2)F(11)(-) salt crystallizes in the orthorhombic space group Imma. At -107 degrees C, a = 12.838(3) Å, b = 10.667(2) Å, c = 11.323(2) Å, V = 1550.7(8) Å(3), and Z = 4. Refinement converged with R = 0.0469 [R(w) = 0.0500]. The crystal structure consists of discrete fluorine-bridged F(cis-OsO(2)F(3))(2)(+) and Sb(2)F(11)(-) ions in which the fluorine bridge of the F(cis-OsO(2)F(3))(2)(+) cation is trans to an oxygen atom (Os-O 1.676 Å) of each OsO(2)F(3) group. The angle at the bridge is 155.2(8) degrees with a bridging Os---F(b) distance of 2.086(3) Å. Two terminal fluorine atoms (Os-F 1.821 Å) are cis to the two oxygen atoms (Os-O 1.750 Å), and two terminal fluorine atoms of the OsO(2)F(3) group are trans to one another (1.813 Å). The OsO(2)F(3)(+) cation was characterized by (19)F NMR and by Raman spectroscopy in neat SbF(5) solution but was not isolable in the solid state. The NMR and Raman spectroscopic findings are consistent with a trigonal bipyramidal cation in which the oxygen atoms and a fluorine atom occupy the equatorial plane and two fluorine atoms are in axial positions. Density functional theory calculations show that the crystallographic structure of F(cis-OsO(2)F(3))(2)(+) is the energy-minimized structure and the energy-minimized structures of the OsO(2)F(3)(+) cation and ReO(2)F(3) are trigonal bipyramidal having C(2)(v)() point symmetry. Attempts to prepare the OsOF(5)(+) cation by oxidative fluorination of cis-OsO(2)F(4) with KrF(+)AsF(6)(-) in anhydrous HF proved unsuccessful.