Casteel William J., Dixon David A., Mercier Hélène P. A., Schrobilgen Gary J.
Department of Chemistry McMaster University, Hamilton, Ontario L8S 4M1, Canada, and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Battelle Memorial Insitute P.O. Box 999, KI-83, Richland, Washington 99352.
Inorg Chem. 1996 Jul 17;35(15):4310-4322. doi: 10.1021/ic951059n.
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.
二氧化四氟锇（顺式 - OsO₂F₄）在无水氢氟酸和五氟化锑溶液中与强氟离子受体五氟化砷（AsF₅）和五氟化锑（SbF₅）反应，生成橙色盐。拉曼光谱表明，分别形成了氟桥连的二锇阳离子F(cis - OsO₂F₃)₂⁺的六氟砷酸根（AsF₆⁻）盐和十一氟二锑酸根（Sb₂F₁₁⁻）盐。这些盐在氢氟酸溶液中的¹⁹F核磁共振谱是交换平均单峰，出现在比顺式 - OsO₂F₄的氟环境更高的频率处。F(cis - OsO₂F₃)₂⁺Sb₂F₁₁⁻盐结晶于正交晶系空间群Imma。在 - 107℃时，a = 12.838(3) Å，b = 10.667(2) Å，c = 11.323(2) Å，V = 1550.7(8) ų，Z = 4。精修收敛后R = 0.0469 [R(w) = 0.0500]。晶体结构由离散的氟桥连F(cis - OsO₂F₃)₂⁺和Sb₂F₁₁⁻离子组成，其中F(cis - OsO₂F₃)₂⁺阳离子的氟桥与每个OsO₂F₃基团的一个氧原子（Os - O 1.676 Å）呈反式。桥处的角度为155.2(8)度，桥连的Os---F(b)距离为2.086(3) Å。两个端基氟原子（Os - F 1.821 Å）与两个氧原子（Os - O 1.750 Å）呈顺式，OsO₂F₃基团的两个端基氟原子彼此呈反式（1.813 Å）。OsO₂F₃⁺阳离子通过¹⁹F核磁共振和纯五氟化锑溶液中的拉曼光谱进行了表征，但无法以固态形式分离出来。核磁共振和拉曼光谱结果与一个三角双锥阳离子一致，其中氧原子和一个氟原子占据赤道平面，两个氟原子处于轴向位置。密度泛函理论计算表明，F(cis - OsO₂F₃)₂⁺的晶体结构是能量最小化结构，OsO₂F₃⁺阳离子和ReO₂F₃的能量最小化结构是具有C₂ᵥ点对称性的三角双锥结构。尝试通过在无水氢氟酸中用KrF⁺AsF₆⁻对顺式 - OsO₂F₄进行氧化氟化来制备OsOF₅⁺阳离子，但未成功。
