| Abstract
| - Both TcO2F3 and ReO2F3 are fluoride ion donors toward AsF5 and SbF5, leading to the formation of stable fluorine-bridged MO2F3·PnF5 adducts (M = Tc, Re; Pn = As, Sb) in the solid state and solvated MO2F2+ cations in HF and SbF5 solvents. The ReO2F3·SbF5 adduct ionizes in CH3CN and SO2ClF solvents to form the cis-ReO2F2(CH3CN)2+ and fluoride-bridged Re2O4F5+ cations, respectively.
- The fluoride ion donor properties of TcO2F3 and ReO2F3 toward AsF5, SbF5, and XeO2F2 have been investigated,leading to the formation of TcO2F3·PnF5 and ReO2F3·PnF5 (Pn = As, Sb) and TcO2F3·XeO2F2, which werecharacterized in the solid state by Raman spectroscopy and X-ray crystallography. TcO2F3·SbF5 crystallizes inthe monoclinic system P21/n, with a = 7.366(2) Å, b = 10.441(2) Å, c = 9.398(2) Å, β = 93.32(3)°, V =721.6(3) Å3, and Z = 4 at 24 °C, R1 = 0.0649, and wR2 = 0.1112. ReO2F3·SbF5 crystallizes in the monoclinicsystem P21/c, with a = 5.479(1) Å, b = 10.040(2) Å, c = 12.426(2) Å, β = 99.01(3)°, V = 675.1(2) Å3, and Z= 4 at −50 °C, R1 = 0.0533, and wR2 = 0.1158. TcO2F3·XeO2F2 crystallizes in the orthorhombic system Cmc21,with a = 7.895(2) Å, b = 16.204(3) Å, c = 5.198(1) Å, β = 90°, V = 665.0(2) Å3, and Z = 4 at 24 °C, R1 =0.0402, and wR2 = 0.0822. The structures of TcO2F3·SbF5 and ReO2F3·SbF5 consist of infinite chains of alternatingMO2F4 and SbF6 units in which the bridging fluorine atoms on the antimony are trans to each other. The structureof TcO2F3·XeO2F2 comprises two distinct fluorine-bridged chains, one of TcO2F3 and the other of XeO2F2 bridgedby long Tc−F···Xe contacts. The oxygen atoms of the group 7 metals in the three structures are cis to each otherand to two terminal fluorine atoms and trans to the bridging fluorine atoms. The 19F NMR and Raman spectra ofTcO2F3·PnF5 and ReO2F3·PnF5 in SbF5 and PnF5-acidified HF solvents are consistent with dissociation of theadducts into cis-MO2F2(HF)2+ cations and PnF6- anions. The energy-minimized geometries of the free MO2F2+cations and their HF adducts, cis-MO2F2(HF)2+, have been calculated by local density functional theory (LDFT),and the calculated vibrational frequencies have been used as an aid in the assignment of the Raman spectra of thesolid MO2F3·PnF5 adducts and their PnF5-acidified HF solutions. In contrast, ReO2F3·SbF5 ionizes in SO2ClFsolvent to give the novel Re2O4F5+ cation and Sb2F11- anion. The 19F NMR spectrum of the cation is consistentwith two ReO2F2 units joined by a fluorine bridge in which the oxygen atoms are assumed to lie in the equatorialplane. The [ReO2F2(CH3CN)2][SbF6] salt was formed upon dissolution of ReO2F3·SbF5 in CH3CN and wascharacterized by 1H, 13C, and 19F NMR and Raman spectroscopies. The ReO2F2(CH3CN)2+ cation is apseudooctahedral cis-dioxo arrangement in which the CH3CN ligands are trans to the oxygens and the fluorinesare trans to each other.
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