Noble-Gas Difluoride Complexes of Mercury(II): The Syntheses and Structures of Hg(OTeF₅)₂·1.5NgF₂ (Ng = Xe, Kr) and Hg(OTeF₅)₂

Abstract

The synthesis of high-purity Hg(OTeF5)2 has resulted in its structural characterization in the solid state by Raman spectroscopy and single-crystal X-ray diffraction (XRD) and in solution by (19)F NMR spectroscopy. The crystal structure of Hg(OTeF5)2 (-173 °C) consists of discrete Hg(OTeF5)2 units having gauche-conformations that interact through long Hg---O and Hg---F intramolecular contacts to give a chain structure. The Lewis acidity of Hg(OTeF5)2 toward NgF2 (Ng = Xe, Kr) was investigated in SO2ClF solvent and shown to form stable coordination complexes with NgF2 at -78 °C. Both complexes were characterized by low-temperature Raman spectroscopy (-155 °C) and single-crystal XRD. The complexes are isostructural and are formulated as Hg(OTeF5)2·1.5NgF2. The Hg(OTeF5)2 units of Hg(OTeF5)2·1.5NgF2 also have gauche-conformations and are linked through bridging NgF2 molecules, also resulting in chain structures. These complexes represent the only examples of coordination compounds where NgF2 coordinates to mercury in a neutral covalent compound and the only example of mercury coordinated to KrF2. Moreover, the Hg(OTeF5)2·1.5KrF2 complex is the only KrF2 complex known to contain a bridging KrF2 ligand. Energy-minimized gas-phase geometries and vibrational frequencies for the model compounds, [Hg(OTeF5)2]3 and [Hg(OTeF5)2]3·2NgF2, were obtained and provide good approximations of the local environments of Hg(OTeF5)2 and NgF2 in the crystal structures of Hg(OTeF5)2 and Hg(OTeF5)2·1.5NgF2. Assignments of the Raman spectra of Hg(OTeF5)2 and Hg(OTeF5)2·1.5NgF2 are based on the calculated vibrational frequencies of the model compounds. Natural bond orbital analyses provided the associated bond orders, valencies, and natural population analysis charges.

Syntheses, Structures, and Bonding of NgF2⋅CrOF4, NgF2⋅2CrOF4(Ng=Kr, Xe), and (CrOF4)∞

“…[30,31] The NgF 2 ·2CrOF 4 adduct consists of aN gF 2 molecule that is symmetrically coordinated to two CrOF 4 molecules through fluorine bridges. [37] Its xenon analogue, [Hg(OTeF 5 ) 2 ]·1.5XeF 2 ,h as also been characterized [XeÀF b ; 1.981(4), 1.991(4), 2.012(4) ] [37] in addition to ac onsiderable number of examples in which XeF 2 molecules bridge two metal centers. [37] Its xenon analogue, [Hg(OTeF 5 ) 2 ]·1.5XeF 2 ,h as also been characterized [XeÀF b ; 1.981(4), 1.991(4), 2.012(4) ] [37] in addition to ac onsiderable number of examples in which XeF 2 molecules bridge two metal centers.…”

Thiazyl Trifluoride (NSF3) Adducts and Imidodifluorosulfate (F2OSN-) Derivatives of Hg(OTeF5)2

“…XXXX, XXX, XXX−XXX coordinated to two NSF 3 molecules, which are positioned above and below the (HgO μ ) 3 ring, whereas the Hg (2) atom is coordinated to one terminal F 5 TeO-group. The Hg (2) −O (6) bond length of the terminal F 5 TeO-group (2.051(9) Å) is comparable to those of Hg(OTeF 5 ) 2 (2.016(6) Å), 34 (Table 4) are comparable to a The atom labeling scheme corresponds to that used in Figures 5 and S1. See Table S5 for a complete list of geometrical parameters.…”

“…34 The Lewis acidity of Hg(OTeF 5 ) 2 was recently demonstrated by the syntheses of the noble-gas difluoride adducts, Hg(OTeF 5 ) 2 ·1.5NgF 2 (Ng = Kr or Xe) 34 and a series of mercury(II) pentafluoro-oxotellurate-(VI) anions. 35 The bulky, highly electronegative F 5 TeO-(teflate) group is terminally bonded in the majority of its compounds.…”

“…The Hg (2) 34 The Hg (2) (OTeF 5 ) 2 unit also interacts with two bridging F 5 TeO-groups (Hg (2) −O, 2.506(7), 2.501(7) Å). The Hg (3) atom is coordinated to two NSF 3 molecules (Hg (3) Table S8).…”

“…35 Bands appearing between 472 and 514 cm −1 are assigned to [ν(Hg−O) + ν(Te− O)]-type stretching modes by comparison with Hg(OTeF 5 ) 2 (472−511 cm −1 ) and its derivatives. 34,35 The bands lying between 541 and 579 cm −1 in the Raman spectra of 2 and 3 are assigned to δ s (SF 3 ) NSF 3 by comparison with NSF 3 (526 and 530 cm −1 ) 8 and [F 3 SNXeF] + (556−570 cm −1 ). 15 The bands between 535 and 575 cm −1 in the spectra of 4 and 5 may also be assigned to δ s (NSF 2 ) NSOF 2 as observed in [Hg(NSOF 2 ) 4 ] 2− (555 cm −1 ).…”