Chromium(VI) Oxyfluoride Dianions, [Cr O F ] and [CrO F ] ; Syntheses and Structures of [XeF ] [Cr O F ], [XeF ] [Cr O F ] ⋅ nX (X=HF, n=4; X=XeOF , n=2), and [XeF ][Xe F ][CrO F ].

The fluorobasic character of the strong oxidative fluorinator, XeF , and the oxidative resistance of the [XeF ] and [Xe F ] cations have been exploited for the syntheses of several novel Cr(VI) dianion salts. The reactions of XeF and CrO F in anhydrous HF and by direct fusion of the reactants in melts have yielded the first dinuclear Cr(VI) oxyfluoro-dianion salts, [XeF ] [Cr O F ], [XeF ] [Cr O F ] ⋅ 4HF, [XeF ] [Cr O F ] ⋅ 2XeOF , and mononuclear Cr(VI) oxyfluoro-dianion salt, [XeF ][Xe F ][CrO F ]. The salts were structurally characterized by low-temperature (LT) single-crystal X-ray diffraction (SCXRD) and LT Raman spectroscopy.

XeF Coordination Complexes of the [BrO] Cation, [OBr(FXeF)][AsF] ( = 1, 2) and [OBr(FXeF)][SbF]; Their Syntheses and Structural Characterizations.

The syntheses and structural characterizations of the first XeF coordination complexes of the [BrO] cation are described. The reactions of [BrO][PnF] (Pn = As, Sb) with XeF in anhydrous HF solvent yield the salts [OBr(FXeF)][AsF] ( = 1, 2) and [OBr(FXeF)][SbF], which were characterized by low-temperature (LT) Raman spectroscopy and single-crystal X-ray diffraction (SCXRD). The XeF ligands and [PnF] coordinate to the Lewis acidic [BrO] cation through primarily electrostatic Br---F σ-hole bonds that result from coordination of the F atoms into regions of high positive electrostatic potential on the Br(V) atom and have bond trajectories that avoid the stereoactive valence electron lone-pair of Br(V).

Synthesis, Structure, and Bonding of a Xe Transition-Metal Coordination Complex, F XeF - - -WOF.

The coordination complex, F XeF - - -WOF , was synthesized in CFCl solvent by reaction of the weak fluoride-ion donor and strong oxidative fluorinating agent, XeF , with the moderate-strength fluoride-ion acceptor, WOF . The compound is the only transition-metal coordination complex of Xe and was characterized at low temperatures by single-crystal X-ray diffraction and Raman spectroscopy. Xenon tetrafluoride and WOF coordinate trans to the W=O bond through a W- - -F bond.

Noble-Gas Difluoride Complexes of MOF (M=Mo, W); Syntheses, Structures and Bonding of NgF ⋅ MOF and XeF ⋅ 2MOF (Ng=Kr, Xe).

The NgF  ⋅ MOF (Ng=Kr, Xe; M=Mo, W) and XeF  ⋅ 2MOF complexes were synthesized in anhydrous HF (aHF) solvent and melts, respectively. Their single-crystal X-ray diffraction (SCXRD) structures show NgF  ⋅ MOF and XeF  ⋅ 2MOF have F -Ng-F - - -M arrangements, in which the NgF ligands coordinate to MOF through Ng-F - - -M bridges. The XeF ligands of XeF  ⋅ 2MOF also coordinate to F OM-F '- - -M'OF moieties through Xe-F - - -M bridges to form F -Xe-F - - -M(OF )-F '- - -M'OF , where XeF coordinates trans to the M=O bond and F ' coordinates trans to the M'=O bond.

Syntheses and Characterizations of the Mixed Noble-Gas Compounds, [FKr FXe F][AsF ]⋅0.5 Kr F ⋅2 HF, ([Kr F ][AsF ]) ⋅Xe F , and Xe F ⋅Kr F.

Reaction of [XeF][AsF ] with excess KrF at -78 °C in anhydrous HF (aHF) solvent has yielded the first mixed Kr /Xe noble-gas compound, [FKrFXeF][AsF ] ⋅0.5 KrF ⋅2 HF, a salt of the [FKrFXeF] cation. The potent oxidative fluorinating properties of Kr fluoride species resulted in oxidation of Xe to Xe in aHF at -60 °C to form the mixed Kr /Xe cocrystals, ([Kr F ][AsF ]) ⋅XeF and XeF ⋅KrF .

Mixed Noble-Gas Compounds of Krypton(II) and Xenon(VI); [F Xe(FKrF)AsF ] and [F Xe(FKrF) AsF ].

The coordination chemistry of KrF has been limited in contrast with that of XeF , which exhibits a far richer coordination chemistry with main-group and transition-metal cations. In the present work, reactions of [XeF ][AsF ] with KrF in anhydrous HF solvent afforded [F Xe(FKrF)AsF ] and [F Xe(FKrF) AsF ], the first mixed krypton/xenon compounds. X-ray crystal structures and Raman spectra show the KrF ligands and [AsF ] anions are F-coordinated to the xenon atoms of the [XeF ] cations.

Group 6 Oxyfluoro-Anion Salts of [XeF ] and [Xe F ] : Syntheses and Structures of [XeF ][M O F ] (M=Mo, W), [Xe F ][M'OF ] (M'=Cr, Mo, W), [XeF ][HF ]⋅CrOF , and [XeF ][WOF ]⋅XeOF.

The reactions of the fluoride-ion donor, XeF , with the fluoride-ion acceptors, M'OF (M'=Cr, Mo, W), yield [XeF ] and [Xe F ] salts of [M'OF ] and [M O F ] (M=Mo, W). Xenon hexafluoride and MOF react in anhydrous hydrogen fluoride (aHF) to give equilibrium mixtures of [Xe F ] , [XeF ] , [(HF) F] , [MOF ] , and [M O F ] from which the title salts were crystallized. The [XeF ][CrOF ] and [Xe F ][CrOF ] salts could not be formed from mixtures of CrOF and XeF in aHF at low temperature (LT) owing to the low fluoride-ion affinity of CrOF , but yielded [XeF ][HF ]⋅CrOF instead.

Chromium Oxide Tetrafluoride and Its Reactions with Xenon Hexafluoride; the [XeF ] and [Xe F ] Salts of the [Cr OF ] , [Cr OF ] , [Cr O F ] , and [Cr F ] Anions.

Molten mixtures of XeF and Cr OF react by means of F elimination to form [XeF ][Xe F ][Cr OF ]⋅2 Cr OF , [XeF ] [Cr F ]⋅2 Cr OF , [Xe F ] [Cr F ], and [XeF ] [Cr O F ], whereas their reactions in anhydrous hydrogen fluoride (aHF) and CFCl /aHF yield [XeF ] [Cr O F ]⋅2 HF and [XeF ] [Cr O F ]⋅2 XeOF . Other than [Xe F ][M OF ] and [XeF ][M O F ] (M=Mo or W), these salts are the only Group 6 oxyfluoro-anions known to stabilize noble-gas cations. Their reaction pathways involve redox transformations that give [XeF ] and/or [Xe F ] salts of the known [Cr OF ] and [Cr F ] anions, and the novel [Cr O F ] anion.

Xenon Trioxide Adducts of O-Donor Ligands; [(CH ) CO] XeO , [(CH ) SO] (XeO ) , (C H NO) (XeO ) , and [(C H ) PO] XeO.

Xenon trioxide (XeO ) forms adducts with triphenylphosphine oxide, dimethylsulfoxide, pyridine-N-oxide, and acetone by coordination of the ligand oxygen atoms to the Xe atom of XeO . The crystalline adducts were characterized by low-temperature, single-crystal X-ray diffraction, and Raman spectroscopy. Unlike solid XeO , which detonates when mechanically or thermally shocked, solid (C H NO) (XeO ) , [(C H ) PO] XeO , and [(CH ) SO] (XeO ) are insensitive to mechanical shock.

Syntheses, Structures, and Bonding of NgF ⋅CrOF , NgF ⋅2CrOF (Ng=Kr, Xe), and (CrOF ).

The noble-gas difluoride adducts, NgF ⋅CrOF and NgF ⋅2CrOF (Ng=Kr and Xe), have been synthesized and structurally characterized at low temperatures by Raman spectroscopy and single-crystal X-ray diffraction. The low fluoride ion affinity of CrOF renders it incapable of inducing fluoride ion transfer from NgF (Ng=Kr and Xe) to form ion-paired salts of the [NgF] cations having either the [CrOF ] or [Cr O F ] anions. The crystal structures show the NgF ⋅CrOF adducts are comprised of F -Ng-F - - -Cr(O)F structural units in which NgF is weakly coordinated to CrOF by means of a fluorine bridge, F , in which Ng-F is elongated relative to the terminal Ng-F bond.

A Stable Crown Ether Complex with a Noble-Gas Compound.

Crown ethers have been known for over 50 years, but no example of a complex between a noble-gas compound and a crown ether or another polydentate ligand had previously been reported. Xenon trioxide is shown to react with 15-crown-5 to form the kinetically stable (CH CH O) XeO adduct, which, in marked contrast with solid XeO , does not detonate when mechanically shocked. The crystal structure shows that the five oxygen atoms of the crown ether are coordinated to the xenon atom of XeO .

Coordination of KrF to a Naked Metal Cation, Mg.

Examples of coordination compounds in which KrF functions as a ligand are very rare. In contrast, XeF provides a rich coordination chemistry with a variety of main-group and transition metal cations. The reactions of Mg(AsF ) and KrF in HF or BrF solvent have afforded [Mg(KrF ) (AsF ) ] and [Mg(KrF ) (AsF ) ]⋅2 BrF , respectively, the first examples of a metal cation ligated by KrF .

Syntheses and Structures of Xenon Trioxide Alkylnitrile Adducts.

The potent oxidizer and highly shock-sensitive binary noble-gas oxide XeO interacts with CH CN and CH CH CN to form O XeNCCH , O Xe(NCCH ) , O XeNCCH CH , and O Xe(NCCH CH ) . Their low-temperature single-crystal X-ray structures show that the xenon atoms are consistently coordinated to three donor atoms, which results in pseudo-octahedral environments around the xenon atoms. The adduct series provides the first examples of a neutral xenon oxide bound to nitrogen bases.

Nature of the Xe(VI)-N Bonds in F6 XeNCCH3 and F6 Xe(NCCH3)2 and the Stereochemical Activity of Their Xenon Valence Electron Lone Pairs.

The recently reported syntheses and X-ray crystal structures of the highly endothermic compounds F6XeNCCH3 and F6Xe(NCCH3)2 ⋅CH3CN provide the first, albeit weakly covalent, Xe(VI)-N bonds. The XeF6 unit of F6 XeNCCH3 possesses distorted octahedral (C3v ) symmetry similar to gas-phase XeF6 , whereas the XeF6 unit of F6 Xe(NCCH3)2 ⋅CH3CN possesses C2v symmetry. Herein, the natural bond orbital (NBO), atoms in molecules (AIM), electron localization function (ELF), and molecular electrostatic potential surface (MEPS) analyses show that the Xe valence electron lone pairs (VELPs) of both compounds are stereochemically active.

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

Reactions of Hg(OTeF5)2 with excess amounts of NSF3 at 0 °C result in the formation of NSF3 adducts having the compositions [Hg(OTeF5)2·N≡SF3]∞ (1), [Hg(OTeF5)2·2N≡SF3]2 (2), and Hg3(OTeF5)6·4N≡SF3 (3). When the reactions are carried out at room temperature, oxygen/fluorine metatheses occur yielding the F2OSN- derivatives [Hg(OTeF5)(N═SOF2)·N≡SF3]∞ (4) and [Hg3(OTeF5)5(N═SOF2)·2N≡SF3]2 (5). The proposed reaction pathway leading to F2OSN- group formation occurs by nucleophilic attack by a F5TeO- group at the sulfur(VI) atom of NSF3, followed by TeF6 elimination.

[XeOXeOXe](2+), the Missing Oxide of Xenon(II); Synthesis, Raman Spectrum, and X-ray Crystal Structure of [XeOXeOXe][μ-F(ReO2F3)2]2.

The [XeOXeOXe](2+) cation provides an unprecedented example of a xenon(II) oxide and a noble-gas oxocation as well as a rare example of a noble-gas dication. The [XeOXeOXe](2+) cation was synthesized as its [μ-F(ReO2F3)2](-) salt by reaction of ReO3F with XeF2 in anhydrous HF at -30 °C. Red-orange [XeOXeOXe][μ-F(ReO2F3)2]2 rapidly decomposes to XeF2, ReO2F3, Xe, and O2 when the solid or its HF solutions are warmed above -20 °C.

Syntheses and Structures of F6 XeNCCH3 and F6 Xe(NCCH3)2.

Acetonitrile and the potent oxidative fluorinating agent XeF6 react at -40 °C in Freon-114 to form the highly energetic, shock-sensitive compounds F6XeNCCH3 (1) and F6Xe(NCCH3)2⋅CH3CN (2⋅CH3CN). Their low-temperature single-crystal X-ray structures show that the adducted XeF6 molecules of these compounds are the most isolated XeF6 moieties thus far encountered in the solid state and also provide the first examples of Xe(VI)-N bonds. The geometry of the XeF6 moiety in 1 is nearly identical to the calculated distorted octahedral (C3v) geometry of gas-phase XeF6.

Lewis acid behavior of SF4 : synthesis, characterization, and computational study of adducts of SF4 with pyridine and pyridine derivatives.

Sulfur tetrafluoride was shown to act as a Lewis acid towards organic nitrogen bases, such as pyridine, 2,6-dimethylpyridine, 4-methylpyridine, and 4-dimethylaminopyridine. The SF4 ⋅NC5 H5 , SF4 ⋅2,6-NC5 H3 (CH3 )2 , SF4 ⋅4-NC5 H4 (CH3 ), and SF4 ⋅4-NC5 H4 N(CH3 )2 adducts can be isolated as solids that are stable below -45 °C. The Lewis acid-base adducts were characterized by low-temperature Raman spectroscopy and the vibrational bands were fully assigned with the aid of density functional theory (DFT) calculations.

Pentafluoro-oxotellurate(VI) anions of mercury(II); syntheses and structures of [Hg(OTeF5)4](2-), [Hg(OTeF5)5](3-), [Hg2(OTeF5)6](2-), [Hg(OTeF5)4](2-)·Hg(OTeF5)2, and [Hg2(OTeF5)7](3-)·Hg(OTeF5)2.

Mercury(II) anions derived from the F5TeO- (teflate) group were synthesized and structurally characterized. The salts, [N(CH2CH3)4]2[Hg(OTeF5)4], [N(CH3)4]3[Hg(OTeF5)5], [N(CH2CH3)4]3[Hg(OTeF5)5], [N(CH3)4]2[Hg2(OTeF5)6], Cs2[Hg(OTeF5)4]·Hg(OTeF5)2, and {Cs3[Hg2(OTeF5)7]·Hg(OTeF5)2}·4SO2ClF, were obtained by reaction of Hg(OTeF5)2 with [M][OTeF5] (M = [N(CH3)4](+), [N(CH2CH3)4](+), Cs(+)) and were characterized by low-temperature single-crystal X-ray diffraction and low-temperature Raman spectroscopy. Unlike in the extensively fluorine-bridged solid-state structures of [HgF3](-) and [HgF4](2-), the less basic and more sterically demanding teflate ligands of the Hg(II) anions show less tendency to bridge.

Xenon(IV)-carbon bond of [C6F5XeF2]+; structural characterization and bonding of [C6F5XeF2][BF4], [C6F5XeF2][BF4]·2HF, and [C6F5XeF2][BF4]·nNCCH3 (n = 1, 2); and the fluorinating properties of [C6F5XeF2][BF4].

The [C6F5XeF2](+) cation is the only example of a Xe(IV)-C bond, which had only been previously characterized as its [BF4](-) salt in solution by multi-NMR spectroscopy. The [BF4](-) salt and its new CH3CN and HF solvates, [C6F5XeF2][BF4]·1.5CH3CN and [C6F5XeF2][BF4]·2HF, have now been synthesized and fully characterized in the solid state by low-temperature, single-crystal X-ray diffraction and Raman spectroscopy.

Noble-gas difluoride complexes of mercury(II): the syntheses and structures of Hg(OTeF5)2·1.5NgF2 (Ng = Xe, Kr) and Hg(OTeF5)2.

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.

Crystal structures and Raman spectra of imidazolium poly[perfluorotitanate(IV)] salts containing the [TiF6]2-, ([Ti2F9]-)∞, and [Ti2F11]3- and the new [Ti4F20]4- and [Ti5F23]3- anions.

Reactions between imidazole (Im, C3H4N2) and TiF4 in anhydrous hydrogen fluoride (aHF) in different molar ratios have yielded [ImH]2[TiF6]·2HF, [ImH]3[Ti2F11], [ImH]4[Ti4F20], [ImH]3[Ti5F23], and [ImH][Ti2F9] upon crystallization. All five structures were characterized by low-temperature single-crystal X-ray diffraction. The single-crystal Raman spectra of [ImH]4[Ti4F20], [ImH]3[Ti5F23], and [ImH][Ti2F9] were also recorded and assigned.

Synthesis and Lewis acid properties of (ReO3F)∞ and the X-ray crystal structures of (HF)2ReO3F·HF and [N(CH3)4]2-[{ReO3(μ-F)}3(μ3-O)]·CH3CN.

A high-yield, high-purity synthesis of (ReO3F)∞ has been achieved by solvolysis of Re2O7 in anhydrous HF (aHF) followed by reaction of the water formed with dissolved F2 at room temperature. The improved synthesis has allowed the Lewis acid and fluoride ion acceptor properties of (ReO3F)∞ to be further investigated. The complex, (HF)2ReO3F·HF, was obtained by dissolution of (ReO3F)∞ in aHF at room temperature and was characterized by vibrational spectroscopy and single-crystal X-ray diffraction at -173 °C.

H(OXeF2)n][AsF6] and [FXe(II)(OXe(IV)F2)n][AsF6] (n = 1, 2): examples of xenon(IV) hydroxide fluoride and oxide fluoride cations and the crystal structures of [F3Xe---FH][Sb2F11] and [H5F4][SbF6]·2[F3Xe---FH][Sb2F11.

The xenon(IV) hydroxide fluoride and oxide fluoride salts, [H(OXeF2)n][AsF6] and [FXe(II)(OXe(IV)F2)n][AsF6] (n = 1, 2), have been synthesized as the natural abundance and the (18)O- and (2)H-enriched salts and structurally characterized by low-temperature Raman spectroscopy. Quantum-chemical calculations have been used to arrive at vibrational assignments. The experimental vibrational frequencies and isotopic shift trends are reproduced by the calculated gas-phase frequencies at several levels of theory.

SF4·N(C2H5)3: the first conclusively characterized SF4 adduct with an organic base.

Sulfur tetrafluoride and triethylamine react at low temperatures to form a 1:1 adduct. The unambiguous characterization of the SF(4)·N(C(2)H(5))(3), which is only stable at low temperature, proves the Lewis acid property of SF(4) towards organic Lewis bases. The S-N bond has a length of 2.