Group 6 Oxyfluoro‐Anion Salts of [XeF₅]⁺ and [Xe₂F₁₁]⁺: Syntheses and Structures of [XeF₅][M₂O₂F₉] (M=Mo, W), [Xe₂F₁₁][M′OF₅] (M′=Cr, Mo, W), [XeF₅][HF₂]⋅CrOF₄, and [XeF₅][WOF₅]⋅XeOF₄

Abstract

The reactions of the fluoride‐ion donor, XeF6, with the fluoride‐ion acceptors, M′OF4 (M′=Cr, Mo, W), yield [XeF5]+ and [Xe2F11]+ salts of [M′OF5]− and [M2O2F9]− (M=Mo, W). Xenon hexafluoride and MOF4 react in anhydrous hydrogen fluoride (aHF) to give equilibrium mixtures of [Xe2F11]+, [XeF5]+, [(HF)nF]−, [MOF5]−, and [M2O2F9]− from which the title salts were crystallized. The [XeF5][CrOF5] and [Xe2F11][CrOF5] salts could not be formed from mixtures of CrOF4 and XeF6 in aHF at low temperature (LT) owing to the low fluoride‐ion affinity of CrOF4, but yielded [XeF5][HF2]⋅CrOF4 instead. In contrast, MoOF4 and WOF4 are sufficiently Lewis acidic to abstract F− ion from [(HF)nF]− in aHF to give the [MOF5]− and [M2O2F9]− salts of [XeF5]+ and [Xe2F11]+. To circumvent [(HF)nF]− formation, [Xe2F11][CrOF5] was synthesized at LT in CF2ClCF2Cl solvent. The salts were characterized by LT Raman spectroscopy and LT single‐crystal X‐ray diffraction, which provided the first X‐ray crystal structure of the [CrOF5]− anion and high‐precision geometric parameters for [MOF5]− and [M2O2F9]−. Hydrolysis of [Xe2F11][WOF5] by water contaminant in HF solvent yielded [XeF5][WOF5]⋅XeOF4. Quantum‐chemical calculations were carried out for M′OF4, [M′OF5]−, [M′2O2F9]−, {[Xe2F11][CrOF5]}2, [Xe2F11][MOF5], and {[XeF5][M2O2F9]}2 to obtain their gas‐phase geometries and vibrational frequencies to aid in their vibrational mode assignments and to assess chemical bonding.

Reactions of ClF3 with Main Group and Transition Metal Oxides: Access to Dioxychloronium(V) Fluoridometallates and Oxidofluoridometallates

“…With a central cis ‐bridging [MoOF 5 ] polyhedron, two of the F atoms, F(5) and F(9), are μ‐bridging between the other two Mo atoms, resulting in the [Mo 3 O 3 F 13 ] − anion that can be described with the Niggli formula (Figure 13). Molybdenum oxide tetrafluoride, MoOF 4 , can also form other anions of different nuclearity with fluoride ion donors, such as the mononuclear [MoOF 5 ] − and the dinuclear [Mo 2 O 2 F 9 ] − anion [109,110] …”

Crystal structure of an ordered [WOF5]− salt: (1,10-phen-H)[WOF5] (1,10-phen = 1,10-phenanthroline)

“…The W O bond length in (1,10-phen-H) [ corroborated a significant elongation of the W-F ax bond in the former anion compared to the latter (2.148 vs 1.972 Å , respectively) arising from cation-anion interactions (Bortolus et al, 2020).…”

“…In all cases, mutual cis arrangements of the oxido ligands are preferred (i.e., cis-[WO 2 F 4 ] 2À and fac-[WO 3 F 3 ] 3À ). A trans influence from the oxido ligands results in increased electron density on ISSN 2056-9890 the effected fluorido ligands, and it is these fluorido ligands that participate in fluorine bridging within multinuclear systems, such as in WOF 4 and in various [W 2 O 2 F 9 ] À salts with different counterions {[H 3 O] + (Hoskins et al, 1987); [WF 4 (2,2 0bipy) 2 ] 2+ (Arnaudet et al, 1992); [Os 3 (CO) 12 H] + (Crossman et al, 1996); [XeF 5 ] + (Bortolus et al, 2020); Li-Cs + (Stene et al, 2020)}, and in [W 2 O 4 F 6 ] 2À (Wollert et al, 1991).…”

“…Crystallographically characterized [WOF 5 ] À salts with a range of counterions {[As(C 6 H 5 ) 4 ] + (Massa et al, 1982 (Bortolus et al, 2020). Herein, we report a new ordered [WOF 5 ] À salt in the form of (1,10-phen-H)[WOF 5 ] ( Fig.…”

“…Turnbull et al, 2019b]. The W-F eq bonds in [Xe 2 F 11 ][WOF 5 ](Bortolus et al, 2020) are also of similar lengths to those in the title compound, although one terminal W-F eq bond [1.848(2)Å ] is significantly shorter in the [Xe 2 F 11 ] + salt, and one bridging bond significantly longer [1.900 (2) Å ]. Xe 2 F 11 ][WOF 5 ] [2.047 (2) Å ; Bortolus et al, 2020] and [C 5 H 5 NH][W(NC 6 F 5 )F 5 ] [2.0212 (13) Å ; Turnbull et al, 2017].…”