Xenon(II) Polyfluoridotitanates(IV): Synthesis and Structural Characterization of [Xe₂F₃]⁺ and [XeF]⁺ Salts

Abstract

Thermal reaction between XeF2 and excess TiF4 resulted in the unexpected formation of a highly ionized Xe(II) species. The products [Xe2F3][Ti8F33] and [XeF]2[Ti9F38] represent the first examples of [Xe2F3](+) and [XeF](+) compounds, which differ from known Xe(II) salts containing discrete fluoride anions with pentavalent metalloid/metal centers. A new structural type of 2D polyanion [Ti8F33](-) and the formation and structure of the novel 1D [Ti9F38](2-) are discussed. Both products were characterized by single-crystal X-ray analysis and Raman spectroscopy.

Guanidinium Perfluoridotitanate(IV) Compounds: Structural Determination of an Oligomeric [Ti6F27]3– Anion, and an Example of a Mixed‐Anion Salt Containing Two Different Fluoridotitanate(IV) Anions

“…Since the frequency of the Raman band belonging to the symmetric in‐phase Ti–F t stretching vibration of perfluoridotitanate(IV) anions increases with both an increasing of the TiF 4 content and a decreasing of the anion charge, it is very useful for the identification of various perfluoridotitanate(IV) anions. The frequency ranges from 599 cm –1 in the case of the [TiF 6 ] 2– anion to 807 cm –1 for the TiF 4 itself , , , . The Raman spectra of guanidinium perfluoridotitanates(IV) recorded in the present research also follow this rule.…”

“…In the solid state these units can remain isolated, leading to trivial hexafluoridotitanate(IV) salts, or they can be linked by sharing fluorine ions, yielding larger oligomeric (0‐D geometry) or polymeric (1‐D, 2‐D and 3‐D) anions. So far, there are 18 structurally characterized fluoridotitanate(IV) anions: oligomeric [TiF 6 ] 2– , [Ti 2 F 10 ] 2– ,, [Ti 2 F 11 ] 3– , [Ti 4 F 18 ] 2– , [Ti 4 F 19 ] 3– , [Ti 4 F 20 ] 4– , [Ti 5 F 23 ] 3– , [Ti 8 F 36 ] 4– , [Ti 10 F 45 ] 5– , and polymeric ([TiF 5 ] – ) ∞ , ([Ti 2 F 9 ] – ) ∞ ,, , ([Ti 3 F 13 ] – ) ∞ , ([Ti 4 F 19 ] 3– ) ∞ , ([Ti 6 F 27 ] 3– ) ∞ , ([Ti 7 F 30 ] 2– ) ∞ , ([Ti 9 F 38 ] 2– ) ∞ , and two modifications of the ([Ti 8 F 33 ] – ) ∞ anion , . The geometries of the various anions were determined with X‐ray experiments on single crystals of pure inorganic and/or hybrid compounds.…”

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

“…The polar-covalentb onds of NgF 2 (Ng = Kr or Xe) render both compounds fluoridei on donors towards strong Lewis acid pentafluorides such as AsF 5 ,S bF 5 ,B iF 5 ,N bF 5 ,T aF 5 ,a nd AuF 5 , and are customarily formulated as [NgF] + and [Ng 2 F 3 ] + salts, for example, [XeF][MF 6 ]( M= As, [1] Sb, [1] Bi, [1] Ru, [2] ), [XeF][M 2 F 11 ] (M = Sb, [1,3,4] Bi, [1] Ir, [5] Nb, [6] Ta [6] ), [XeF] 2 [Ti 9 F 38 ], [7] [XeF] [IrSbF 11 ], [5] [Xe 2 F 3 ][MF 6 ]( M = Au, [8] As, [9] Sb [9] ), [Xe 2 F 3 ][Ti 8 F 33 ], [7] [KrF] [MF 6 ] (M = Au, [8,10] Ta, [11] Pt, [12] As, [13] Sb, [11,13] Bi [13] ), [KrF][M 2 F 11 ]( M= Ta, Nb, Sb), [11] [Kr 2 F 3 ][SbF 6 ]·KrF 2 , [13] [Kr 2 F 3 ] 2 [SbF 6 ] 2 ·KrF 2 , [13] 6 ], [13] [KrF][PF 6 ], [13] and [Kr 2 F 3 ][PF 6 ]·nKrF 2 . [13] Althought heir formulationsi mply completef luoridei on transfer from the noble-gas difluoride to the strong Lewis acid pentafluoride, in reality the Lewis acidic [NgF] + cations and their anionse xist as ion pairs in their salts that interact through NgÀF b ---Mb ridges (F b :b ridge fluorine atom).…”

Structural Characterization of a Fluorido‐Amide of Niobium, and Facile CO2 Incorporation Affording a Fluorido‐Carbamate

“…A similar M 4 (µ‐F) 6 core is present in [Ti 4 (µ‐F) 6 F 12 ] 2– , [W 4 (µ‐F) 6 F 12 ] 2–[25] and [Al 4 (µ‐F) 6 F 12 ] 6– . The µ‐F bridges are perfectly symmetric and all the Nb–F[4c], and Nb–NMe 2 distances are as expected for octahedral Nb V complexes. The Nb–F–Nb bridges [156.12(9)–157.34(9)°] are considerably bent due to the tetrahedral structure of the Nb 4 cage, as previously found in the [NbF 2 (µ‐F)(OPh) 2 ] 3 trimer,[6b] whereas the Nb–F–Nb interactions (182.5°) within the tetrameric [NbF 5 ] 4 are almost linear…”

“…The coordination chemistry of transition‐metal fluorides had been neglected for many years for several reasons, including a lack of equipment, limited commercial availability of the precursors and the fact that inorganic fluorides are often intractable polymeric materials Therefore, when complexes were reported, their characterizations were often poor and their properties not investigated in any detail. In spite of this, the interest in high‐valent fluorides of group 4 and 5 metals has progressively grown in the last decade due to their possible applications in organic synthesis, materials chemistry and as possible precursors of innocent, weakly coordinating anions . In particular, a variety of derivatives have been obtained and characterized from the reactions of easily available niobium and tantalum pentafluorides, MF 5 (M = Nb, Ta), with N, O and S donors as well as phosphines and arsines.…”