Hydroxylammonium Tetrafluoridooxidovanadate(V) – (NH3OH)[VOF4]

Abstract

Dedicated to the memory of Prof. Dr. Jurij V. Bren~i~. AbstractHydroxylammonium tetrafluoridooxidovanadate(V) has been prepared by reaction of (NH 3 OH)Cl and VOF 3 in anhydrous HF solvent and characterised in the solid state by single-crystal X-ray diffraction and Raman spectroscopy. Colourless (NH 3 OH) [VOF 4 ] crystallises in the monoclinic space group P2 1 /n with a = 7.2349(2) Å, b = 5.0351 (2)

Reactivity of VOF3 with N-Heterocyclic Carbene and Imidazolium Fluoride: Analysis of Ligand–VOF3 Bonding with Evidence of a Minute π Back-Donation of Fluoride

“…The addition of another equivalent of [(L Dipp )H][F] does not lead to the formation of known isolated [VOF 5 ] 2− anion 6 but rather a mixture of [(L Dipp )H][ VOF 4 ] (1) and unreacted starting imidazolium fluoride according to 19 F NMR spectroscopy (Figure S7 in the Supporting Information). Prolonged reaction times do not yield any additional components.…”

“…Samples were loaded into NMR tubes in a glovebox under an argon atmosphere. NMR spectra ( 1 H, 13 C, 19 13 C were referenced to residual signals of deuterated solvent and are reported relative to tetramethylsilane (TMS) as primary reference. 19 F signals were referenced to CFCl 3 in deuterated benzene (C 6 D 6 ) as an external standard, and 51 V signals were referenced according to lock frequency and are given relative to the neat VOCl 3 .…”

“…Yield: 407 mg (94.7%). 1 H NMR (303.0 MHz, 25 °C, CD 3 CN): δ 8.94 (s, 1H, C2−H), 7.88 (s, 2H, CHCH), 7.66 (t, J = 7.6 Hz, 2H, p-ArH), 7.48 (d, J = 7.5 Hz, 4H, m-ArH), 2.42 (sept, J = 6.7 Hz, 4H, CHMe 2 ), 1.27 (d, J = 6.7 Hz, 12H, CH 3 ), 1.20 (d, J = 6.7 Hz, 12H, CH 3 ); 19 F NMR (285.1 MHz, 25 °C, CD 3 CN): δ 129.0 (oct, J = 87.0 Hz); 51 V NMR (79.6 MHz, 25 °C, CD 3 CN): δ −796.9 (quint, J = 87.0 Hz). Elemental analysis calculated for C 27 H 37 N 2 OF 4 V (M w = 532.54 g/ mol): C 60.90, H 7.00, N 5.26%; found: C 61.80, H 7.14, N 5.36%.…”

“…To evaluate the stability of the [VOF 4 ] − anion, the [(L Dipp )H][ VOF 4 ] (1) salt was dissolved in acetonitrile solutions with 10 or 30 equiv of water. Isolation of the products after 16 h experiment and subsequent analysis of their 19 F and 51 V NMR spectra revealed that, in both instances, partial hydrolysis of the [VOF 4 ] − anion does occur. Decomposition of the anion leads to the formation of the [VO 2 F 2 ] − anion (Figures S5 and S6, and Table S1 in the Supporting Information).…”

“…Nevertheless, when the crystal structure of the salt was later determined, the anion was described as a polymeric ribbon of distorted [VOF 4 ] − octahedra connected through fluorine bridges . Further studies of MVOF 4 compounds with small cations (M = Na + , K + , Rb + , Cs + , Tl + , Ag + , NH 3 OH + ) also led to polymeric crystal structures with chains of [VOF 4 ] − anions connected through fluorine bridges. − Studies with double protonated ethylene diamine (en) resulted in the structural characterization of [enH 2 ]­[VOF 4 ­(H 2 O)] 2 with a discrete anion in which vanadium is octahedrally coordinated due to a water molecule located trans to the oxygen atom in [VOF 4 ] − . The same octahedral coordination was reported for [C 4 N 2 ­H 12 ] 3 ­[V 2 O 2 F 8 ]­[VOF 4 ­(H 2 O)] 2 in which a discrete [VOF 4 ­(H 2 O)] − unit is highly distorted as a result of the trans -effect of the VO group on the lengthened V–OH 2 bond …”