research communications
5]− salt: (1,10-phen-H)[WOF5] (1,10-phen = 1,10-phenanthroline)
of an ordered [WOFaCanadian Centre for Research in Advanced Fluorine Technologies, Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, Canada, T1K 3M4
*Correspondence e-mail: michael.gerken@uleth.ca
Crystals of 1,10-phenanthrolinium pentafluoridooxidotungstate(VI), (1,10-phen-H)[WOF5] (1,10-phen = 1,10-phenanthroline, C12H8N2), were obtained upon hydrolysis of WF6(1,10-phen) in CH3CN at 193 K. The (1,10-phen-H)[WOF5] salt contains a rare example of a [WOF5]− anion in which the oxygen and fluorine atoms are ordered. This ordering was verified by bond-valence determinations and structural comparisons with [Xe2F11][WOF5] and Lewis acid-base adducts of WOF4 with main-group donor ligands. The crystal packing is controlled by N—H⋯F hydrogen bonding that is directed exclusively to the axial F atom as a result of its increased basicity caused by the trans influence of the oxido ligand.
Keywords: tungsten; fluoride; oxide; crystal structure; O/F ordered anion.
CCDC reference: 2016898
1. Chemical context
The 4 (Edwards & Jones, 1968), as well as those of various fluorido-oxidotungstates(VI) of the form [WOnF6–n]n− (n = 1–3), are characterized by extensive disorder between the oxido and fluorido ligands (Voit et al., 2006). Such disorder complications originally led to the incorrect assumption that WOF4 existed as an oxygen-bridged species. This was later disproved by vibrational spectroscopic studies of WOF4 that revealed exclusively terminal W=O bonds (Bennett et al., 1972; Asprey et al., 1972). In [WOnF6–n]n− anions, the nature of the O/F disorder can be controlled by the properties of the counter-cations. For example, Na[WO2F4] is ordered (Vlasse et al., 1982; Chaminade et al., 1986), whereas Rb[WO2F4] (Udovenko & Laptash, 2008a) and Cs[WO2F4] (Srivastava et al., 1992) are statically disordered, and [NH4]2[WO2F4] exhibits simultaneous static and dynamic disorder, both of which are quenched below 201 K to reveal an ordered structure (Udovenko & Laptash, 2008b). In addition, the double salt, [HNC6H6OH]2[Cu(NC5H5)4][WO2F4]2, exhibits ordered [WO2F4]2− anions at 153 K as a result of H⋯F and Cu⋯O secondary-bonding interactions (Welk et al., 2001). An ordered [WO3F3]3− fragment was identified within Pb5W3O9F10 (Abrahams et al., 1987) and, despite extensive dynamic disorder within [NH4]3[WO3F3] (Voit et al., 2006), the stereochemistry could be resolved from the observed displacement of the tungsten atoms from their octahedral symmetry centres (Udovenko & Laptash, 2008a). In all cases, mutual cis arrangements of the oxido ligands are preferred (i.e., cis-[WO2F4]2− and fac-[WO3F3]3−). A trans influence from the oxido ligands results in increased electron density on the effected fluorido ligands, and it is these fluorido ligands that participate in fluorine bridging within multinuclear systems, such as in WOF4 and in various [W2O2F9]− salts with different counterions {[H3O]+(Hoskins et al., 1987); [WF4(2,2′-bipy)2]2+(Arnaudet et al., 1992); [Os3(CO)12H]+ (Crossman et al., 1996); [XeF5]+(Bortolus et al., 2020); Li–Cs+ (Stene et al., 2020)}, and in [W2O4F6]2− (Wollert et al., 1991).
of tetrameric, fluorine-bridged WOFCrystallographically characterized [WOF5]− salts with a range of counterions {[As(C6H5)4]+ (Massa et al., 1982); [Cs(15-crown-5)2]+ (Nuszhär et al., 1992); Ag2+ (Mazej et al., 2017); [WF4(1,2-{P(CH3)2}2C6H4)]2+ (Levason et al., 2018)} have exhibited some degree of O/F disorder in the anion, obfuscating the W=O and W—F bond lengths. Recently, however, [Xe2F11][WOF5] and [XeF5][WOF5]·XeOF4 were reported to contain [WOF5]− anions that are ordered as a consequence of multiple Xe⋯F—W interactions (Bortolus et al., 2020). Herein, we report a new ordered [WOF5]− salt in the form of (1,10-phen-H)[WOF5] (Fig. 1), obtained during an attempted crystallization of WF6(1,10-phen) (Turnbull et al., 2019a).
2. Structural commentary
The W=O bond length in (1,10-phen-H)[WOF5] [1.698 (2) Å] is indistinguishable from those in [Xe2F11][WOF5] [1.698 (3) Å; Bortolus et al., 2020), WOF4{OP(C6H5)3} [1.682 (5) Å; Levason et al., 2016] and WOF4(NC5H5) [1.690 (3) Å; Turnbull et al., 2019b]. The W—Feq bond lengths [1.8677 (15)–1.8809 (15) Å] are also insignificantly different from those in WOF4{OP(C6H5)3} [1.857 (3)–1.871 (3) Å; Levason et al., 2016] and WOF4(NC5H5) [1.859 (3)–1.868 (3) Å; Turnbull et al., 2019b]. The W—Feq bonds in [Xe2F11][WOF5] (Bortolus et al., 2020) are also of similar lengths to those in the title compound, although one terminal W—Feq bond [1.848 (2) Å] is significantly shorter in the [Xe2F11]+ salt, and one bridging bond significantly longer [1.900 (2) Å].
The W—Fax bond length of (1,10-phen-H)[WOF5] [2.0048 (15) Å] is slightly shorter than those in [Xe2F11][WOF5] [2.047 (2) Å; Bortolus et al., 2020] and [C5H5NH][W(NC6F5)F5] [2.0212 (13) Å; Turnbull et al., 2017]. In the latter compound, the N1—H1⋯F1 interaction resulted in significant elongation of the W—Fax bond with respect to that observed in [N(CH3)4][W(NC6F5)F5] [1.973 (3) Å; Turnbull et al., 2017]. Gas-phase geometry optimizations of the [Xe2F11][WOF5] and free [WOF5]− corroborated a significant elongation of the W—Fax 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).
The individual bond valences of the [WOF5]− anion in (1,10-phen-H)[WOF5] (Table 1) reveal that the W=O bond (ν = 1.81) is approximately double the strength of the W—Feq bonds (ν = 0.87–0.90), indicating complete O/F ordering; in a disordered anion, the W=O bond valence is artificially decreased due to averaging with the W—F single bonds. The F1 atom possesses a valence sum significantly less than unity (V = 0.81) because of the trans influence of the oxido ligand and N1—H1⋯F1 hydrogen-bonding interaction substantially polarizing that bond.
3. Supramolecular features
Besides the N1—H1⋯F1 hydrogen-bonding interactions, there also exist weak intermolecular C5⋯O [3.163 (3) Å] and C3⋯C10 [3.204 (4) Å] interactions that result in the formation of columns of cations and anions running parallel to the a axis (Fig. 2) in the packed crystal. The crystal packing, however, appears to be dominated by the N1—H1⋯F1 hydrogen bonds (Table 2) and other intermolecular interactions, such as π–π stacking interactions between cations, are absent.
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4. Synthesis and crystallization
In the dry box, a 1/4"-o.d. FEP reactor, equipped with a 316-stainless-steel valve and pre-passivated with F2 (100%, Linde Gas), was charged with WF6(1,10-phen) (ca 0.01 g), prepared as described previously (Turnbull et al., 2019a). Acetonitrile (ca 0.1 mL), dried as previously described (Winfield, 1984), was distilled into the reactor through a glass vacuum line equipped with grease-free PTFE stopcocks (J. Young). The reactor was heated to 353 K in a hot-water bath and allowed to cool to ambient temperature over 16 h. The reactor was then cooled rapidly to 233 K and the solvent was removed under dynamic vacuum at that temperature, resulting in the formation of colourless needles of (1,10-phen-H)[WOF5], together with an off-white microcrystalline material that was not further characterized, but is presumed to contain WF6(1,10-phen) and (1,10-phen-H)[WOF5].
The reactor was cut open and the crystals transferred onto an aluminium trough cooled to 193 K under a constant stream of liquid-N2-cooled, dry N2. The selected crystal was affixed to a Nylon cryo-loop submerged in perfluorinated polyether oil (Fomblin Z-25) and quickly transferred to the goniometer to minimize exposure to air.
5. details
Crystallographic data collection and . All the hydrogen atoms were located in difference Fourier maps and were refined using a riding model, with the exception of H1, the position of which was refined freely (Table 2).
parameters are summarized in Table 3
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Supporting information
CCDC reference: 2016898
https://doi.org/10.1107/S2056989020009767/cq2038sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989020009767/cq2038Isup2.hkl
Data collection: CrysAlis PRO 1.171.38.43 (Rigaku OD, 2015); cell
CrysAlis PRO (Rigaku OD, 2015); data reduction: CrysAlis PRO 1.171.38.43 (Rigaku OD, 2015); program(s) used to solve structure: ShelXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL (Sheldrick, 2015b); molecular graphics: XP (Sheldrick, 2008); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009) and publCIF (Westrip, 2010).(C12H9N2)[WOF5] | F(000) = 888 |
Mr = 476.06 | Dx = 2.489 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 7.1664 (2) Å | Cell parameters from 8493 reflections |
b = 15.5088 (4) Å | θ = 3.6–31.4° |
c = 11.6516 (4) Å | µ = 9.15 mm−1 |
β = 101.202 (3)° | T = 112 K |
V = 1270.31 (7) Å3 | Needle, clear colourless |
Z = 4 | 0.27 × 0.12 × 0.06 mm |
Rigaku SuperNova, Dual source (Mo and Cu), Pilatus 200/300K diffractometer | 2908 independent reflections |
Radiation source: micro-focus sealed X-ray tube, SuperNova (Mo) X-ray Source | 2652 reflections with I > 2σ(I) |
Mirror monochromator | Rint = 0.033 |
ω scans | θmax = 27.5°, θmin = 3.4° |
Absorption correction: analytical [Numeric absorption correction using a multifaceted crystal model based on expressions derived by Clark & Reid (1995) implemented in CrysAlisPro (Rigaku OD, 2015). Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK] | h = −9→9 |
Tmin = 0.447, Tmax = 0.645 | k = −19→20 |
15835 measured reflections | l = −15→13 |
Refinement on F2 | Primary atom site location: dual |
Least-squares matrix: full | Hydrogen site location: mixed |
R[F2 > 2σ(F2)] = 0.016 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.038 | w = 1/[σ2(Fo2) + (0.0179P)2 + 0.7231P] where P = (Fo2 + 2Fc2)/3 |
S = 1.06 | (Δ/σ)max = 0.002 |
2908 reflections | Δρmax = 0.97 e Å−3 |
194 parameters | Δρmin = −0.83 e Å−3 |
0 restraints |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
x | y | z | Uiso*/Ueq | ||
W1 | 0.45262 (2) | 0.57004 (2) | 0.26707 (2) | 0.01171 (4) | |
F1 | 0.4234 (2) | 0.44319 (10) | 0.29168 (15) | 0.0209 (3) | |
F2 | 0.4618 (2) | 0.57848 (10) | 0.42837 (14) | 0.0226 (4) | |
F3 | 0.7145 (2) | 0.54615 (11) | 0.29703 (15) | 0.0222 (3) | |
F4 | 0.4359 (2) | 0.53785 (11) | 0.11094 (13) | 0.0233 (3) | |
F5 | 0.1857 (2) | 0.56900 (10) | 0.24578 (15) | 0.0202 (3) | |
O1 | 0.4729 (3) | 0.67755 (13) | 0.24458 (18) | 0.0242 (4) | |
N1 | 0.1998 (3) | 0.35275 (14) | 0.41042 (18) | 0.0134 (4) | |
H1 | 0.286 (4) | 0.3659 (19) | 0.368 (2) | 0.014 (7)* | |
N2 | 0.4933 (3) | 0.24312 (14) | 0.39891 (19) | 0.0154 (4) | |
C1 | 0.0520 (4) | 0.40604 (17) | 0.4040 (2) | 0.0172 (5) | |
H1A | 0.041718 | 0.455156 | 0.354409 | 0.021* | |
C2 | −0.0870 (4) | 0.39002 (18) | 0.4694 (2) | 0.0198 (6) | |
H2 | −0.195569 | 0.426242 | 0.462155 | 0.024* | |
C3 | −0.0649 (4) | 0.32076 (17) | 0.5449 (2) | 0.0170 (5) | |
H3 | −0.156152 | 0.310602 | 0.592588 | 0.020* | |
C4 | 0.0917 (4) | 0.26498 (17) | 0.5518 (2) | 0.0151 (5) | |
C5 | 0.2231 (3) | 0.28172 (16) | 0.4800 (2) | 0.0129 (5) | |
C6 | 0.3802 (3) | 0.22474 (16) | 0.4765 (2) | 0.0133 (5) | |
C7 | 0.4049 (3) | 0.15380 (17) | 0.5530 (2) | 0.0153 (5) | |
C8 | 0.5628 (4) | 0.10033 (18) | 0.5500 (2) | 0.0189 (5) | |
H8 | 0.588937 | 0.052531 | 0.601602 | 0.023* | |
C9 | 0.6790 (4) | 0.11795 (18) | 0.4715 (2) | 0.0204 (6) | |
H9 | 0.785780 | 0.082457 | 0.467828 | 0.024* | |
C10 | 0.6365 (4) | 0.18924 (17) | 0.3973 (2) | 0.0190 (5) | |
H10 | 0.715470 | 0.199719 | 0.342053 | 0.023* | |
C11 | 0.1198 (4) | 0.19063 (17) | 0.6274 (2) | 0.0181 (5) | |
H11 | 0.032761 | 0.178632 | 0.677319 | 0.022* | |
C12 | 0.2702 (4) | 0.13793 (18) | 0.6272 (2) | 0.0187 (5) | |
H12 | 0.287124 | 0.089145 | 0.677491 | 0.022* |
U11 | U22 | U33 | U12 | U13 | U23 | |
W1 | 0.01223 (6) | 0.01049 (6) | 0.01259 (6) | −0.00060 (3) | 0.00287 (4) | 0.00057 (4) |
F1 | 0.0272 (8) | 0.0131 (8) | 0.0256 (8) | −0.0023 (6) | 0.0129 (7) | −0.0004 (6) |
F2 | 0.0277 (9) | 0.0254 (9) | 0.0147 (8) | −0.0001 (7) | 0.0044 (7) | −0.0030 (6) |
F3 | 0.0153 (8) | 0.0213 (8) | 0.0298 (9) | 0.0018 (6) | 0.0037 (7) | 0.0017 (7) |
F4 | 0.0282 (9) | 0.0284 (9) | 0.0145 (7) | −0.0049 (7) | 0.0071 (6) | −0.0014 (7) |
F5 | 0.0121 (7) | 0.0233 (9) | 0.0249 (8) | 0.0003 (6) | 0.0027 (6) | −0.0025 (6) |
O1 | 0.0249 (10) | 0.0152 (10) | 0.0320 (11) | −0.0003 (8) | 0.0043 (9) | 0.0021 (8) |
N1 | 0.0137 (10) | 0.0133 (10) | 0.0140 (10) | −0.0023 (8) | 0.0051 (9) | −0.0005 (8) |
N2 | 0.0162 (10) | 0.0131 (11) | 0.0179 (11) | −0.0016 (8) | 0.0058 (9) | 0.0000 (9) |
C1 | 0.0209 (13) | 0.0119 (12) | 0.0185 (13) | 0.0018 (10) | 0.0029 (11) | 0.0012 (10) |
C2 | 0.0179 (13) | 0.0183 (14) | 0.0238 (14) | 0.0031 (11) | 0.0056 (11) | −0.0047 (11) |
C3 | 0.0167 (12) | 0.0166 (12) | 0.0191 (13) | −0.0019 (10) | 0.0065 (10) | −0.0060 (10) |
C4 | 0.0151 (12) | 0.0154 (13) | 0.0143 (12) | −0.0044 (10) | 0.0017 (10) | −0.0038 (10) |
C5 | 0.0131 (11) | 0.0107 (12) | 0.0142 (11) | −0.0015 (9) | 0.0007 (9) | −0.0036 (10) |
C6 | 0.0127 (11) | 0.0126 (12) | 0.0143 (11) | −0.0022 (9) | 0.0018 (9) | −0.0027 (9) |
C7 | 0.0158 (12) | 0.0133 (12) | 0.0151 (12) | −0.0025 (10) | −0.0011 (10) | −0.0013 (10) |
C8 | 0.0210 (13) | 0.0139 (12) | 0.0189 (13) | 0.0024 (11) | −0.0035 (11) | 0.0010 (11) |
C9 | 0.0185 (13) | 0.0168 (14) | 0.0250 (14) | 0.0034 (10) | 0.0023 (11) | −0.0042 (11) |
C10 | 0.0152 (12) | 0.0200 (14) | 0.0231 (13) | −0.0010 (10) | 0.0072 (11) | −0.0036 (11) |
C11 | 0.0220 (13) | 0.0174 (13) | 0.0167 (12) | −0.0040 (10) | 0.0083 (11) | −0.0001 (10) |
C12 | 0.0232 (13) | 0.0176 (13) | 0.0143 (12) | −0.0047 (11) | 0.0008 (10) | 0.0018 (10) |
W1—F1 | 2.0048 (15) | C3—C4 | 1.407 (4) |
W1—F2 | 1.8724 (16) | C4—C5 | 1.400 (4) |
W1—F3 | 1.8779 (15) | C4—C11 | 1.441 (4) |
W1—F4 | 1.8677 (15) | C5—C6 | 1.438 (4) |
W1—F5 | 1.8809 (15) | C6—C7 | 1.405 (4) |
W1—O1 | 1.698 (2) | C7—C8 | 1.409 (4) |
N1—H1 | 0.89 (3) | C7—C12 | 1.437 (4) |
N1—C1 | 1.334 (3) | C8—H8 | 0.9500 |
N1—C5 | 1.359 (3) | C8—C9 | 1.379 (4) |
N2—C6 | 1.357 (3) | C9—H9 | 0.9500 |
N2—C10 | 1.326 (3) | C9—C10 | 1.400 (4) |
C1—H1A | 0.9500 | C10—H10 | 0.9500 |
C1—C2 | 1.389 (4) | C11—H11 | 0.9500 |
C2—H2 | 0.9500 | C11—C12 | 1.353 (4) |
C2—C3 | 1.378 (4) | C12—H12 | 0.9500 |
C3—H3 | 0.9500 | ||
F2—W1—F1 | 84.80 (7) | C3—C4—C11 | 122.8 (2) |
F2—W1—F3 | 89.33 (7) | C5—C4—C3 | 118.3 (2) |
F2—W1—F5 | 88.24 (7) | C5—C4—C11 | 118.9 (2) |
F3—W1—F1 | 84.73 (7) | N1—C5—C4 | 119.2 (2) |
F3—W1—F5 | 167.69 (7) | N1—C5—C6 | 119.2 (2) |
F4—W1—F1 | 83.59 (7) | C4—C5—C6 | 121.6 (2) |
F4—W1—F2 | 168.37 (7) | N2—C6—C5 | 117.5 (2) |
F4—W1—F3 | 90.06 (7) | N2—C6—C7 | 124.7 (2) |
F4—W1—F5 | 89.89 (7) | C7—C6—C5 | 117.7 (2) |
F5—W1—F1 | 83.04 (7) | C6—C7—C8 | 116.6 (2) |
O1—W1—F1 | 178.86 (8) | C6—C7—C12 | 120.0 (2) |
O1—W1—F2 | 95.67 (8) | C8—C7—C12 | 123.5 (2) |
O1—W1—F3 | 96.31 (8) | C7—C8—H8 | 120.3 |
O1—W1—F4 | 95.93 (9) | C9—C8—C7 | 119.5 (2) |
O1—W1—F5 | 95.94 (8) | C9—C8—H8 | 120.3 |
C1—N1—H1 | 117.1 (19) | C8—C9—H9 | 120.7 |
C1—N1—C5 | 122.7 (2) | C8—C9—C10 | 118.6 (2) |
C5—N1—H1 | 120.1 (19) | C10—C9—H9 | 120.7 |
C10—N2—C6 | 116.2 (2) | N2—C10—C9 | 124.4 (2) |
N1—C1—H1A | 119.9 | N2—C10—H10 | 117.8 |
N1—C1—C2 | 120.3 (2) | C9—C10—H10 | 117.8 |
C2—C1—H1A | 119.9 | C4—C11—H11 | 120.0 |
C1—C2—H2 | 120.5 | C12—C11—C4 | 119.9 (2) |
C3—C2—C1 | 119.0 (3) | C12—C11—H11 | 120.0 |
C3—C2—H2 | 120.5 | C7—C12—H12 | 119.1 |
C2—C3—H3 | 119.8 | C11—C12—C7 | 121.7 (2) |
C2—C3—C4 | 120.5 (2) | C11—C12—H12 | 119.1 |
C4—C3—H3 | 119.8 |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···F1 | 0.89 (3) | 1.88 (3) | 2.704 (3) | 154 (3) |
νia | Vb | ||
W | 5.98 | ||
W═O | 1.81 | O | 1.88 |
W—F1 | 0.62 | F1 | 0.81 |
W—F2 | 0.89 | F2 | 0.95 |
W—F3 | 0.88 | F3 | 0.94 |
W—F4 | 0.90 | F4 | 0.97 |
W—F5 | 0.87 | F5 | 0.95 |
Notes: (a) Defined as νi = exp[Ro - R/b], where R is the observed bond length (in Å) and Ro and b are empirical parameters (Brown & Altermatt, 1985; Brese & O'Keeffe, 1991; Brown, 2002; Adams et al., 2004). (b) Defined as V = Σ(νi). Only secondary contacts within the sum of the van der Waals' radii (Bondi, 1964) were considered. |
Acknowledgements
We thank the Natural Sciences and Engineering Research Council of Canada (NSERC) for awarding a Discovery grant to MG as well as CGS-M and PGS-D scholarships to DT. In addition, we would like to thank the University of Lethbridge for awarding the SGS Dean's Scholarship and Tuition Award to DT and supporting this work.
Funding information
Funding for this research was provided by: Natural Sciences and Engineering Research Council of Canada (grant No. 261340-2013 to Michael Gerken; scholarship to Douglas Turnbull).
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