supplementary materials


ng5300 scheme

Acta Cryst. (2012). E68, m1371    [ doi:10.1107/S1600536812042584 ]

Sodium pentafluorophenylborate

H. Vitze, H.-W. Lerner and M. Bolte

Abstract top

The crystal structure of the title compound, Na[(C6F5)BH3], is composed of discrete anions and cations. The sodium cations are surrounded by four anions with three short Na...B [2.848 (8), 2.842 (7) and 2.868 (8) Å] and two short Na...F contacts [2.348 (5) and 2.392 (5) Å], forming a three-dimensional network. The anion is the first structural example of a pentafluorophenyl ring carrying a BH3 group.

Comment top

The hydridoborates [(C6F5)BH3]- and [(C6F5)2BH2]- are convenient starting materials for the in situ generation of the boranes (C6F5)BH2 and (C6F5)2BH (Schnurr et al., 2011). In this paper we report the crystal structure of Na[(C6F5)BH3] which was obtained from the reaction mixture of (C6F5)B(OMe)2 and Li[AlH4] by a cation exchange with NaOH (Fig. 1).

The title compound (Fig. 2) is composed of discrete anions and cations. The sodium cations are surrounded by four anions with three short Na···B [Na1···B1 2.848 (8) Å, Na1···B1i 2.842 (7) Å, Na1···B1ii 2.868 (8) Å; symmetry operators: (i) -x + 2, y - 1/2, -z + 1, (ii) -x + 1, y - 1/2, -z + 1] and two short Na···F [Na1···F6ii 2.348 (5) Å, Na1···F2ii 2.392 (5) Å] contacts (Fig. 3).

It is remarkable that this is the first structure with an pentafluorophenyl ring carrying a BH3 group. A search in the Cambridge Crystallographic Database (CSD, Version 5.33 of November 2011, plus three updates (Allen, (2002). Acta Cryst. B58, 380–388) yielded no hit at all for this fragment.

Related literature top

For synthetic background, see: Schnurr et al. (2011). For a description of the Cambridge Structural Database, see: Allen (2002).

Experimental top

In a round bottom flask (C6F5)B(OMe)2 (0.16 g, 0.65 mmol) was dissolved in 10 ml diethyl ether. Under stirring a 1 m solution of Li[AlH4] in diethyl ether (1.2 mmol, 1.1 ml) was added via canula. A brown slurry was obtained which was treated with 3 ml aqueous NaOH (3 mmol) and 15 ml benzene. Insoluble material was removed by filtration from the organic layer. Single crystals of the title compound were obtained of the concentrated benzene solution (5 ml). Yield 20%.

Refinement top

Due to the absence of anomalous scatterers, the absolute structure could not be determined and 414 Friedel pairs were merged. H atoms were located in a difference map, but geometrically positioned and refined using a riding model with fixed individual displacement parameters [U(H) = 1.5 Ueq(B)] and with B—H = 0.98 Å. The BH3 group was allowed to rotate but not to tip.

Computing details top

Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-AREA (Stoe & Cie, 2001); data reduction: X-AREA (Stoe & Cie, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Reaction scheme for obtaining the title compound.
[Figure 2] Fig. 2. Perspective view of the title compound. Displacement ellipsoids are drawn at the 30% probability level.
[Figure 3] Fig. 3. Environment of a sodium cation.
Sodium pentafluorophenylborate top
Crystal data top
Na+·C6H3BF5F(000) = 200
Mr = 203.88Dx = 1.798 Mg m3
Monoclinic, P21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ybCell parameters from 1888 reflections
a = 4.6813 (10) Åθ = 3.7–25.5°
b = 6.1986 (16) ŵ = 0.24 mm1
c = 12.993 (3) ÅT = 173 K
β = 92.995 (17)°Plate, colourless
V = 376.51 (15) Å30.21 × 0.18 × 0.03 mm
Z = 2
Data collection top
STOE IPDS II two-circle-
diffractometer
775 independent reflections
Radiation source: fine-focus sealed tube601 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.116
ω scansθmax = 25.6°, θmin = 3.6°
Absorption correction: multi-scan
(MULABS; Spek, 2009 and Blessing, 1995)
h = 55
Tmin = 0.951, Tmax = 0.993k = 67
2267 measured reflectionsl = 1515
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.058Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.138H-atom parameters constrained
S = 1.01 w = 1/[σ2(Fo2) + (0.0711P)2]
where P = (Fo2 + 2Fc2)/3
775 reflections(Δ/σ)max < 0.001
119 parametersΔρmax = 0.37 e Å3
1 restraintΔρmin = 0.45 e Å3
Crystal data top
Na+·C6H3BF5V = 376.51 (15) Å3
Mr = 203.88Z = 2
Monoclinic, P21Mo Kα radiation
a = 4.6813 (10) ŵ = 0.24 mm1
b = 6.1986 (16) ÅT = 173 K
c = 12.993 (3) Å0.21 × 0.18 × 0.03 mm
β = 92.995 (17)°
Data collection top
STOE IPDS II two-circle-
diffractometer
775 independent reflections
Absorption correction: multi-scan
(MULABS; Spek, 2009 and Blessing, 1995)
601 reflections with I > 2σ(I)
Tmin = 0.951, Tmax = 0.993Rint = 0.116
2267 measured reflectionsθmax = 25.6°
Refinement top
R[F2 > 2σ(F2)] = 0.058H-atom parameters constrained
wR(F2) = 0.138Δρmax = 0.37 e Å3
S = 1.01Δρmin = 0.45 e Å3
775 reflectionsAbsolute structure: ?
119 parametersFlack parameter: ?
1 restraintRogers parameter: ?
Special details top

Experimental. ;

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Na10.8015 (5)0.5576 (5)0.5911 (2)0.0289 (6)
B10.7013 (14)0.7940 (13)0.4048 (5)0.0245 (15)
H1A0.69280.94770.38730.037*
H1B0.89480.75730.43160.037*
H1C0.56430.76280.45730.037*
C10.6218 (11)0.6519 (12)0.3025 (5)0.0228 (13)
C20.7487 (11)0.4581 (11)0.2778 (5)0.0258 (14)
C30.6739 (13)0.3361 (12)0.1908 (5)0.0297 (15)
C40.4582 (12)0.4078 (14)0.1233 (5)0.0325 (16)
C50.3237 (12)0.6030 (13)0.1438 (5)0.0316 (18)
C60.4083 (12)0.7149 (12)0.2310 (5)0.0275 (15)
F20.9668 (7)0.3764 (7)0.3429 (3)0.0351 (10)
F30.8099 (8)0.1482 (7)0.1730 (3)0.0420 (11)
F40.3794 (9)0.2917 (10)0.0395 (3)0.0495 (13)
F50.1147 (7)0.6743 (8)0.0784 (3)0.0426 (12)
F60.2667 (7)0.9043 (7)0.2468 (3)0.0351 (10)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Na10.0223 (10)0.0281 (14)0.0361 (14)0.0006 (11)0.0003 (9)0.0047 (13)
B10.020 (3)0.028 (4)0.026 (3)0.002 (3)0.000 (3)0.002 (4)
C10.015 (2)0.025 (3)0.028 (3)0.005 (2)0.001 (2)0.004 (3)
C20.017 (2)0.028 (3)0.032 (4)0.003 (3)0.005 (2)0.007 (3)
C30.028 (3)0.025 (4)0.037 (4)0.001 (3)0.008 (3)0.006 (3)
C40.023 (3)0.044 (4)0.029 (3)0.002 (3)0.002 (3)0.006 (3)
C50.018 (2)0.047 (5)0.028 (4)0.001 (3)0.002 (2)0.003 (3)
C60.018 (3)0.039 (4)0.027 (3)0.007 (3)0.007 (2)0.007 (3)
F20.0276 (18)0.031 (2)0.045 (2)0.0079 (18)0.0124 (16)0.003 (2)
F30.040 (2)0.033 (2)0.052 (3)0.012 (2)0.0000 (18)0.009 (2)
F40.039 (2)0.066 (3)0.043 (3)0.006 (2)0.0056 (18)0.022 (3)
F50.0262 (17)0.068 (3)0.033 (2)0.015 (2)0.0083 (15)0.005 (2)
F60.0262 (17)0.044 (3)0.035 (2)0.0156 (18)0.0050 (15)0.002 (2)
Geometric parameters (Å, º) top
Na1—F6i2.348 (5)C2—C31.389 (10)
Na1—F2ii2.392 (5)C3—F31.353 (9)
Na1—B1iii2.842 (7)C3—C41.376 (10)
Na1—B1i2.868 (8)C4—F41.342 (9)
B1—C11.621 (10)C4—C51.396 (11)
B1—H1A0.9800C5—F51.337 (7)
B1—H1B0.9800C5—C61.370 (10)
B1—H1C0.9800C6—F61.369 (8)
C1—C61.385 (9)F2—Na1iii2.392 (5)
C1—C21.385 (10)F6—Na1iv2.348 (5)
C2—F21.387 (7)
F6i—Na1—F2ii95.35 (17)F2—C2—C1119.1 (6)
F6i—Na1—B1iii84.3 (2)C3—C2—C1124.6 (6)
F2ii—Na1—B1iii96.5 (2)F3—C3—C4120.3 (7)
F6i—Na1—B1i66.57 (18)F3—C3—C2120.5 (6)
F2ii—Na1—B1i145.2 (2)C4—C3—C2119.2 (6)
B1iii—Na1—B1i110.1 (3)F4—C4—C3120.4 (7)
C1—B1—H1A109.5F4—C4—C5120.8 (6)
C1—B1—H1B109.5C3—C4—C5118.8 (6)
H1A—B1—H1B109.5F5—C5—C6121.9 (7)
C1—B1—H1C109.5F5—C5—C4119.2 (6)
H1A—B1—H1C109.5C6—C5—C4118.9 (6)
H1B—B1—H1C109.5F6—C6—C5115.9 (6)
C6—C1—C2113.1 (6)F6—C6—C1118.6 (6)
C6—C1—B1121.6 (6)C5—C6—C1125.4 (6)
C2—C1—B1125.3 (6)C2—F2—Na1iii145.7 (4)
F2—C2—C3116.3 (6)C6—F6—Na1iv124.9 (4)
C6—C1—C2—F2179.8 (5)F4—C4—C5—C6179.2 (6)
B1—C1—C2—F21.5 (8)C3—C4—C5—C60.9 (9)
C6—C1—C2—C30.1 (8)F5—C5—C6—F60.3 (9)
B1—C1—C2—C3178.6 (6)C4—C5—C6—F6179.6 (6)
F2—C2—C3—F30.2 (9)F5—C5—C6—C1179.8 (6)
C1—C2—C3—F3179.9 (6)C4—C5—C6—C10.5 (9)
F2—C2—C3—C4179.7 (6)C2—C1—C6—F6179.9 (5)
C1—C2—C3—C40.4 (9)B1—C1—C6—F61.4 (8)
F3—C3—C4—F40.4 (10)C2—C1—C6—C50.0 (9)
C2—C3—C4—F4179.2 (6)B1—C1—C6—C5178.7 (6)
F3—C3—C4—C5179.6 (6)C3—C2—F2—Na1iii30.8 (9)
C2—C3—C4—C50.9 (9)C1—C2—F2—Na1iii149.3 (5)
F4—C4—C5—F50.2 (9)C5—C6—F6—Na1iv151.8 (4)
C3—C4—C5—F5179.7 (6)C1—C6—F6—Na1iv28.2 (7)
Symmetry codes: (i) x+1, y1/2, z+1; (ii) x+2, y+1/2, z+1; (iii) x+2, y1/2, z+1; (iv) x+1, y+1/2, z+1.
references
References top

Allen, F. H. (2002). Acta Cryst. B58, 380–388.

Blessing, R. H. (1995). Acta Cryst. A51, 33–38.

Schnurr, A., Samigullin, K., Breunig, J. M., Bolte, M., Lerner, H.-W. & Wagner, M. (2011). Organometallics, 30, 2838–2843.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Spek, A. L. (2009). Acta Cryst. D65, 148–155.

Stoe & Cie (2001). X-AREA. Stoe & Cie, Darmstadt, Germany.