1-Bromo-2,3,5,6-tetra­fluoro-4-nitro­benzene

Abstract

In the title compound, C₆BrF₄NO₂, the nitro group is twisted by 41.7 (3)° with reference to the arene ring mean plane. The main inter­actions stabilizing the crystal structure include O⋯Br contacts [3.150 (2) and 3.201 (2) Å], while F⋯F inter­actions are minor [2.863 (3)–2.908 (3) Å].

Related literature

For halogen inter­actions in mol­ecular crystal structures, see: Awwadi et al. (2006 ▶); Brammer et al. (2001 ▶); Metrangolo et al. (2008 ▶). For fluorine-involved inter­actions, see: Schwarzer et al. (2010 ▶); Merz & Vasylyeva (2010 ▶); Schwarzer & Weber (2008 ▶); Reichenbächer et al. (2005 ▶). For the synthesis, see: Shtark & Shteingarts (1976 ▶).

Experimental

Crystal data

• C₆BrF₄NO₂

• M _r = 273.98

• Orthorhombic,

• a = 5.6718 (3) Å

• b = 10.9476 (6) Å

• c = 12.2652 (8) Å

• V = 761.58 (8) ų

• Z = 4

• Mo Kα radiation

• μ = 5.44 mm⁻¹

• T = 93 K

• 0.13 × 0.13 × 0.10 mm

Data collection

• Bruker SMART CCD area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2007 ▶) T _min = 0.536, T _max = 0.612

• 4314 measured reflections

• 1550 independent reflections

• 1447 reflections with I > 2σ(I)

• R _int = 0.026

Refinement

• R[F ² > 2σ(F ²)] = 0.023

• wR(F ²) = 0.053

• S = 1.00

• 1550 reflections

• 127 parameters

• 1 restraint

• Δρ_max = 0.32 e Å⁻³

• Δρ_min = −0.53 e Å⁻³

• Absolute structure: Flack (1983) ▶, 636 Friedel pairs

• Flack parameter: 0.026 (10)

Data collection: SMART (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Supplementary material file. DOI: 10.1107/S160053681102201X/su2278Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

supplementary crystallographic information

Comment

Halogen interactions in molecular crystal structures have been the subject of a numer of studies (Awwadi et al., 2006; Brammer et al., 2001; Metrangolo et al., 2008). Fluorine involved interactions in particular have been studied by us and others (Schwarzer et al., 2010; Schwarzer & Weber, 2008; Reichenbächer et al., 2005; Merz & Vasylyeva, 2010). In continuation of that work we report herein on the crystal structure of the title tetrafluoro-benzene compound.

In the title compound (Fig. 1) the plane of the nitro group (O1—N1—O2) shows a twist of 41.68 (28)° with reference to the phenyl ring, owing to repulsive interactions between the ortho-positioned fluorine (F2 and F3) and oxygen atoms. The N—O bond lengths are different (O1—N1: 1.217 (4) Å; O2—N1: 1.234 (3) Å) as a result of different intermolecular interactions.

In the crystal oxygen O1 is involved in two strong intermolecular contacts to bromine Br1 [3.150 (2) and 3.201 (2) Å], giving rise to the formation of a three-dimensional molecular network (Table 1 and Fig. 2). On the other hand, atom O2 forms a weak contact to atom F3 [2.823 (3) Å].

The fluorine···fluorine contacts [2.863 (3) – 2.908 (3) Å] are close to the sum of their van-der-Waals radii hence, they do not contribute significantly to the stabilization of the crystal packing. Moreover, there is no indication for the presence of either π^F···π^F stacking or C—X···π^F interactions (X = O, F, Br). Hence, except for the O···Br interactions, the crystal structure is mostly determined by maximum symmetry and close-packing principles, which is reflected in the low melting point of 321 K.

Experimental

The title compound was synthesized according to the published procedure (Shtark & Shteingarts, 1976). 3-bromo-1,2,4,5-tetrafluorobenzene (2.80 g, 12 mmol) and NO₂BF₄ (6.45 g, 48 mmol) were dissolved in 45 ml of sulfolan and stirred for 2 h at 338 K. After cooling the solution to room temperature, 120 ml water was added and the phases separated. The aqueous layer was extracted with chloroform (3 × 50 ml), dried (Na₂SO₄) and evaporated under reduced pressure. The crude product was purified by water steam distillation to yield 2.66 g (81%) of the title compound. Sublimation techniques yielded single crystals suitable for X-ray crystallography.

Figures

Fig. 1.

A view of the molecular structure of the title molecule, with the atom numbering and showing 50% probability displacement ellipsoids.

Fig. 2.

A partial view, along the a axis, of the crystal packing of the title compound. The O···Br, and potential O···F and F···F contacts are shown as broken lines (see Table 1 for details).

Crystal data

C6BrF4NO2	F(000) = 520
Mr = 273.98	Dx = 2.390 Mg m−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 2319 reflections
a = 5.6718 (3) Å	θ = 3.7–32.8°
b = 10.9476 (6) Å	µ = 5.44 mm−1
c = 12.2652 (8) Å	T = 93 K
V = 761.58 (8) Å3	Needle, colourless
Z = 4	0.13 × 0.13 × 0.10 mm

Data collection

Bruker SMART CCD area-detector diffractometer	1550 independent reflections
Radiation source: fine-focus sealed tube	1447 reflections with I > 2σ(I)
graphite	Rint = 0.026
phi and ω scans	θmax = 27.5°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Bruker, 2007)	h = −7→7
Tmin = 0.536, Tmax = 0.612	k = −14→12
4314 measured reflections	l = −15→15

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.023	w = 1/[σ2(Fo2) + (0.0208P)2] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.053	(Δ/σ)max = 0.008
S = 1.00	Δρmax = 0.32 e Å−3
1550 reflections	Δρmin = −0.53 e Å−3
127 parameters	Absolute structure: Flack (1983), 636 Friedel pairs
1 restraint	Flack parameter: 0.026 (10)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Br1	1.16169 (4)	0.62891 (2)	0.12241 (5)	0.01760 (10)
F1	0.9560 (3)	0.69267 (15)	−0.10033 (17)	0.0188 (4)
F2	0.6066 (3)	0.58458 (16)	−0.20909 (18)	0.0178 (4)
F3	0.5004 (3)	0.30738 (15)	0.08418 (15)	0.0181 (4)
F4	0.8565 (3)	0.41466 (18)	0.19058 (19)	0.0192 (4)
N1	0.3610 (4)	0.3813 (2)	−0.1276 (3)	0.0148 (6)
O1	0.3925 (4)	0.36408 (18)	−0.2245 (2)	0.0181 (5)
O2	0.1833 (3)	0.3518 (2)	−0.0760 (2)	0.0207 (6)
C1	0.8465 (4)	0.5971 (3)	−0.0542 (3)	0.0134 (7)
C2	0.6671 (4)	0.5405 (3)	−0.1118 (3)	0.0136 (7)
C3	0.5498 (4)	0.4424 (3)	−0.0658 (3)	0.0128 (7)
C4	0.6105 (5)	0.4023 (3)	0.0374 (3)	0.0146 (7)
C5	0.7936 (4)	0.4574 (3)	0.0933 (3)	0.0129 (8)
C6	0.9119 (4)	0.5558 (3)	0.0468 (3)	0.0146 (7)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Br1	0.01516 (11)	0.01875 (15)	0.01890 (19)	−0.00140 (8)	−0.00323 (18)	−0.0046 (2)
F1	0.0214 (7)	0.0153 (9)	0.0198 (13)	−0.0066 (6)	0.0011 (8)	0.0038 (8)
F2	0.0241 (8)	0.0159 (9)	0.0135 (13)	−0.0005 (7)	−0.0031 (9)	0.0027 (9)
F3	0.0224 (7)	0.0155 (9)	0.0164 (12)	−0.0057 (6)	0.0040 (8)	0.0017 (7)
F4	0.0256 (9)	0.0177 (10)	0.0142 (14)	0.0018 (7)	−0.0024 (8)	0.0009 (9)
N1	0.0150 (12)	0.0158 (15)	0.014 (2)	−0.0005 (8)	−0.0002 (11)	−0.0015 (13)
O1	0.0205 (8)	0.0206 (12)	0.0133 (16)	−0.0014 (7)	−0.0005 (10)	−0.0048 (10)
O2	0.0134 (9)	0.0245 (14)	0.0241 (17)	−0.0025 (7)	0.0025 (10)	−0.0016 (11)
C1	0.0165 (12)	0.0082 (15)	0.016 (2)	−0.0009 (10)	0.0038 (13)	0.0006 (13)
C2	0.0160 (12)	0.0125 (16)	0.012 (2)	0.0048 (9)	0.0001 (12)	−0.0004 (14)
C3	0.0099 (10)	0.0143 (15)	0.014 (2)	0.0018 (10)	0.0001 (12)	−0.0040 (13)
C4	0.0169 (12)	0.0107 (15)	0.016 (2)	0.0019 (10)	0.0045 (13)	0.0003 (13)
C5	0.0150 (10)	0.0158 (15)	0.008 (2)	0.0030 (9)	0.0001 (11)	−0.0003 (12)
C6	0.0110 (10)	0.0169 (15)	0.016 (2)	0.0014 (10)	−0.0020 (12)	−0.0065 (13)

Geometric parameters (Å, °)

Br1—C6	1.874 (3)	F4—F3iii	2.877 (2)
Br1—O1i	3.150 (2)	F4—F2vii	2.901 (2)
Br1—O1ii	3.201 (2)	N1—O1	1.217 (4)
F3—O2iii	2.823 (3)	N1—O2	1.234 (3)
F1—C1	1.342 (3)	N1—C3	1.472 (4)
F1—F2iv	2.908 (3)	O1—Br1ix	3.150 (2)
F2—C2	1.332 (4)	O1—Br1x	3.201 (2)
F2—F3v	2.863 (3)	O2—F3viii	2.823 (3)
F2—F4v	2.901 (2)	C1—C6	1.369 (5)
F2—F1vi	2.908 (3)	C1—C2	1.385 (4)
F3—C4	1.341 (3)	C2—C3	1.385 (4)
F3—F2vii	2.863 (3)	C3—C4	1.383 (5)
F3—F4viii	2.877 (2)	C4—C5	1.382 (4)
F4—C5	1.331 (4)	C5—C6	1.391 (4)
C6—Br1—O1i	155.87 (10)	N1—O1—Br1ix	134.13 (18)
C6—Br1—O1ii	124.16 (9)	N1—O1—Br1x	133.10 (18)
O1i—Br1—O1ii	73.03 (6)	Br1ix—O1—Br1x	75.36 (6)
C1—F1—F2iv	169.53 (15)	N1—O2—F3viii	144.98 (19)
C2—F2—F3v	176.03 (17)	F1—C1—C6	120.9 (3)
C2—F2—F4v	127.90 (16)	F1—C1—C2	118.2 (3)
F3v—F2—F4v	55.33 (6)	C6—C1—C2	120.8 (3)
C2—F2—F1vi	88.19 (17)	F2—C2—C3	121.5 (3)
F3v—F2—F1vi	89.86 (7)	F2—C2—C1	119.0 (3)
F4v—F2—F1vi	85.76 (7)	C3—C2—C1	119.5 (3)
C4—F3—O2iii	90.56 (18)	C4—C3—C2	120.0 (3)
C4—F3—F2vii	99.04 (18)	C4—C3—N1	120.6 (3)
O2iii—F3—F2vii	161.63 (9)	C2—C3—N1	119.5 (3)
C4—F3—F4viii	168.70 (16)	F3—C4—C5	118.4 (3)
O2iii—F3—F4viii	84.17 (8)	F3—C4—C3	121.4 (3)
F2vii—F3—F4viii	83.52 (8)	C5—C4—C3	120.1 (3)
C5—F4—F3iii	88.06 (17)	F4—C5—C4	119.5 (3)
C5—F4—F2vii	97.86 (13)	F4—C5—C6	120.7 (3)
F3iii—F4—F2vii	116.85 (8)	C4—C5—C6	119.8 (3)
O1—N1—O2	125.5 (3)	C1—C6—C5	119.7 (3)
O1—N1—C3	117.8 (2)	C1—C6—Br1	120.8 (2)
O2—N1—C3	116.6 (3)	C5—C6—Br1	119.5 (2)
O2—N1—O1—Br1ix	−164.81 (19)	F4viii—F3—C4—C5	−50.3 (12)
C3—N1—O1—Br1ix	15.2 (4)	O2iii—F3—C4—C3	65.5 (3)
O2—N1—O1—Br1x	−49.6 (4)	F2vii—F3—C4—C3	−130.3 (3)
C3—N1—O1—Br1x	130.4 (2)	F4viii—F3—C4—C3	127.4 (9)
O1—N1—O2—F3viii	110.3 (4)	C2—C3—C4—F3	−179.9 (3)
C3—N1—O2—F3viii	−69.7 (4)	N1—C3—C4—F3	0.0 (4)
F2iv—F1—C1—C6	−133.4 (10)	C2—C3—C4—C5	−2.2 (4)
F2iv—F1—C1—C2	47.2 (13)	N1—C3—C4—C5	177.7 (3)
F3v—F2—C2—C3	174 (2)	F3iii—F4—C5—C4	65.3 (3)
F4v—F2—C2—C3	30.2 (4)	F2vii—F4—C5—C4	−51.5 (3)
F1vi—F2—C2—C3	113.4 (3)	F3iii—F4—C5—C6	−113.9 (3)
F3v—F2—C2—C1	−4(3)	F2vii—F4—C5—C6	129.2 (2)
F4v—F2—C2—C1	−147.6 (2)	F3—C4—C5—F4	0.5 (4)
F1vi—F2—C2—C1	−64.4 (3)	C3—C4—C5—F4	−177.2 (2)
F1—C1—C2—F2	−1.5 (4)	F3—C4—C5—C6	179.8 (3)
C6—C1—C2—F2	179.1 (3)	C3—C4—C5—C6	2.0 (4)
F1—C1—C2—C3	−179.4 (3)	F1—C1—C6—C5	179.2 (3)
C6—C1—C2—C3	1.2 (4)	C2—C1—C6—C5	−1.4 (4)
F2—C2—C3—C4	−177.2 (3)	F1—C1—C6—Br1	−1.6 (4)
C1—C2—C3—C4	0.6 (4)	C2—C1—C6—Br1	177.8 (2)
F2—C2—C3—N1	2.9 (4)	F4—C5—C6—C1	179.0 (3)
C1—C2—C3—N1	−179.2 (3)	C4—C5—C6—C1	−0.2 (4)
O1—N1—C3—C4	−138.6 (3)	F4—C5—C6—Br1	−0.2 (4)
O2—N1—C3—C4	41.4 (4)	C4—C5—C6—Br1	−179.4 (2)
O1—N1—C3—C2	41.3 (4)	O1i—Br1—C6—C1	−143.2 (2)
O2—N1—C3—C2	−138.7 (3)	O1ii—Br1—C6—C1	86.1 (3)
O2iii—F3—C4—C5	−112.3 (3)	O1i—Br1—C6—C5	36.0 (4)
F2vii—F3—C4—C5	52.0 (3)	O1ii—Br1—C6—C5	−94.7 (2)

Symmetry codes: (i) −x+2, −y+1, z+1/2; (ii) −x+3/2, y+1/2, z+1/2; (iii) x+1/2, −y+1/2, z; (iv) x+1/2, −y+3/2, z; (v) −x+1, −y+1, z−1/2; (vi) x−1/2, −y+3/2, z; (vii) −x+1, −y+1, z+1/2; (viii) x−1/2, −y+1/2, z; (ix) −x+2, −y+1, z−1/2; (x) −x+3/2, y−1/2, z−1/2.