1,2,4,5-Tetra­fluoro-3,6-bis­(nitro­meth­yl)benzene

The title compound, C₈H₄F₄N₂O₄, crystallizes on a site of crystallographic inversion symmetry.

Key indicators

• Single-crystal X-ray study
• T = 299 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.038
• wR factor = 0.106
• Data-to-parameter ratio = 11.5

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N1
PLAT482_ALERT_4_C Small D-H..A Angle Rep for C4     ..  F2      ..      97.00 Deg.
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       1.11 Ratio

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   3 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2001); cell refinement: CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1998).

1,2,4,5-Tetrafluoro-3,6-bis(nitromethyl)benzene

Crystal data

C8H4F4N2O4	F(000) = 536
Mr = 268.13	Dx = 1.848 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C_2yc	Cell parameters from 1596 reflections
a = 17.570 (4) Å	θ = 2.7–25.4°
b = 7.2870 (15) Å	µ = 0.20 mm^−1
c = 8.5746 (17) Å	T = 299 K
β = 118.62 (3)°	Block, colourless
V = 963.7 (4) Å^3	0.5 × 0.5 × 0.32 mm
Z = 4

Data collection

Oxford Diffraction Xcalibur CCD diffractometer	977 independent reflections
Radiation source: fine-focus sealed tube	825 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.016
ω and φ scans	θmax = 26.4°, θmin = 4.5°
Absorption correction: analytical (Clark & Reid, 1995)	h = −20→21
Tmin = 0.877, Tmax = 0.958	k = −9→9
2981 measured reflections	l = −10→8

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.106	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0525P)^2 + 0.7257P] where P = (Fo^2 + 2Fc^2)/3
977 reflections	(Δ/σ)max = 0.001
85 parameters	Δρmax = 0.23 e Å^−3
0 restraints	Δρmin = −0.20 e Å^−3

Special details

Experimental. face-indexed (CrysAlis RED; Oxford Diffraction, 2003)

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
F1	1.02267 (8)	0.15067 (16)	0.42759 (17)	0.0653 (4)
F2	0.84544 (7)	0.61604 (18)	0.45685 (18)	0.0683 (4)
N1	0.84419 (9)	0.1525 (2)	0.5065 (2)	0.0457 (4)
C2	0.92949 (10)	0.3768 (2)	0.4354 (2)	0.0424 (4)
C3	0.92146 (11)	0.5559 (3)	0.4767 (2)	0.0445 (4)
C1	1.00998 (11)	0.3241 (2)	0.4615 (2)	0.0434 (4)
C4	0.85428 (12)	0.2474 (3)	0.3629 (2)	0.0526 (5)
H4A	0.8016	0.3149	0.2881	0.079 (7)*
H4B	0.8623	0.1562	0.2896	0.081 (8)*
O1	0.89117 (12)	0.1920 (3)	0.6587 (2)	0.0801 (6)
O2	0.78876 (11)	0.0375 (3)	0.4604 (2)	0.0822 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
F1	0.0789 (9)	0.0405 (6)	0.0758 (8)	−0.0012 (5)	0.0366 (7)	−0.0078 (5)
F2	0.0474 (7)	0.0717 (9)	0.0881 (9)	0.0048 (6)	0.0344 (6)	0.0024 (6)
N1	0.0436 (8)	0.0423 (8)	0.0544 (9)	−0.0032 (6)	0.0259 (7)	0.0006 (6)
C2	0.0434 (9)	0.0442 (9)	0.0350 (8)	−0.0093 (7)	0.0152 (7)	0.0028 (7)
C3	0.0408 (9)	0.0485 (10)	0.0439 (9)	0.0005 (7)	0.0201 (7)	0.0051 (7)
C1	0.0522 (10)	0.0358 (8)	0.0407 (9)	−0.0015 (7)	0.0211 (7)	0.0020 (7)
C4	0.0510 (10)	0.0558 (11)	0.0422 (9)	−0.0168 (8)	0.0152 (8)	0.0021 (8)
O1	0.1026 (13)	0.0891 (12)	0.0483 (8)	−0.0329 (10)	0.0359 (8)	−0.0044 (8)
O2	0.0764 (11)	0.0825 (12)	0.0880 (12)	−0.0413 (9)	0.0396 (9)	−0.0029 (9)

Geometric parameters (Å, º)

F1—C1	1.339 (2)	C2—C3	1.377 (3)
F2—C3	1.337 (2)	C2—C4	1.495 (2)
N1—O1	1.198 (2)	C3—C1^i	1.373 (2)
N1—O2	1.200 (2)	C1—C3^i	1.373 (2)
N1—C4	1.494 (2)	C4—H4A	0.9700
C2—C1	1.376 (2)	C4—H4B	0.9700
O1—N1—O2	123.6 (2)	F1—C1—C3^i	118.58 (16)
O1—N1—C4	119.65 (15)	F1—C1—C2	119.5 (2)
O2—N1—C4	116.72 (16)	C3^i—C1—C2	121.87 (17)
C1—C2—C3	116.52 (15)	N1—C4—C2	112.30 (14)
C1—C2—C4	121.76 (17)	N1—C4—H4A	109.1
C3—C2—C4	121.71 (17)	C2—C4—H4A	109.1
F2—C3—C1^i	118.60 (17)	N1—C4—H4B	109.1
F2—C3—C2	119.8 (2)	C2—C4—H4B	109.1
C1^i—C3—C2	121.60 (16)	H4A—C4—H4B	107.9
C1—C2—C3—F2	−179.14 (14)	C3—C2—C1—C3^i	−0.8 (3)
C4—C2—C3—F2	1.9 (2)	C4—C2—C1—C3^i	178.13 (15)
C1—C2—C3—C1^i	0.8 (3)	O1—N1—C4—C2	3.8 (3)
C4—C2—C3—C1^i	−178.14 (15)	O2—N1—C4—C2	−175.40 (18)
C3—C2—C1—F1	178.57 (15)	C1—C2—C4—N1	94.0 (2)
C4—C2—C1—F1	−2.5 (2)	C3—C2—C4—N1	−87.1 (2)

Symmetry code: (i) −x+2, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4A···F2	0.97	2.54	2.830 (3)	97
C4—H4B···F1	0.97	2.48	2.826 (2)	101
C4—H4A···O2^ii	0.97	2.54	3.435 (5)	153

Symmetry code: (ii) −x+3/2, y+1/2, −z+1/2.