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The crystal structure of the title compound, C8H7FN2O3, shows that the amide and nitro groups are rotated slightly out of the aromatic plane, with dihedral angles of 16.30 (6) and 29.60 (10)°, respectively. The overall molecular organization is stabilized by well defined intermolecular hydrogen bonds that lead to the formation of infinite chains.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801010704/tk6018sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801010704/tk6018Isup2.hkl
Contains datablock I

CCDC reference: 170886

Key indicators

  • Single-crystal X-ray study
  • T = 294 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.050
  • wR factor = 0.168
  • Data-to-parameter ratio = 15.5

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry








Comment top

One of the structural characteristics of 4'-fluoro-2'-nitroacetanilide, (I), is the presence of a pair of the electron-donating (–NH2) and electron-withdrawing (–NO2) groups, a feature which enhances the dipole moments of this molecule through both inductive and resonance effects (Fletton et al., 1986). In addition, molecule (I) contains a single fluoride substituent on its aromatic ring, the signal of which can be easily detected via 19F NMR methods. A molecule possessing such structural characteristics in crystalline form is deemed to be an ideal candidate for the examination of the hypothesis of time-reversal symmetry violation, a physics theory postulated in the recent years (Li & Nadin, 1995, 1998). As part of our efforts investigating this theory, we present the crystal structure of (I).

The amide group in (I) (Fig. 1) is rotated out of the ring plane, with a dihedral angle of 16.30 (6)°. Similarly, the nitro group is slightly twisted out of the aromatic ring plane by 29.60 (10)°. The amide N atom approaches the amide O atom of an adjacent molecule at a distance of 2.9536 (16) Å, indicating intermolecular hydrogen bonding. It is also noted that (I) crystallizes in a centrosymmetric space group.

According to the theory of time-reversal symmetry violation (Li & Nadin, 1995, 1998), the magnitudes of the two electric currents operating in opposite directions along the same aromatic ring of (I) will be different, thus resulting in two different signals for the chemical shifts of F atom in (I). Studies into this effect are underway.

Experimental top

The title compound was acquired from a commercial source (Aldrich). The crystal used for the data collection was obtained by slow evaporation from acetone–water (2:1) saturated solution at room temperature.

Refinement top

The C-bound H atoms were placed in their geometrically calculated positions and included in the final refinement in the riding-model approximation.

Computing details top

Data collection: SMART (Siemens, 1995); cell refinement: SMART; data reduction: SHELXTL-NT (Siemens, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL-NT; software used to prepare material for publication: SHELXTL-NT.

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) with ellipsoids at the 30% probability level (Bruker, 1995).
4'-fluoro-2'-nitroacetanilide top
Crystal data top
C8H7FN2O3? # Insert any comments here.
Mr = 198.16Dx = 1.531 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 3.9758 (7) ÅCell parameters from 2891 reflections
b = 22.489 (4) Åθ = 1–27.5°
c = 9.7419 (16) ŵ = 0.13 mm1
β = 99.255 (3)°T = 294 K
V = 859.7 (3) Å3Prism, colorless
Z = 40.20 × 0.18 × 0.16 mm
F(000) = 408
Data collection top
CCD area-detector
diffractometer
1984 independent reflections
Radiation source: fine-focus sealed tube1284 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.024
ϕ and ω scansθmax = 27.6°, θmin = 1.8°
Absorption correction: empirical (using intensity measurements)
(SADABS; Sheldrick, 1996)
h = 35
Tmin = 0.974, Tmax = 0.979k = 2829
5833 measured reflectionsl = 1212
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.050H-atom parameters constrained
wR(F2) = 0.168 w = 1/[σ2(Fo2) + (0.1P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.06(Δ/σ)max = 0.001
1978 reflectionsΔρmax = 0.36 e Å3
128 parametersΔρmin = 0.27 e Å3
Crystal data top
C8H7FN2O3V = 859.7 (3) Å3
Mr = 198.16Z = 4
Monoclinic, P21/cMo Kα radiation
a = 3.9758 (7) ŵ = 0.13 mm1
b = 22.489 (4) ÅT = 294 K
c = 9.7419 (16) Å0.20 × 0.18 × 0.16 mm
β = 99.255 (3)°
Data collection top
CCD area-detector
diffractometer
1984 independent reflections
Absorption correction: empirical (using intensity measurements)
(SADABS; Sheldrick, 1996)
1284 reflections with I > 2σ(I)
Tmin = 0.974, Tmax = 0.979Rint = 0.024
5833 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0500 restraints
wR(F2) = 0.168H-atom parameters constrained
S = 1.06Δρmax = 0.36 e Å3
1978 reflectionsΔρmin = 0.27 e Å3
128 parameters
Special details top

Experimental. ? #Insert any special details here.

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
F10.1764 (4)0.48038 (5)0.13792 (14)0.0918 (4)
O10.3856 (5)0.56838 (6)0.57282 (13)0.0834 (5)
O20.5886 (3)0.65023 (5)0.50742 (12)0.0596 (3)
O30.1745 (4)0.74926 (5)0.10882 (11)0.0608 (4)
N10.3966 (4)0.60772 (6)0.48671 (13)0.0494 (3)
N20.1221 (4)0.71019 (5)0.31778 (12)0.0436 (3)
H2B0.12820.71790.40460.052*
C10.1738 (4)0.60185 (7)0.35285 (14)0.0422 (4)
C20.0921 (5)0.54448 (7)0.30961 (17)0.0530 (4)
H2A0.16950.51210.36530.064*
C30.1050 (5)0.53653 (8)0.18310 (19)0.0602 (5)
C40.2316 (5)0.58320 (8)0.10011 (19)0.0601 (5)
H4A0.36540.57650.01400.072*
C50.1565 (5)0.64031 (7)0.14688 (17)0.0497 (4)
H5A0.24900.67220.09290.060*
C60.0549 (4)0.65141 (7)0.27332 (14)0.0404 (4)
C70.1781 (4)0.75578 (7)0.23279 (14)0.0414 (4)
C80.2416 (5)0.81489 (7)0.30182 (17)0.0556 (5)
H8D0.27750.84420.23390.083*
H8A0.44000.81260.37220.083*
H8B0.04800.82600.34370.083*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
F10.1200 (10)0.0569 (7)0.0939 (9)0.0204 (7)0.0035 (7)0.0253 (6)
O10.1242 (13)0.0670 (9)0.0540 (7)0.0045 (8)0.0011 (8)0.0191 (6)
O20.0580 (8)0.0673 (7)0.0502 (7)0.0008 (6)0.0010 (6)0.0042 (6)
O30.0953 (9)0.0570 (7)0.0325 (5)0.0032 (6)0.0180 (6)0.0046 (5)
N10.0583 (8)0.0512 (7)0.0392 (6)0.0122 (7)0.0092 (6)0.0024 (6)
N20.0619 (8)0.0423 (7)0.0268 (5)0.0009 (6)0.0073 (5)0.0000 (5)
C10.0449 (8)0.0460 (8)0.0378 (7)0.0026 (7)0.0129 (6)0.0008 (6)
C20.0621 (11)0.0452 (9)0.0533 (9)0.0027 (8)0.0138 (8)0.0005 (7)
C30.0670 (12)0.0508 (10)0.0650 (10)0.0113 (9)0.0173 (9)0.0154 (8)
C40.0602 (11)0.0706 (12)0.0476 (9)0.0083 (9)0.0022 (8)0.0129 (8)
C50.0510 (9)0.0564 (10)0.0408 (8)0.0039 (8)0.0047 (7)0.0024 (7)
C60.0442 (8)0.0455 (8)0.0336 (7)0.0004 (6)0.0122 (6)0.0013 (6)
C70.0457 (8)0.0473 (8)0.0316 (7)0.0039 (7)0.0069 (6)0.0055 (6)
C80.0732 (12)0.0500 (10)0.0446 (8)0.0072 (9)0.0123 (8)0.0018 (7)
Geometric parameters (Å, º) top
F1—C31.352 (2)C2—H2A0.9300
O1—N11.2249 (18)C3—C41.370 (3)
O2—N11.2197 (18)C4—C51.379 (2)
O3—C71.2144 (17)C4—H4A0.9300
N1—C11.4598 (19)C5—C61.398 (2)
N2—C71.3585 (18)C5—H5A0.9300
N2—C61.4032 (19)C7—C81.493 (2)
N2—H2B0.8600C8—H8D0.9600
C1—C21.380 (2)C8—H8A0.9600
C1—C61.396 (2)C8—H8B0.9600
C2—C31.362 (2)
O2—N1—O1122.90 (14)C5—C4—H4A120.7
O2—N1—C1119.49 (13)C4—C5—C6121.66 (16)
O1—N1—C1117.59 (14)C4—C5—H5A119.2
C7—N2—C6124.37 (12)C6—C5—H5A119.2
C7—N2—H2B117.8C1—C6—C5116.66 (14)
C6—N2—H2B117.8C1—C6—N2123.38 (13)
C2—C1—C6122.35 (14)C5—C6—N2119.87 (13)
C2—C1—N1115.89 (14)O3—C7—N2122.56 (14)
C6—C1—N1121.76 (14)O3—C7—C8121.97 (14)
C3—C2—C1118.18 (15)N2—C7—C8115.46 (12)
C3—C2—H2A120.9C7—C8—H8D109.5
C1—C2—H2A120.9C7—C8—H8A109.5
F1—C3—C4119.04 (16)H8D—C8—H8A109.5
F1—C3—C2118.51 (16)C7—C8—H8B109.5
C4—C3—C2122.45 (16)H8D—C8—H8B109.5
C3—C4—C5118.62 (16)H8A—C8—H8B109.5
C3—C4—H4A120.7
O2—N1—C1—C2150.10 (15)C2—C1—C6—C50.7 (2)
O1—N1—C1—C228.4 (2)N1—C1—C6—C5179.94 (14)
O2—N1—C1—C629.2 (2)C2—C1—C6—N2177.08 (15)
O1—N1—C1—C6152.28 (16)N1—C1—C6—N23.7 (2)
C6—C1—C2—C31.6 (3)C4—C5—C6—C12.8 (3)
N1—C1—C2—C3177.67 (15)C4—C5—C6—N2179.35 (16)
C1—C2—C3—F1177.73 (16)C7—N2—C6—C1143.82 (16)
C1—C2—C3—C41.9 (3)C7—N2—C6—C539.9 (2)
F1—C3—C4—C5179.78 (18)C6—N2—C7—O30.0 (3)
C2—C3—C4—C50.1 (3)C6—N2—C7—C8179.46 (15)
C3—C4—C5—C62.6 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2B···O3i0.862.102.9536 (16)170
Symmetry code: (i) x, y+3/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC8H7FN2O3
Mr198.16
Crystal system, space groupMonoclinic, P21/c
Temperature (K)294
a, b, c (Å)3.9758 (7), 22.489 (4), 9.7419 (16)
β (°) 99.255 (3)
V3)859.7 (3)
Z4
Radiation typeMo Kα
µ (mm1)0.13
Crystal size (mm)0.20 × 0.18 × 0.16
Data collection
DiffractometerCCD area-detector
diffractometer
Absorption correctionEmpirical (using intensity measurements)
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.974, 0.979
No. of measured, independent and
observed [I > 2σ(I)] reflections
5833, 1984, 1284
Rint0.024
(sin θ/λ)max1)0.652
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.050, 0.168, 1.06
No. of reflections1978
No. of parameters128
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.36, 0.27

Computer programs: SMART (Siemens, 1995), SMART, SHELXTL-NT (Siemens, 1995), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), SHELXTL-NT.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2B···O3i0.862.102.9536 (16)170
Symmetry code: (i) x, y+3/2, z+1/2.
 

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