organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

2,4-Di­chloro-6-nitro­benzoic acid

aDepartment of Chemistry, Zhejiang University, Hangzhou 310027, People's Republic of China
*Correspondence e-mail: duzq@zju.edu.cn

(Received 29 December 2007; accepted 23 January 2008; online 30 January 2008)

The title compound, C7H3Cl2NO4, was prepared by the reaction of 2,4-dichloro-6-nitro­toluene with 20% HNO3 solution at 430 K. The carboxyl and nitro groups are twisted by 82.82 (12) and 11.9 (2)°, respectively, with respect to the benzene ring. The crystal structure is stabilized by O—H⋯O hydrogen bonding between carboxyl groups and weak C—H⋯O hydrogen bonding between the nitro group and the benzene ring of an adjacent mol­ecule.

Related literature

For general background, see: Jacobson (1997[Jacobson, S. E. (1997). US Patent No. 5 591 890.]); Langer et al. (2006[Langer, R., Rodefeld, L. & Neumann, K. H. (2006). US Patent No. 7 094 923.]); Li & Zhu (2007[Li, S.-Y. & Zhu, L.-J. (2007). CN Patent No. 100 999 457.]).

[Scheme 1]

Experimental

Crystal data
  • C7H3Cl2NO4

  • Mr = 236.00

  • Triclinic, [P \overline 1]

  • a = 4.6930 (7) Å

  • b = 7.5590 (11) Å

  • c = 13.0721 (19) Å

  • α = 97.120 (2)°

  • β = 95.267 (2)°

  • γ = 100.631 (2)°

  • V = 449.11 (11) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.71 mm−1

  • T = 295 (2) K

  • 0.40 × 0.30 × 0.20 mm

Data collection
  • Bruker SMART CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2002[Bruker (2002). SADABS (Version 2.03), SAINT (Version 6.02a) and SMART (Version 5.618). Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.765, Tmax = 0.872

  • 2415 measured reflections

  • 1641 independent reflections

  • 1457 reflections with I > 2σ(I)

  • Rint = 0.011

Refinement
  • R[F2 > 2σ(F2)] = 0.032

  • wR(F2) = 0.086

  • S = 1.06

  • 1641 reflections

  • 127 parameters

  • H-atom parameters constrained

  • Δρmax = 0.22 e Å−3

  • Δρmin = −0.34 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O4—H4A⋯O3i 0.90 1.77 2.664 (2) 173
C3—H5⋯O2ii 0.93 2.56 3.453 (2) 160
Symmetry codes: (i) -x+1, -y+2, -z+1; (ii) x-1, y-1, z.

Data collection: SMART (Bruker, 2002[Bruker (2002). SADABS (Version 2.03), SAINT (Version 6.02a) and SMART (Version 5.618). Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2002[Bruker (2002). SADABS (Version 2.03), SAINT (Version 6.02a) and SMART (Version 5.618). Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Comment top

Ortho-nitro aromatic acids have been used as intermediates of dyes, pharmaceuticals and agrochemicals (Jacobson, 1997; Langer et al., 2006). The title compound is an important chemical intermediates of a kind of synthetic dyes, pharmaceuticals (Li & Zhu, 2007). Its crystal structure is reported here.

The molecular structure of the title compound is shown in Fig. 1. The molecule displays a non-planar structure. The carboxyl and nitro groups are twisted with respect to the benzene ring by 82.82 (12) and 11.9 (2)°, respectively. Within the carboxyl group, the O3—C7 bond distance is appreciably shorter than the O4—C7 bond distance (Table 1). The crystal structure is stabilized by O—H···O hydrogen bonding between carboxyl groups and weak C—H···O hydrogen bonding between nitro group and benzene ring of adjacent molecules (Table 2).

Related literature top

For general background, see: Jacobson (1997); Langer et al. (2006); Li & Zhu (2007).

Experimental top

The title compound was prepared by a reaction of 2-nitro-4,6-dichlorotoluene (1 mmol) with 20% HNO3 solution (15 ml) in an autoclave at 430 K for 20 h. Single crystals suitable for X-ray data collection were obtained by recrystallization from a methanol solution.

Refinement top

Carboxyl H atom was located in a difference Fourier map and refined as riding in as-found relative position with Uiso(H) = 1.5Ueq(O). Other H atoms were placed in calculated positions with C—H = 0.93 Å and refined in riding mode, Uiso(H) = 1.2Ueq(C).

Computing details top

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound with 40% probability displacement ellipsoids.
2,4-Dichloro-6-nitrobenzoic acid top
Crystal data top
C7H3Cl2NO4Z = 2
Mr = 236.00F(000) = 236
Triclinic, P1Dx = 1.745 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 4.6930 (7) ÅCell parameters from 2069 reflections
b = 7.5590 (11) Åθ = 2.8–27.5°
c = 13.0721 (19) ŵ = 0.71 mm1
α = 97.120 (2)°T = 295 K
β = 95.267 (2)°Prism, colorless
γ = 100.631 (2)°0.40 × 0.30 × 0.20 mm
V = 449.11 (11) Å3
Data collection top
Bruker SMART CCD area-detector
diffractometer
1641 independent reflections
Radiation source: fine-focus sealed tube1457 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.011
ϕ and ω scansθmax = 25.5°, θmin = 2.8°
Absorption correction: multi-scan
(SADABS; Bruker, 2002)
h = 55
Tmin = 0.765, Tmax = 0.872k = 99
2415 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)] = 0.032Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.087H-atom parameters constrained
S = 1.06 w = 1/[σ2(Fo2) + (0.0463P)2 + 0.1228P]
where P = (Fo2 + 2Fc2)/3
1641 reflections(Δ/σ)max < 0.001
127 parametersΔρmax = 0.22 e Å3
0 restraintsΔρmin = 0.34 e Å3
Crystal data top
C7H3Cl2NO4γ = 100.631 (2)°
Mr = 236.00V = 449.11 (11) Å3
Triclinic, P1Z = 2
a = 4.6930 (7) ÅMo Kα radiation
b = 7.5590 (11) ŵ = 0.71 mm1
c = 13.0721 (19) ÅT = 295 K
α = 97.120 (2)°0.40 × 0.30 × 0.20 mm
β = 95.267 (2)°
Data collection top
Bruker SMART CCD area-detector
diffractometer
1641 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2002)
1457 reflections with I > 2σ(I)
Tmin = 0.765, Tmax = 0.872Rint = 0.011
2415 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0320 restraints
wR(F2) = 0.087H-atom parameters constrained
S = 1.06Δρmax = 0.22 e Å3
1641 reflectionsΔρmin = 0.34 e Å3
127 parameters
Special details top

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
Cl10.66419 (15)0.23838 (7)0.04930 (4)0.0620 (2)
Cl20.19170 (13)0.45919 (8)0.38873 (4)0.0611 (2)
N10.8796 (4)0.9077 (2)0.20929 (13)0.0425 (4)
O10.8119 (3)1.03193 (18)0.26405 (12)0.0542 (4)
O21.0647 (4)0.9276 (2)0.15015 (13)0.0651 (5)
O30.7264 (3)0.86356 (19)0.45830 (10)0.0456 (3)
O40.3076 (3)0.9004 (2)0.37628 (11)0.0540 (4)
H4A0.28860.98500.42820.081*
C10.5569 (4)0.6891 (2)0.29482 (13)0.0335 (4)
C20.4126 (4)0.5107 (3)0.29348 (14)0.0388 (4)
C30.4410 (4)0.3708 (2)0.21800 (15)0.0428 (5)
H50.34130.25250.21820.051*
C40.6193 (4)0.4107 (3)0.14305 (15)0.0413 (4)
C50.7657 (4)0.5858 (3)0.14027 (15)0.0410 (4)
H30.88520.61170.08890.049*
C60.7292 (4)0.7212 (2)0.21587 (14)0.0346 (4)
C70.5340 (4)0.8318 (2)0.38368 (14)0.0352 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0958 (5)0.0399 (3)0.0486 (3)0.0164 (3)0.0174 (3)0.0113 (2)
Cl20.0633 (4)0.0609 (4)0.0532 (3)0.0092 (3)0.0264 (3)0.0033 (3)
N10.0503 (9)0.0346 (8)0.0403 (9)0.0024 (7)0.0099 (7)0.0021 (7)
O10.0708 (10)0.0309 (7)0.0605 (9)0.0096 (6)0.0189 (7)0.0021 (6)
O20.0816 (11)0.0478 (9)0.0627 (10)0.0061 (8)0.0389 (9)0.0017 (7)
O30.0431 (7)0.0502 (8)0.0388 (7)0.0098 (6)0.0012 (6)0.0080 (6)
O40.0438 (8)0.0655 (10)0.0506 (8)0.0230 (7)0.0038 (6)0.0162 (7)
C10.0319 (9)0.0341 (9)0.0326 (9)0.0062 (7)0.0029 (7)0.0017 (7)
C20.0370 (10)0.0418 (10)0.0349 (9)0.0026 (8)0.0064 (8)0.0013 (8)
C30.0490 (11)0.0306 (9)0.0442 (11)0.0003 (8)0.0042 (9)0.0003 (8)
C40.0531 (11)0.0346 (10)0.0347 (10)0.0106 (8)0.0054 (8)0.0047 (7)
C50.0496 (11)0.0385 (10)0.0354 (10)0.0088 (8)0.0131 (8)0.0008 (8)
C60.0388 (9)0.0301 (9)0.0330 (9)0.0040 (7)0.0056 (7)0.0007 (7)
C70.0327 (9)0.0372 (10)0.0341 (9)0.0048 (7)0.0077 (7)0.0009 (7)
Geometric parameters (Å, º) top
Cl1—C41.7309 (18)C1—C21.390 (3)
Cl2—C21.7277 (19)C1—C71.510 (2)
N1—O21.216 (2)C2—C31.388 (3)
N1—O11.217 (2)C3—C41.372 (3)
N1—C61.472 (2)C3—H50.9300
O3—C71.235 (2)C4—C51.381 (3)
O4—C71.266 (2)C5—C61.377 (2)
O4—H4A0.8961C5—H30.9300
C1—C61.386 (3)
O2—N1—O1124.25 (16)C3—C4—C5121.65 (17)
O2—N1—C6117.96 (16)C3—C4—Cl1119.64 (15)
O1—N1—C6117.79 (16)C5—C4—Cl1118.71 (15)
C7—O4—H4A117.5C6—C5—C4117.98 (18)
C6—C1—C2116.50 (16)C6—C5—H3121.0
C6—C1—C7124.11 (16)C4—C5—H3121.0
C2—C1—C7119.26 (16)C5—C6—C1123.15 (17)
C3—C2—C1122.11 (17)C5—C6—N1117.00 (16)
C3—C2—Cl2118.41 (15)C1—C6—N1119.84 (15)
C1—C2—Cl2119.48 (14)O3—C7—O4126.27 (17)
C4—C3—C2118.60 (17)O3—C7—C1117.77 (15)
C4—C3—H5120.7O4—C7—C1115.83 (15)
C2—C3—H5120.7
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O4—H4A···O3i0.901.772.664 (2)173
C3—H5···O2ii0.932.563.453 (2)160
Symmetry codes: (i) x+1, y+2, z+1; (ii) x1, y1, z.

Experimental details

Crystal data
Chemical formulaC7H3Cl2NO4
Mr236.00
Crystal system, space groupTriclinic, P1
Temperature (K)295
a, b, c (Å)4.6930 (7), 7.5590 (11), 13.0721 (19)
α, β, γ (°)97.120 (2), 95.267 (2), 100.631 (2)
V3)449.11 (11)
Z2
Radiation typeMo Kα
µ (mm1)0.71
Crystal size (mm)0.40 × 0.30 × 0.20
Data collection
DiffractometerBruker SMART CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2002)
Tmin, Tmax0.765, 0.872
No. of measured, independent and
observed [I > 2σ(I)] reflections
2415, 1641, 1457
Rint0.011
(sin θ/λ)max1)0.606
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.032, 0.087, 1.06
No. of reflections1641
No. of parameters127
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.22, 0.34

Computer programs: SMART (Bruker, 2002), SAINT (Bruker, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).

Selected bond lengths (Å) top
O3—C71.235 (2)O4—C71.266 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O4—H4A···O3i0.901.772.664 (2)173
C3—H5···O2ii0.932.563.453 (2)160
Symmetry codes: (i) x+1, y+2, z+1; (ii) x1, y1, z.
 

Acknowledgements

The work was supported by the National Natural Science Foundation of China (grant No. 20376071).

References

First citationBruker (2002). SADABS (Version 2.03), SAINT (Version 6.02a) and SMART (Version 5.618). Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals Google Scholar
First citationJacobson, S. E. (1997). US Patent No. 5 591 890.  Google Scholar
First citationLanger, R., Rodefeld, L. & Neumann, K. H. (2006). US Patent No. 7 094 923.  Google Scholar
First citationLi, S.-Y. & Zhu, L.-J. (2007). CN Patent No. 100 999 457.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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ISSN: 2056-9890
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