2,4-Dichloro-6-nitro­benzoic acid

Liu, H.-L.; Du, Z.-Q.

doi:10.1107/S1600536808002560

organic compounds

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ISSN: 2056-9890

Volume 64| Part 2| February 2008| Page o536

doi:10.1107/S1600536808002560

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2,4-Dichloro-6-nitrobenzoic acid

Hai-Lian Liu ^a and Zhi-Qiang Du ^a ^*

^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 ); Langer et al. (2006 ); Li & Zhu (2007 ).

Experimental

Crystal data

C₇H₃Cl₂NO₄
M_r = 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 ) T_min = 0.765, T_max = 0.872
2415 measured reflections
1641 independent reflections
1457 reflections with I > 2σ(I)
R_int = 0.011

Refinement

R[F² > 2σ(F²)] = 0.032
wR(F²) = 0.086
S = 1.06
1641 reflections
127 parameters
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.34 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	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); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; 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 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808002560/xu2399sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808002560/xu2399Isup2.hkl

checkCIF report

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.

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

Fig. 1. The molecular structure of the title compound with 40% probability displacement ellipsoids.

2,4-Dichloro-6-nitrobenzoic acid top

Crystal data top

C₇H₃Cl₂NO₄	Z = 2
M_r = 236.00	F(000) = 236
Triclinic, P1	D_x = 1.745 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 4.6930 (7) Å	Cell parameters from 2069 reflections
b = 7.5590 (11) Å	θ = 2.8–27.5°
c = 13.0721 (19) Å	µ = 0.71 mm⁻¹
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 tube	1457 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.011
ϕ and ω scans	θ_max = 25.5°, θ_min = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −5→5
T_min = 0.765, T_max = 0.872	k = −9→9
2415 measured reflections	l = −15→15

Refinement top

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)] = 0.032	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.087	H-atom parameters constrained
S = 1.06	w = 1/[σ²(F_o²) + (0.0463P)² + 0.1228P] where P = (F_o² + 2F_c²)/3
1641 reflections	(Δ/σ)_max < 0.001
127 parameters	Δρ_max = 0.22 e Å⁻³
0 restraints	Δρ_min = −0.34 e Å⁻³

Crystal data top

C₇H₃Cl₂NO₄	γ = 100.631 (2)°
M_r = 236.00	V = 449.11 (11) Å³
Triclinic, P1	Z = 2
a = 4.6930 (7) Å	Mo Kα radiation
b = 7.5590 (11) Å	µ = 0.71 mm⁻¹
c = 13.0721 (19) Å	T = 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)
T_min = 0.765, T_max = 0.872	R_int = 0.011
2415 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.032	0 restraints
wR(F²) = 0.087	H-atom parameters constrained
S = 1.06	Δρ_max = 0.22 e Å⁻³
1641 reflections	Δρ_min = −0.34 e Å⁻³
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

	x	y	z	U_iso*/U_eq
Cl1	0.66419 (15)	0.23838 (7)	0.04930 (4)	0.0620 (2)
Cl2	0.19170 (13)	0.45919 (8)	0.38873 (4)	0.0611 (2)
N1	0.8796 (4)	0.9077 (2)	0.20929 (13)	0.0425 (4)
O1	0.8119 (3)	1.03193 (18)	0.26405 (12)	0.0542 (4)
O2	1.0647 (4)	0.9276 (2)	0.15015 (13)	0.0651 (5)
O3	0.7264 (3)	0.86356 (19)	0.45830 (10)	0.0456 (3)
O4	0.3076 (3)	0.9004 (2)	0.37628 (11)	0.0540 (4)
H4A	0.2886	0.9850	0.4282	0.081*
C1	0.5569 (4)	0.6891 (2)	0.29482 (13)	0.0335 (4)
C2	0.4126 (4)	0.5107 (3)	0.29348 (14)	0.0388 (4)
C3	0.4410 (4)	0.3708 (2)	0.21800 (15)	0.0428 (5)
H5	0.3413	0.2525	0.2182	0.051*
C4	0.6193 (4)	0.4107 (3)	0.14305 (15)	0.0413 (4)
C5	0.7657 (4)	0.5858 (3)	0.14027 (15)	0.0410 (4)
H3	0.8852	0.6117	0.0889	0.049*
C6	0.7292 (4)	0.7212 (2)	0.21587 (14)	0.0346 (4)
C7	0.5340 (4)	0.8318 (2)	0.38368 (14)	0.0352 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0958 (5)	0.0399 (3)	0.0486 (3)	0.0164 (3)	0.0174 (3)	−0.0113 (2)
Cl2	0.0633 (4)	0.0609 (4)	0.0532 (3)	−0.0092 (3)	0.0264 (3)	0.0033 (3)
N1	0.0503 (9)	0.0346 (8)	0.0403 (9)	0.0024 (7)	0.0099 (7)	0.0021 (7)
O1	0.0708 (10)	0.0309 (7)	0.0605 (9)	0.0096 (6)	0.0189 (7)	−0.0021 (6)
O2	0.0816 (11)	0.0478 (9)	0.0627 (10)	−0.0061 (8)	0.0389 (9)	0.0017 (7)
O3	0.0431 (7)	0.0502 (8)	0.0388 (7)	0.0098 (6)	−0.0012 (6)	−0.0080 (6)
O4	0.0438 (8)	0.0655 (10)	0.0506 (8)	0.0230 (7)	0.0038 (6)	−0.0162 (7)
C1	0.0319 (9)	0.0341 (9)	0.0326 (9)	0.0062 (7)	0.0029 (7)	−0.0017 (7)
C2	0.0370 (10)	0.0418 (10)	0.0349 (9)	0.0026 (8)	0.0064 (8)	0.0013 (8)
C3	0.0490 (11)	0.0306 (9)	0.0442 (11)	0.0003 (8)	0.0042 (9)	0.0003 (8)
C4	0.0531 (11)	0.0346 (10)	0.0347 (10)	0.0106 (8)	0.0054 (8)	−0.0047 (7)
C5	0.0496 (11)	0.0385 (10)	0.0354 (10)	0.0088 (8)	0.0131 (8)	0.0008 (8)
C6	0.0388 (9)	0.0301 (9)	0.0330 (9)	0.0040 (7)	0.0056 (7)	0.0007 (7)
C7	0.0327 (9)	0.0372 (10)	0.0341 (9)	0.0048 (7)	0.0077 (7)	−0.0009 (7)

Geometric parameters (Å, º) top

Cl1—C4	1.7309 (18)	C1—C2	1.390 (3)
Cl2—C2	1.7277 (19)	C1—C7	1.510 (2)
N1—O2	1.216 (2)	C2—C3	1.388 (3)
N1—O1	1.217 (2)	C3—C4	1.372 (3)
N1—C6	1.472 (2)	C3—H5	0.9300
O3—C7	1.235 (2)	C4—C5	1.381 (3)
O4—C7	1.266 (2)	C5—C6	1.377 (2)
O4—H4A	0.8961	C5—H3	0.9300
C1—C6	1.386 (3)

O2—N1—O1	124.25 (16)	C3—C4—C5	121.65 (17)
O2—N1—C6	117.96 (16)	C3—C4—Cl1	119.64 (15)
O1—N1—C6	117.79 (16)	C5—C4—Cl1	118.71 (15)
C7—O4—H4A	117.5	C6—C5—C4	117.98 (18)
C6—C1—C2	116.50 (16)	C6—C5—H3	121.0
C6—C1—C7	124.11 (16)	C4—C5—H3	121.0
C2—C1—C7	119.26 (16)	C5—C6—C1	123.15 (17)
C3—C2—C1	122.11 (17)	C5—C6—N1	117.00 (16)
C3—C2—Cl2	118.41 (15)	C1—C6—N1	119.84 (15)
C1—C2—Cl2	119.48 (14)	O3—C7—O4	126.27 (17)
C4—C3—C2	118.60 (17)	O3—C7—C1	117.77 (15)
C4—C3—H5	120.7	O4—C7—C1	115.83 (15)
C2—C3—H5	120.7

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	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.

Experimental details

Crystal data
Chemical formula	C₇H₃Cl₂NO₄
M_r	236.00
Crystal system, space group	Triclinic, 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)
V (Å³)	449.11 (11)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.71
Crystal size (mm)	0.40 × 0.30 × 0.20

Data collection
Diffractometer	Bruker SMART CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2002)
T_min, T_max	0.765, 0.872
No. of measured, independent and observed [I > 2σ(I)] reflections	2415, 1641, 1457
R_int	0.011
(sin θ/λ)_max (Å⁻¹)	0.606

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.032, 0.087, 1.06
No. of reflections	1641
No. of parameters	127
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	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—C7

1.235 (2)

O4—C7

1.266 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	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.

Acknowledgements

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

References

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