2-Chloro-5-nitro­aniline

The mol­ecule of the title compound, C₆H₅ClN₂O₂, is close to being planar (rms deviation = 0.032 Å for all non-H atoms), with a maximum deviation of −0.107 (3) Å for an O atom. In the crystal structure, inter­molecular N—H...O and N—H...N inter­actions link the mol­ecules into a three-dimensional network.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.023
• wR factor = 0.061
• Data-to-parameter ratio = 11.8

checkCIF/PLATON results

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Alert level G
PLAT128_ALERT_4_G Non-standard setting of Space-group P21/c   ....      P21/n

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 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
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Substituted nitrobenzene and aniline derivatives are valuable as intermediates towards a variety of dye and pigments, heterocycles, pesticides, rubber chemicals and agricultural products, and are useful as textile printing agents, nickel stripping agents and polymerization catalysts. Thus, then title compound is an important intermediate or starting point in the syntheses of alkyl derivatives of 2-aminobenzenethiols substituted by chloro and nitro groups (Wang et al., 2000), donor-bridge-acceptor' triad compounds containing the aromatic sulfur bridges (Yosuke et al., 2003), pyridazinobenzodiazepin-5-ones as non-nucleoside HIV Reverse Transcriptase Inhibitors (Heinisch et al., 1997) and 2-chloro-5,6-dihalo-D-ribofuranosylbenzimidazoles as potential agents for human cytomegalovirus infections (Zou et al., 1997). We report herein the crystal structure of the title compound, as a key starting point towards many heterocycles.

In the molecule of the title compound (Fig 1), the bond lengths (Allen et al., 1987) and angles are within normal ranges, and may be compared with the corresponding values in N-tert-butyl-4-chloro-5-methyl-2-nitroaniline (Zhang et al., 2004). Ring A (C1–C6) is, of course, planar. Atoms Cl1, O1, O2, N1 and N2 are 0.019 (3), 0.104 (3), -0.107 (3), 0.003 (3) and -0.066 (3) Å away from the ring plane, respectively. So, the molecule is nearly planar.

In the crystal structure, intermolecular N—H···O and N—H···N hydrogen bonds (Table 1) link the molecules into a network, in which they may be effective in the stabilization of the structure.

Related literature

For applications of substituted nitrobenzene and aniline derivatives, see: Heinisch et al. (1997); Wang et al. (2000); Yosuke et al. (2003); Zou et al. (1997). For a related structure, see: Zhang et al. (2004). For bond-length data, see: Allen et al. (1987). For synthesis, see: Suwanprasop et al. (2003).

S2. Experimental

The title compound was prepared by nitration and selective reduction of 4-nitroaniline according to the literature method (Suwanprasop et al., 2003). Recrystallization from methanol afforded the title compound. Anal. calcd. for C₆H₅Cl_N2_O2: C, 41.76; H, 2.92; N, 16.23%; found: C, 41.71; H, 2.97; N, 16.16%

S3. Refinement

H atoms (for NH₂) were located in a difference synthesis and refined isotropically. The remaining H atoms were positioned geometrically, with C—H = 0.95 Å for aromatic H and constrained to ride on their parent atoms, with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-RED (Stoe & Cie, 2001); data reduction: X-RED (Stoe & Cie, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

2-Chloro-5-nitroaniline

Crystal data

C6H5ClN2O2	F(000) = 352
Mr = 172.57	Dx = 1.648 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 7189 reflections
a = 13.6233 (10) Å	θ = 3.4–25.9°
b = 3.7445 (3) Å	µ = 0.49 mm^−1
c = 13.6420 (9) Å	T = 173 K
β = 91.768 (5)°	Block, orange
V = 695.58 (9) Å^3	0.35 × 0.34 × 0.29 mm
Z = 4

Data collection

Stoe IPDSII two-circle diffractometer	1300 independent reflections
Radiation source: fine-focus sealed tube	1266 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.034
ω scans	θmax = 25.5°, θmin = 3.4°
Absorption correction: multi-scan (MULABS; Blessing, 1995)	h = −16→14
Tmin = 0.847, Tmax = 0.871	k = −4→4
5108 measured reflections	l = −16→16

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.023	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.061	w = 1/[σ^2(Fo^2) + (0.0448P)^2 + 0.0466P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max = 0.001
1300 reflections	Δρmax = 0.20 e Å^−3
110 parameters	Δρmin = −0.21 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.034 (4)

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
Cl1	0.91913 (3)	0.59906 (8)	0.62642 (3)	0.02963 (14)
O1	0.50548 (9)	0.8247 (4)	0.37207 (9)	0.0385 (3)
O2	0.60383 (10)	1.0787 (4)	0.27322 (9)	0.0475 (4)
N1	0.58750 (10)	0.9201 (3)	0.34951 (9)	0.0258 (3)
N2	0.70761 (10)	0.4832 (4)	0.66629 (9)	0.0255 (3)
H2B	0.7582 (18)	0.367 (5)	0.6920 (18)	0.043 (6)*
H2A	0.6514 (17)	0.384 (4)	0.6685 (15)	0.029 (5)*
C1	0.82203 (10)	0.6968 (3)	0.54548 (10)	0.0215 (3)
C2	0.72634 (11)	0.6173 (3)	0.57428 (10)	0.0203 (3)
C3	0.64960 (10)	0.6935 (3)	0.50720 (10)	0.0206 (3)
H3	0.5836	0.6427	0.5230	0.025*
C4	0.67060 (10)	0.8434 (3)	0.41772 (10)	0.0206 (3)
C5	0.76477 (11)	0.9244 (3)	0.38893 (11)	0.0231 (3)
H5	0.7764	1.0285	0.3269	0.028*
C6	0.84118 (11)	0.8461 (4)	0.45509 (11)	0.0248 (3)
H6	0.9070	0.8952	0.4383	0.030*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0223 (2)	0.03330 (19)	0.0329 (2)	0.00210 (13)	−0.00586 (12)	−0.00076 (14)
O1	0.0221 (6)	0.0617 (7)	0.0315 (6)	−0.0054 (5)	−0.0011 (4)	0.0122 (5)
O2	0.0374 (7)	0.0750 (10)	0.0298 (6)	−0.0099 (6)	−0.0040 (5)	0.0271 (6)
N1	0.0252 (7)	0.0302 (6)	0.0218 (6)	−0.0012 (5)	0.0000 (5)	0.0029 (5)
N2	0.0266 (7)	0.0291 (6)	0.0206 (6)	−0.0039 (6)	−0.0011 (5)	0.0041 (5)
C1	0.0215 (7)	0.0184 (5)	0.0245 (7)	0.0006 (5)	−0.0014 (5)	−0.0047 (5)
C2	0.0246 (7)	0.0181 (6)	0.0182 (7)	−0.0004 (5)	0.0014 (5)	−0.0026 (4)
C3	0.0204 (6)	0.0216 (6)	0.0201 (6)	−0.0019 (5)	0.0034 (5)	−0.0021 (5)
C4	0.0222 (7)	0.0196 (6)	0.0198 (6)	0.0001 (5)	0.0006 (5)	−0.0015 (5)
C5	0.0257 (7)	0.0235 (6)	0.0203 (7)	−0.0021 (5)	0.0060 (6)	−0.0007 (5)
C6	0.0199 (7)	0.0247 (6)	0.0301 (7)	−0.0009 (5)	0.0054 (5)	−0.0027 (5)

Geometric parameters (Å, º)

N1—O1	1.2216 (19)	C2—C3	1.397 (2)
N1—O2	1.2245 (18)	C3—C4	1.382 (2)
N2—H2B	0.88 (3)	C3—H3	0.9500
N2—H2A	0.85 (2)	C4—C5	1.387 (2)
C1—C6	1.386 (2)	C4—N1	1.4713 (18)
C1—C2	1.405 (2)	C5—C6	1.388 (2)
C1—Cl1	1.7357 (14)	C5—H5	0.9500
C2—N2	1.3830 (18)	C6—H6	0.9500
O1—N1—O2	123.19 (14)	C4—C3—C2	119.37 (12)
O1—N1—C4	118.40 (12)	C4—C3—H3	120.3
O2—N1—C4	118.41 (13)	C2—C3—H3	120.3
C2—N2—H2B	112.2 (15)	C3—C4—C5	123.90 (13)
C2—N2—H2A	112.4 (14)	C3—C4—N1	117.51 (12)
H2B—N2—H2A	117.7 (18)	C5—C4—N1	118.59 (13)
C6—C1—C2	122.42 (13)	C4—C5—C6	116.84 (13)
C6—C1—Cl1	119.36 (11)	C4—C5—H5	121.6
C2—C1—Cl1	118.22 (11)	C6—C5—H5	121.6
N2—C2—C3	120.88 (13)	C1—C6—C5	120.38 (13)
N2—C2—C1	121.98 (13)	C1—C6—H6	119.8
C3—C2—C1	117.09 (13)	C5—C6—H6	119.8
C6—C1—C2—N2	−177.05 (13)	N1—C4—C5—C6	−179.64 (12)
Cl1—C1—C2—N2	3.57 (17)	C2—C1—C6—C5	0.2 (2)
C6—C1—C2—C3	0.33 (19)	Cl1—C1—C6—C5	179.57 (10)
Cl1—C1—C2—C3	−179.04 (9)	C4—C5—C6—C1	−0.5 (2)
N2—C2—C3—C4	176.87 (12)	C3—C4—N1—O1	−5.21 (19)
C1—C2—C3—C4	−0.55 (19)	C5—C4—N1—O1	174.73 (13)
C2—C3—C4—C5	0.2 (2)	C3—C4—N1—O2	174.29 (13)
C2—C3—C4—N1	−179.82 (12)	C5—C4—N1—O2	−5.8 (2)
C3—C4—C5—C6	0.3 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···O1^i	0.85 (2)	2.33 (2)	3.1521 (18)	163.2 (19)
N2—H2B···N2^ii	0.88 (3)	2.44 (2)	3.1452 (19)	137.4 (18)

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