2-Amino-3-nitro­benzoic acid

Abstract

The title compound, C₇H₆N₂O₄, is approximately planar (r.m.s. deviation = 0.026 Å for the 13 non-H atoms). The mol­ecular structure is stabilized by intra­molecular N—H⋯O hydrogen bonds, which generate S(6) ring motifs. In the crystal, mol­ecules are linked via inter­molecular N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds into a three-dimensional network.

Related literature

For general background to the title compound and related structures, see: Win et al. (2010 ▶, 2011a ▶,b ▶,c ▶). For standard bond-length data, see: Allen et al. (1987 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For the stability of the temperature controller used in the the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

• C₇H₆N₂O₄

• M _r = 182.14

• Monoclinic,

• a = 9.0231 (3) Å

• b = 7.4338 (2) Å

• c = 11.0392 (4) Å

• β = 92.114 (1)°

• V = 739.96 (4) ų

• Z = 4

• Mo Kα radiation

• μ = 0.14 mm⁻¹

• T = 100 K

• 0.34 × 0.26 × 0.16 mm

Data collection

• Bruker SMART APEXII CCD area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.956, T _max = 0.979

• 22297 measured reflections

• 3247 independent reflections

• 2707 reflections with I > 2σ(I)

• R _int = 0.030

Refinement

• R[F ² > 2σ(F ²)] = 0.042

• wR(F ²) = 0.121

• S = 1.04

• 3247 reflections

• 130 parameters

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 0.55 e Å⁻³

• Δρ_min = −0.33 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Supplementary material file. DOI: 10.1107/S1600536812002036/qm2050Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H1N2⋯O2	0.892 (17)	1.958 (16)	2.6082 (11)	128.5 (13)
N2—H1N2⋯O1i	0.892 (17)	2.499 (17)	3.2885 (12)	147.8 (14)
N2—H2N2⋯O3	0.872 (15)	1.982 (16)	2.6582 (10)	133.4 (14)
O4—H1O4⋯O3ii	0.83 (2)	1.81 (2)	2.6397 (10)	176.2 (17)
C3—H3A⋯O1iii	0.95	2.49	3.4349 (12)	176

Symmetry codes: (i) ; (ii) ; (iii) .

supplementary crystallographic information

Comment

In the study of organotin(IV) carboxylate complexes, 2-amino-5-nitrobenzoic, 2-amino-3-nitrobenzoic, 4-amino-3-nitrobenzoic and 5-amino-2-nitrobenzoic acids have been utilized in the synthesis work (Win et al., 2010, 2011a, 2011b, 2011c). The carboxylate anions of the acids are found to be bonded to tin(IV) atom moieties in both a monodentate and a bidentate manner resulting in structural diversity for organotin(IV) carboxylate complexes (Win et al., 2010, 2011a, 2011b, 2011c).

The title compound, Fig.1, is approximately planar (r.m.s. deviation = 0.026 Å for the 13 non-H atoms). Bond lengths (Allen et al., 1987) and angles are within normal ranges and are comparable to related structures (Win et al., 2010, 2011a, 2011b, 2011c). The molecular structure is stabilized by intramolecular N2–H1N2···O2 and N2–H2N2···O3 hydrogen bonds (Table 1), which generate S(6) ring motifs (Fig. 1, Bernstein et al., 1995).

In the crystal structure, Fig. 2, molecules are linked via intermolecular N2–H1N2···O1, O4–H1O4···O3 and C3–H3A···O1 hydrogen bonds (Table 1) into a three-dimensional network.

Experimental

The attempt to prepare organotin(IV) carboxylate complexes by heating under reflux the mixture of 2-amino-3-nitrobenzoic acid (2 mmol) and dimethyltin(IV) oxide (4 mmol) for 4 h in 50 ml of methanol was unsuccessful. The resulting orange solution was filtered and orange crystals were obtained after 2 weeks. Unfortunately, the crystals obtained were found to be the starting material (2-amino-3-nitrobenzoic acid) with the melting point of 482 K.

Refinement

Atoms H1O4, H1N2 and H2N2 were located in a difference Fourier map and refined freely with O-H = 0.83 (2) Å and N-H = 0.875 (18) and 0.893 (17) Å. The remaining H atoms were positioned geometrically and refined using a riding model with C–H = 0.95 Å and U_iso(H) = 1.2 U_eq(C).

Figures

Fig. 1.

The molecular structure of the title compound showing 50% probability displacement ellipsoids for non-H atoms. Intramolecular hydrogen bonds are shown as dashed lines.

Fig. 2.

The crystal structure of the title compound, viewed along the b axis. H atoms not involved in hydrogen bonds (dashed lines) have been omitted for clarity.

Crystal data

C7H6N2O4	F(000) = 376
Mr = 182.14	Dx = 1.635 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 9956 reflections
a = 9.0231 (3) Å	θ = 2.9–34.8°
b = 7.4338 (2) Å	µ = 0.14 mm−1
c = 11.0392 (4) Å	T = 100 K
β = 92.114 (1)°	Block, orange
V = 739.96 (4) Å3	0.34 × 0.26 × 0.16 mm
Z = 4

Data collection

Bruker SMART APEXII CCD area-detector diffractometer	3247 independent reflections
Radiation source: fine-focus sealed tube	2707 reflections with I > 2σ(I)
graphite	Rint = 0.030
φ and ω scans	θmax = 35.0°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −14→12
Tmin = 0.956, Tmax = 0.979	k = −11→11
22297 measured reflections	l = −17→17

Refinement

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)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.121	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	w = 1/[σ2(Fo2) + (0.0662P)2 + 0.1903P] where P = (Fo2 + 2Fc2)/3
3247 reflections	(Δ/σ)max = 0.001
130 parameters	Δρmax = 0.55 e Å−3
0 restraints	Δρmin = −0.33 e Å−3

Special details

Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
O1	1.00882 (10)	0.85440 (11)	0.40698 (8)	0.03096 (19)
O2	0.99701 (8)	0.61460 (10)	0.29827 (6)	0.02030 (14)
O3	0.62645 (7)	0.11784 (9)	0.43650 (6)	0.01909 (14)
O4	0.51199 (8)	0.18983 (10)	0.60595 (6)	0.01981 (14)
N1	0.95660 (8)	0.70510 (10)	0.38522 (6)	0.01587 (14)
N2	0.81247 (9)	0.35687 (11)	0.34730 (7)	0.01954 (16)
C1	0.64687 (9)	0.51128 (12)	0.62950 (7)	0.01552 (15)
H1A	0.5784	0.4697	0.6865	0.019*
C2	0.71159 (10)	0.67982 (12)	0.64617 (8)	0.01749 (16)
H2A	0.6870	0.7528	0.7131	0.021*
C3	0.81229 (9)	0.73922 (12)	0.56356 (7)	0.01620 (15)
H3A	0.8579	0.8536	0.5742	0.019*
C4	0.84738 (9)	0.63239 (11)	0.46482 (7)	0.01390 (14)
C5	0.78217 (8)	0.45981 (11)	0.44292 (7)	0.01334 (14)
C6	0.67970 (9)	0.40152 (11)	0.53140 (7)	0.01354 (14)
C7	0.60572 (9)	0.22530 (11)	0.51976 (7)	0.01458 (15)
H1N2	0.8797 (19)	0.393 (2)	0.2953 (15)	0.034 (4)*
H2N2	0.7714 (18)	0.251 (2)	0.3400 (14)	0.033 (4)*
H1O4	0.471 (2)	0.092 (3)	0.5901 (16)	0.044 (5)*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.0415 (4)	0.0181 (3)	0.0343 (4)	−0.0153 (3)	0.0144 (3)	−0.0043 (3)
O2	0.0229 (3)	0.0216 (3)	0.0168 (3)	−0.0046 (2)	0.0065 (2)	−0.0007 (2)
O3	0.0214 (3)	0.0154 (3)	0.0210 (3)	−0.0059 (2)	0.0076 (2)	−0.0043 (2)
O4	0.0231 (3)	0.0189 (3)	0.0180 (3)	−0.0087 (2)	0.0080 (2)	−0.0028 (2)
N1	0.0173 (3)	0.0151 (3)	0.0153 (3)	−0.0030 (2)	0.0017 (2)	0.0023 (2)
N2	0.0221 (3)	0.0175 (3)	0.0197 (3)	−0.0068 (3)	0.0094 (3)	−0.0058 (3)
C1	0.0162 (3)	0.0166 (3)	0.0139 (3)	−0.0015 (3)	0.0025 (2)	−0.0015 (3)
C2	0.0198 (3)	0.0165 (4)	0.0163 (3)	−0.0011 (3)	0.0029 (3)	−0.0036 (3)
C3	0.0179 (3)	0.0138 (3)	0.0169 (3)	−0.0013 (3)	0.0008 (3)	−0.0014 (3)
C4	0.0143 (3)	0.0133 (3)	0.0142 (3)	−0.0016 (2)	0.0016 (2)	0.0009 (2)
C5	0.0135 (3)	0.0134 (3)	0.0132 (3)	−0.0007 (2)	0.0019 (2)	−0.0003 (2)
C6	0.0135 (3)	0.0128 (3)	0.0144 (3)	−0.0016 (2)	0.0021 (2)	−0.0007 (2)
C7	0.0143 (3)	0.0145 (3)	0.0151 (3)	−0.0025 (3)	0.0024 (2)	0.0003 (3)

Geometric parameters (Å, °)

O1—N1	1.2260 (10)	C1—C6	1.3964 (11)
O2—N1	1.2380 (10)	C1—H1A	0.9500
O3—C7	1.2371 (10)	C2—C3	1.3832 (12)
O4—C7	1.3227 (10)	C2—H2A	0.9500
O4—H1O4	0.83 (2)	C3—C4	1.3945 (11)
N1—C4	1.4490 (10)	C3—H3A	0.9500
N2—C5	1.3401 (11)	C4—C5	1.4283 (11)
N2—H1N2	0.893 (17)	C5—C6	1.4364 (11)
N2—H2N2	0.875 (18)	C6—C7	1.4737 (11)
C1—C2	1.3916 (12)
C7—O4—H1O4	108.3 (12)	C2—C3—H3A	119.8
O1—N1—O2	121.45 (7)	C4—C3—H3A	119.8
O1—N1—C4	118.94 (7)	C3—C4—C5	122.67 (7)
O2—N1—C4	119.59 (7)	C3—C4—N1	116.15 (7)
C5—N2—H1N2	119.8 (11)	C5—C4—N1	121.17 (7)
C5—N2—H2N2	119.3 (10)	N2—C5—C4	123.47 (7)
H1N2—N2—H2N2	120.7 (15)	N2—C5—C6	121.24 (7)
C2—C1—C6	121.91 (7)	C4—C5—C6	115.30 (7)
C2—C1—H1A	119.0	C1—C6—C5	120.75 (7)
C6—C1—H1A	119.0	C1—C6—C7	118.60 (7)
C3—C2—C1	118.87 (8)	C5—C6—C7	120.64 (7)
C3—C2—H2A	120.6	O3—C7—O4	121.60 (8)
C1—C2—H2A	120.6	O3—C7—C6	123.94 (7)
C2—C3—C4	120.47 (8)	O4—C7—C6	114.46 (7)
C6—C1—C2—C3	−0.58 (13)	N1—C4—C5—C6	177.80 (7)
C1—C2—C3—C4	0.47 (13)	C2—C1—C6—C5	−0.28 (13)
C2—C3—C4—C5	0.49 (13)	C2—C1—C6—C7	−179.61 (8)
C2—C3—C4—N1	−178.63 (8)	N2—C5—C6—C1	−178.81 (8)
O1—N1—C4—C3	−1.42 (12)	C4—C5—C6—C1	1.16 (11)
O2—N1—C4—C3	177.38 (7)	N2—C5—C6—C7	0.50 (13)
O1—N1—C4—C5	179.46 (8)	C4—C5—C6—C7	−179.53 (7)
O2—N1—C4—C5	−1.75 (12)	C1—C6—C7—O3	179.89 (8)
C3—C4—C5—N2	178.69 (8)	C5—C6—C7—O3	0.55 (13)
N1—C4—C5—N2	−2.24 (13)	C1—C6—C7—O4	0.60 (11)
C3—C4—C5—C6	−1.28 (12)	C5—C6—C7—O4	−178.73 (7)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H1N2···O2	0.892 (17)	1.958 (16)	2.6082 (11)	128.5 (13)
N2—H1N2···O1i	0.892 (17)	2.499 (17)	3.2885 (12)	147.8 (14)
N2—H2N2···O3	0.872 (15)	1.982 (16)	2.6582 (10)	133.4 (14)
O4—H1O4···O3ii	0.83 (2)	1.81 (2)	2.6397 (10)	176.2 (17)
C3—H3A···O1iii	0.95	2.49	3.4349 (12)	176

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