A redetermination of 4-chloro-3-nitro­benzoic acid

In the title compound, C₇H₄ClNO₄, the mol­ecules form centrosymmetric dimers through O—H...O hydrogen bonds. The dimers are connected by C—H...O hydrogen bonds to form molecular tapes. Disorder of the H atom in the O—H...O hydrogen bond is suggested.

Key indicators

• Single-crystal X-ray study
• T = 297 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.033
• wR factor = 0.087
• Data-to-parameter ratio = 13.4

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT052_ALERT_1_A (Proper) Absorption Correction Method Missing ..          ?

Alert level B
PLAT222_ALERT_3_B Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       4.66 Ratio

Author Response: see _publ_section_comment

Alert level C
PLAT057_ALERT_3_C Correction for Absorption Required   RT(exp)   =       1.15
PLAT355_ALERT_3_C Long    O-H Bond (0.82A)   O2     -   H4       =       1.04 Ang.
PLAT417_ALERT_2_C Short Inter D-H..H-D       H4     ..  H4       =       2.10 Ang.

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

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1990); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: TEXSAN for Windows (Molecular Structure Corporation, 1997-1999); program(s) used to solve structure: SIR92 (Altomare et al. 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: TEXSAN for Windows.

(I)

Crystal data

C7H4ClNO4	F(000) = 408.00
Mr = 201.57	Dx = 1.694 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 25 reflections
a = 7.404 (3) Å	θ = 11.8–12.4°
b = 5.6695 (9) Å	µ = 0.46 mm^−1
c = 19.144 (3) Å	T = 297 K
β = 100.42 (2)°	Prismatic, colorless
V = 790.4 (4) Å^3	0.50 × 0.45 × 0.20 mm
Z = 4

Data collection

Rigaku AFC-5R diffractometer	1458 reflections with I > 2σ(I)
Radiation source: Rigaku rotating anode	Rint = 0.011
Graphite monochromator	θmax = 27.5°, θmin = 2.2°
ω–2θ scans	h = −1→9
Absorption correction: ψ scan (North et al., 1968)	k = 0→7
Tmin = 0.839, Tmax = 0.914	l = −24→24
2234 measured reflections	3 standard reflections every 97 reflections
1815 independent reflections	intensity decay: 3.3%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.033	All H-atom parameters refined
wR(F^2) = 0.087	w = 1/[σ^2(Fo^2) + (0.0175P)^2 + 0.37P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max = 0.001
1815 reflections	Δρmax = 0.27 e Å^−3
135 parameters	Δρmin = −0.19 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 constraints	Extinction coefficient: 0.022 (2)

Special details

Experimental. The scan width was (1.68 + 0.30tanθ)° with an ω scan speed of 6° per minute (up to 3 scans to achieve I/σ(I) > 10). Stationary background counts were recorded at each end of the scan, and the scan time:background time ratio was 2:1.

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
Cl	−0.10139 (7)	0.37469 (9)	0.68248 (3)	0.04677 (17)
O1	0.28058 (19)	−0.4635 (3)	0.51224 (8)	0.0511 (4)
O2	0.52851 (18)	−0.2484 (3)	0.55339 (8)	0.0499 (4)
O3	0.4487 (2)	0.4707 (3)	0.69530 (8)	0.0578 (4)
O4	0.2740 (2)	0.3787 (3)	0.77033 (8)	0.0562 (4)
N	0.3218 (2)	0.3616 (3)	0.71286 (8)	0.0383 (4)
C1	0.2472 (2)	−0.1339 (3)	0.58417 (9)	0.0322 (4)
C2	0.3319 (2)	0.0424 (3)	0.62893 (9)	0.0318 (4)
C3	0.2254 (2)	0.1895 (3)	0.66192 (9)	0.0311 (4)
C4	0.0348 (2)	0.1732 (3)	0.64910 (9)	0.0322 (4)
C5	−0.0482 (2)	−0.0042 (3)	0.60515 (10)	0.0372 (4)
C6	0.0570 (3)	−0.1580 (3)	0.57377 (10)	0.0369 (4)
C7	0.3579 (2)	−0.2939 (3)	0.54748 (9)	0.0354 (4)
H1	0.458 (3)	0.065 (3)	0.6390 (10)	0.035 (5)*
H2	−0.179 (3)	−0.016 (4)	0.5960 (11)	0.049 (6)*
H3	0.001 (3)	−0.277 (4)	0.5440 (10)	0.043 (6)*
H4	0.592 (6)	−0.377 (7)	0.528 (2)	0.163 (17)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl	0.0395 (3)	0.0464 (3)	0.0569 (3)	0.0088 (2)	0.0154 (2)	−0.0081 (2)
O1	0.0406 (7)	0.0521 (8)	0.0612 (9)	−0.0039 (7)	0.0105 (7)	−0.0268 (7)
O2	0.0350 (7)	0.0506 (9)	0.0665 (9)	−0.0040 (6)	0.0157 (6)	−0.0220 (7)
O3	0.0561 (9)	0.0504 (9)	0.0658 (10)	−0.0214 (7)	0.0082 (8)	−0.0084 (7)
O4	0.0517 (8)	0.0719 (11)	0.0453 (8)	−0.0004 (8)	0.0097 (7)	−0.0244 (8)
N	0.0347 (8)	0.0341 (8)	0.0440 (9)	0.0018 (7)	0.0016 (6)	−0.0072 (7)
C1	0.0326 (8)	0.0328 (9)	0.0315 (8)	0.0007 (7)	0.0062 (7)	−0.0020 (7)
C2	0.0278 (8)	0.0331 (9)	0.0343 (9)	0.0004 (7)	0.0048 (7)	−0.0016 (7)
C3	0.0326 (8)	0.0296 (8)	0.0303 (8)	−0.0011 (7)	0.0039 (7)	−0.0010 (7)
C4	0.0327 (8)	0.0325 (9)	0.0331 (8)	0.0037 (7)	0.0107 (7)	0.0019 (7)
C5	0.0277 (8)	0.0440 (10)	0.0402 (10)	−0.0032 (8)	0.0070 (7)	−0.0030 (8)
C6	0.0348 (9)	0.0385 (10)	0.0374 (9)	−0.0064 (8)	0.0064 (7)	−0.0071 (8)
C7	0.0335 (9)	0.0371 (9)	0.0353 (9)	0.0008 (7)	0.0052 (7)	−0.0047 (7)

Geometric parameters (Å, º)

Cl—C4	1.7215 (18)	C2—C3	1.377 (2)
C7—O1	1.252 (2)	C3—C4	1.391 (2)
C7—O2	1.274 (2)	C4—C5	1.382 (3)
N—O3	1.222 (2)	C5—C6	1.378 (3)
N—O4	1.219 (2)	C2—H1	0.93 (2)
N—C3	1.470 (2)	C5—H2	0.95 (2)
C1—C2	1.390 (2)	C6—H3	0.93 (2)
C1—C6	1.392 (3)	O2—H4	1.04 (4)
C1—C7	1.482 (2)
Cl···O4^i	3.282 (2)	O3···C7^iv	3.091 (3)
Cl···O4^ii	3.321 (2)	O3···O4^v	3.084 (3)
O1···O2^iii	2.624 (2)	O4···C5^ii	3.219 (3)
O3···C1^iv	3.260 (3)	C6···C6^vi	3.322 (3)
O1—C7—O2	123.54 (17)	C2—C3—C4	121.70 (16)
O1—C7—C1	119.15 (16)	C2—C3—N	117.19 (15)
O2—C7—C1	117.30 (16)	C4—C3—N	121.09 (15)
C7—O2—H4	110 (2)	C5—C4—C3	118.77 (16)
O4—N—O3	124.85 (16)	C5—C4—Cl	118.86 (14)
O4—N—C3	117.80 (16)	C3—C4—Cl	122.29 (14)
O3—N—C3	117.29 (15)	C6—C5—C4	120.10 (17)
C2—C1—C6	119.38 (16)	C6—C5—H2	120.7 (13)
C2—C1—C7	120.37 (16)	C4—C5—H2	119.2 (13)
C6—C1—C7	120.25 (16)	C5—C6—C1	120.83 (17)
C3—C2—C1	119.10 (16)	C5—C6—H3	120.2 (13)
C3—C2—H1	117.4 (12)	C1—C6—H3	119.0 (13)
C1—C2—H1	123.5 (12)
C6—C1—C2—C3	−0.1 (3)	N—C3—C4—Cl	8.5 (2)
C7—C1—C2—C3	179.55 (16)	C3—C4—C5—C6	−1.3 (3)
C1—C2—C3—C4	−3.0 (3)	Cl—C4—C5—C6	175.54 (14)
C1—C2—C3—N	175.53 (15)	C4—C5—C6—C1	−1.7 (3)
O4—N—C3—C2	−132.61 (18)	C2—C1—C6—C5	2.4 (3)
O3—N—C3—C2	44.7 (2)	C7—C1—C6—C5	−177.20 (17)
O4—N—C3—C4	45.9 (2)	C2—C1—C7—O1	174.02 (17)
O3—N—C3—C4	−136.79 (18)	C6—C1—C7—O1	−6.3 (3)
C2—C3—C4—C5	3.7 (3)	C2—C1—C7—O2	−6.5 (3)
N—C3—C4—C5	−174.78 (16)	C6—C1—C7—O2	173.11 (18)
C2—C3—C4—Cl	−173.02 (14)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H4···O1^iii	1.04 (4)	1.60 (4)	2.624 (2)	169 (4)
C5—H2···O2^vii	0.95 (2)	2.54 (2)	3.406 (3)	150.8 (18)

Symmetry codes: (iii) −x+1, −y−1, −z+1; (vii) x−1, y, z.