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ISSN: 2414-3146

A monoclinic polymorph of 2-(4-nitro­phen­yl)acetic acid

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aWestChem, Department of Pure & Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, Scotland
*Correspondence e-mail: a.r.kennedy@strath.ac.uk

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 19 November 2016; accepted 2 December 2016; online 9 December 2016)

A new monoclinic form of 4-nitro­phenyl­acetic acid, C8H7NO4, (I), differs from the known ortho­rhom­bic form both in its mol­ecular conformation and in its inter­molecular contacts. The conformation is different as the plane of the carb­oxy­lic acid group in (I) is more nearly perpendicular to the plane of the aromatic ring [dihedral angle = 86.9 (3)°] than in the previous form (74.5°). Both polymorphs display hydrogen-bonded R22(8) carb­oxy­lic acid dimeric pairs, but in (I), neighbouring dimers inter­act through nitro–nitro N⋯O dipole–dipole contacts rather than the nitro–carbonyl contacts found in the ortho­rhom­bic form.

3D view (loading...)
[Scheme 3D1]
Chemical scheme
[Scheme 1]

Structure description

An ortho­rhom­bic polymorph of 4-nitro­phenyl­acetic acid was crystallized from ethanol solution and structurally described by Grabowski et al. (1990[Grabowski, S. J., Krygowski, T. M., Häfelinger, G. & Ritter, G. (1990). Acta Cryst. C46, 428-430.]). The new polymorph described herein, (I), features a mol­ecular structure with a nitro group that is essentially coplanar with the aromatic ring [dihedral angle = 3.9 (3) °] and a carb­oxy­lic acid group that approaches the perpendicular with respect to the aromatic ring [dihedral angle = 86.9 (3)°], see Fig. 1[link]. The previously known ortho­rhom­bic polymorph also features near coplanarity of the nitro and aromatic groups, but the carb­oxy­lic acid group lies further from the perpendicular (74.5°).

[Figure 1]
Figure 1
The mol­ecular structure of (I). Displacement ellipsoids are drawn at the 50% probability level.

In the crystal structure of (I), strong O—H⋯O hydrogen bonds (Table 1[link]) occur between carb­oxy­lic acid groups, creating the classic dimeric [R_{2}^{2}](8) motif (Fig. 2[link]). This motif is also present in the ortho­rhom­bic polymorph. A difference is that in (I) these dimers inter­connect through nitro-to-nitro dipole-to-dipole contacts [O3⋯N1ii 2.923 (3) Å, symmetry code: (ii) 2 − x, −[{1\over 2}] + y, [{1\over 2}] − z] to form an extended chain (Wozniak et al., 1994[Wozniak, K., He, H., Klinowski, J., Jones, W. & Grech, E. (1994). J. Phys. Chem. 98, 13755-13765.]). However, in the ortho­rhom­bic form of 4-nitro­phenyl­acetic acid, the nitro group forms nitro-to-carbonyl dipole–dipole contacts instead. A similar set of inter­molecular contacts to that found in (I) is found in the polymorph of 4-nitro­benzoic acid described by Groth (1980[Groth, P. (1980). Acta Chem. Scand. Ser. A, 34, 229-230.]). Inter­estingly, that structure also has a unit cell that is similar to that found for (I) (a = 5.403, b = 5.153, c = 24.692 Å, β = 96.89°, space group P21/c).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O2—H2O⋯O1i 0.99 (4) 1.69 (4) 2.672 (2) 170 (3)
Symmetry code: (i) -x, -y+1, -z.
[Figure 2]
Figure 2
The crystal structure of (I) displays the classic [R_{2}^{2}](8) carb­oxy­lic acid dimeric hydrogen-bonding motif. Neighbouring dimers inter­act through nitro-to-nitro contacts to form a chain.

Synthesis and crystallization

The crystallization of 4-nitro­phenyl­acetic acid occurred during an attempt to synthesize a salt form of N-methyl­ephedrine by reaction with the acid (Kennedy et al., 2011[Kennedy, A. R., Morrison, C. A., Briggs, N. E. B. & Arbuckle, W. (2011). Cryst. Growth Des. 11, 1821-1834.]): 1.27 mmol of 4-nitro­phenyl­acetic acid was dissolved in 5 ml of deionized water and the added to a slurry of 1 mmol of base in 5 ml of deionized water. The resulting solution was stirred at 323 K for 30 minutes and filtered. The solution was then put into a test tube and left to slowly evaporate and to cool to room temperature: monoclinic 4-nitro­phenyl­acetic acid in the form of colourless tablets crystallized on the walls of the test tube.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link].

Table 2
Experimental details

Crystal data
Chemical formula C8H7NO4
Mr 181.15
Crystal system, space group Monoclinic, P21/c
Temperature (K) 150
a, b, c (Å) 6.1364 (5), 5.1034 (4), 25.458 (3)
β (°) 95.937 (8)
V3) 792.98 (13)
Z 4
Radiation type Mo Kα
μ (mm−1) 0.12
Crystal size (mm) 0.32 × 0.18 × 0.13
 
Data collection
Diffractometer Oxford Diffraction Xcalibur Eos
Absorption correction Multi-scan CrysAlis PRO (Agilent, 2014[Agilent (2014). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.])
Tmin, Tmax 0.880, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections 15530, 1814, 1076
Rint 0.090
(sin θ/λ)max−1) 0.650
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.054, 0.130, 1.06
No. of reflections 1814
No. of parameters 122
H-atom treatment H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.24, −0.26
Computer programs: CrysAlis PRO (Agilent, 2014[Agilent (2014). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.]), SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL2014 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), ORTEP-3 for Windows (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]) and Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.]).

Structural data


Computing details top

Data collection: CrysAlis PRO (Agilent, 2014); cell refinement: CrysAlis PRO (Agilent, 2014); data reduction: CrysAlis PRO (Agilent, 2014); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015).

2-(4-Nitrophenyl)acetic acid top
Crystal data top
C8H7NO4F(000) = 376
Mr = 181.15Dx = 1.517 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 6.1364 (5) ÅCell parameters from 2414 reflections
b = 5.1034 (4) Åθ = 3.2–28.7°
c = 25.458 (3) ŵ = 0.12 mm1
β = 95.937 (8)°T = 150 K
V = 792.98 (13) Å3Tablet, colourless
Z = 40.32 × 0.18 × 0.13 mm
Data collection top
Oxford Diffraction Xcalibur Eos
diffractometer
1814 independent reflections
Radiation source: Enhance (Mo) X-ray Source1076 reflections with I > 2σ(I)
Detector resolution: 16.0727 pixels mm-1Rint = 0.090
ω scansθmax = 27.5°, θmin = 3.2°
Absorption correction: multi-scan
CrysAlis PRO (Agilent, 2014)
h = 77
Tmin = 0.880, Tmax = 1.000k = 66
15530 measured reflectionsl = 3332
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.054H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.130 w = 1/[σ2(Fo2) + (0.0414P)2 + 0.2348P]
where P = (Fo2 + 2Fc2)/3
S = 1.06(Δ/σ)max < 0.001
1814 reflectionsΔρmax = 0.24 e Å3
122 parametersΔρmin = 0.26 e Å3
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O20.1037 (3)0.8022 (4)0.03062 (7)0.0364 (5)
O30.8335 (3)0.2053 (3)0.23833 (7)0.0349 (5)
O41.0830 (3)0.1662 (4)0.18470 (7)0.0371 (5)
O10.2209 (3)0.3888 (3)0.03653 (7)0.0337 (5)
N10.9081 (3)0.1028 (4)0.20049 (8)0.0274 (5)
C40.7826 (4)0.1092 (5)0.17228 (9)0.0229 (5)
C10.5454 (4)0.5029 (5)0.11899 (9)0.0243 (6)
C60.4753 (4)0.3949 (5)0.16427 (9)0.0267 (6)
H60.34490.45820.17700.032*
C80.2380 (4)0.6189 (5)0.04973 (9)0.0252 (6)
C50.5924 (4)0.1965 (5)0.19118 (9)0.0265 (6)
H50.54310.12180.22200.032*
C30.8571 (4)0.2132 (5)0.12774 (9)0.0288 (6)
H30.98860.15110.11550.035*
C20.7366 (4)0.4104 (5)0.10109 (10)0.0297 (6)
H20.78580.48330.07010.036*
C70.4160 (4)0.7176 (5)0.08958 (10)0.0284 (6)
H7A0.34970.82980.11540.034*
H7B0.51730.82800.07130.034*
H2O0.009 (7)0.741 (8)0.0027 (16)0.099 (13)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O20.0362 (11)0.0257 (10)0.0427 (11)0.0049 (9)0.0178 (9)0.0012 (9)
O30.0359 (11)0.0336 (11)0.0346 (10)0.0010 (9)0.0003 (8)0.0081 (9)
O40.0291 (10)0.0390 (12)0.0430 (11)0.0141 (9)0.0033 (8)0.0006 (9)
O10.0353 (11)0.0213 (10)0.0416 (11)0.0006 (8)0.0095 (8)0.0026 (8)
N10.0262 (12)0.0240 (12)0.0307 (12)0.0026 (10)0.0032 (9)0.0034 (10)
C40.0213 (12)0.0217 (13)0.0242 (13)0.0034 (11)0.0050 (9)0.0015 (11)
C10.0237 (13)0.0225 (13)0.0250 (13)0.0016 (11)0.0056 (10)0.0032 (10)
C60.0236 (13)0.0296 (14)0.0264 (13)0.0053 (11)0.0005 (10)0.0038 (11)
C80.0250 (14)0.0241 (14)0.0260 (13)0.0009 (11)0.0008 (10)0.0032 (11)
C50.0276 (13)0.0268 (13)0.0251 (13)0.0008 (12)0.0021 (10)0.0004 (11)
C30.0214 (13)0.0337 (15)0.0315 (14)0.0054 (12)0.0038 (10)0.0002 (12)
C20.0264 (14)0.0349 (15)0.0277 (14)0.0013 (12)0.0026 (11)0.0045 (12)
C70.0277 (14)0.0244 (13)0.0309 (14)0.0004 (11)0.0071 (11)0.0026 (11)
Geometric parameters (Å, º) top
O2—C81.307 (3)C1—C71.506 (3)
O2—H2O0.99 (4)C6—C51.382 (3)
O3—N11.226 (3)C6—H60.9500
O4—N11.228 (2)C8—C71.499 (3)
O1—C81.223 (3)C5—H50.9500
N1—C41.472 (3)C3—C21.384 (3)
C4—C31.372 (3)C3—H30.9500
C4—C51.382 (3)C2—H20.9500
C1—C21.385 (3)C7—H7A0.9900
C1—C61.386 (3)C7—H7B0.9900
C8—O2—H2O114 (2)C6—C5—C4118.6 (2)
O3—N1—O4123.7 (2)C6—C5—H5120.7
O3—N1—C4118.6 (2)C4—C5—H5120.7
O4—N1—C4117.7 (2)C4—C3—C2118.7 (2)
C3—C4—C5121.9 (2)C4—C3—H3120.7
C3—C4—N1119.0 (2)C2—C3—H3120.7
C5—C4—N1119.1 (2)C3—C2—C1120.9 (2)
C2—C1—C6119.0 (2)C3—C2—H2119.5
C2—C1—C7120.4 (2)C1—C2—H2119.5
C6—C1—C7120.6 (2)C8—C7—C1113.7 (2)
C5—C6—C1120.9 (2)C8—C7—H7A108.8
C5—C6—H6119.6C1—C7—H7A108.8
C1—C6—H6119.6C8—C7—H7B108.8
O1—C8—O2123.5 (2)C1—C7—H7B108.8
O1—C8—C7123.0 (2)H7A—C7—H7B107.7
O2—C8—C7113.5 (2)
O3—N1—C4—C3175.6 (2)C5—C4—C3—C20.3 (4)
O4—N1—C4—C34.7 (3)N1—C4—C3—C2179.2 (2)
O3—N1—C4—C53.9 (3)C4—C3—C2—C10.4 (4)
O4—N1—C4—C5175.8 (2)C6—C1—C2—C30.0 (4)
C2—C1—C6—C50.5 (4)C7—C1—C2—C3180.0 (2)
C7—C1—C6—C5179.5 (2)O1—C8—C7—C110.7 (3)
C1—C6—C5—C40.6 (4)O2—C8—C7—C1169.3 (2)
C3—C4—C5—C60.2 (4)C2—C1—C7—C893.1 (3)
N1—C4—C5—C6179.7 (2)C6—C1—C7—C886.9 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2O···O1i0.99 (4)1.69 (4)2.672 (2)170 (3)
Symmetry code: (i) x, y+1, z.
 

Acknowledgements

The financial support of a PhD studentship by CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnol­ogici) and the advice of GSK are gratefully acknowledged.

References

First citationAgilent (2014). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.  Google Scholar
First citationFarrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationGrabowski, S. J., Krygowski, T. M., Häfelinger, G. & Ritter, G. (1990). Acta Cryst. C46, 428–430.  CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationGroth, P. (1980). Acta Chem. Scand. Ser. A, 34, 229–230.  CrossRef Web of Science Google Scholar
First citationKennedy, A. R., Morrison, C. A., Briggs, N. E. B. & Arbuckle, W. (2011). Cryst. Growth Des. 11, 1821–1834.  Web of Science CSD CrossRef CAS Google Scholar
First citationMacrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationWozniak, K., He, H., Klinowski, J., Jones, W. & Grech, E. (1994). J. Phys. Chem. 98, 13755–13765.  CrossRef CAS Web of Science Google Scholar

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