3-Nitro­cinnamic acid

The title compound, C₉H₇NO₄, forms centrosymmetric dimers through inter­molecular O—H...O hydrogen bonds in the crystal structure. The nitro group deviates slightly from coplanarity with the benzene ring. The benzene ring and the carboxylic acid group are in an E configuration about the ethyl­enic double bond.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.046
• wR factor = 0.146
• Data-to-parameter ratio = 11.5

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT029_ALERT_3_A _diffrn_measured_fraction_theta_full Low .......       0.93

Author Response: The crystal used for data collection did not diffract well since the available crystal is only one. we tried to recrystallise several times we could not get good crystals.

Alert level C
REFLT03_ALERT_3_C  Reflection count < 95% complete
           From the CIF: _diffrn_reflns_theta_max           67.90
           From the CIF: _diffrn_reflns_theta_full          67.90
           From the CIF: _reflns_number_total               1478
           TEST2: Reflns within _diffrn_reflns_theta_max
           Count of symmetry unique reflns         1595
           Completeness (_total/calc)             92.66%
PLAT022_ALERT_3_C Ratio Unique / Expected Reflections too Low ....       0.93
PLAT199_ALERT_1_C Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_C Check the Reported _diffrn_ambient_temperature .        293 K

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

   2 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
   3 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion


checkCIF publication errors

Alert level A
PUBL023_ALERT_1_A There is a mismatched ^ on line 373
                Refinement of F2^ against ALL reflections.  The weighted R-factor wR and
              If you require a ^ then it should be escaped
              with a \, i.e. \^
              Otherwise there must be a matching closing ~, e.g. ^12^C
PUBL023_ALERT_1_A There is a mismatched ^ on line 374
                goodness of fit S are based on F2^, conventional R-factors R are based
              If you require a ^ then it should be escaped
              with a \, i.e. \^
              Otherwise there must be a matching closing ~, e.g. ^12^C
PUBL023_ALERT_1_A There is a mismatched ^ on line 375
                on F, with F set to zero for negative F2^. The threshold expression of
              If you require a ^ then it should be escaped
              with a \, i.e. \^
              Otherwise there must be a matching closing ~, e.g. ^12^C
PUBL023_ALERT_1_A There is a mismatched ^ on line 378
                on F2^ are statistically about twice as large as those based on F, and R-
              If you require a ^ then it should be escaped
              with a \, i.e. \^
              Otherwise there must be a matching closing ~, e.g. ^12^C
PUBL023_ALERT_1_A There is a mismatched ^ on line 394
                'Fc^*^=kFc[1+0.001xFc^2^\l3^/sin(2\q)]^-1/4^'
              If you require a ^ then it should be escaped
              with a \, i.e. \^
              Otherwise there must be a matching closing ~, e.g. ^12^C

   5 ALERT level A = Data missing that is essential or data in wrong format
   0 ALERT level G = General alerts. Data that may be required is missing

---

Computing details

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: CAD-4 EXPRESS; data reduction: MolEN (Fair, 1990); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003).

3-Nitrocinnamic acid

Crystal data

C9H7NO4	F(000) = 400
Mr = 193.16	Dx = 1.479 Mg m^−3
Monoclinic, P21/n	Cu Kα radiation, λ = 1.54180 Å
Hall symbol: -P 2yn	Cell parameters from 25 reflections
a = 3.7756 (2) Å	θ = 20–30°
b = 9.4584 (13) Å	µ = 1.02 mm^−1
c = 24.295 (4) Å	T = 293 K
β = 90.875 (8)°	Block, colourless
V = 867.52 (18) Å^3	0.30 × 0.20 × 0.20 mm
Z = 4

Data collection

Enraf–Nonius CAD-4 diffractometer	1068 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.043
Graphite monochromator	θmax = 67.9°, θmin = 3.6°
ω–2θ scans	h = 0→4
Absorption correction: ψ scan (North et al., 1968)	k = 0→11
Tmin = 0.751, Tmax = 0.823	l = −29→29
1733 measured reflections	3 standard reflections every 120 min
1478 independent reflections	intensity decay: none

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)] = 0.046	H-atom parameters constrained
wR(F^2) = 0.146	w = 1/[σ^2(Fo^2) + (0.0726P)^2 + 0.3649P] where P = (Fo^2 + 2Fc^2)/3
S = 1.03	(Δ/σ)max < 0.001
1478 reflections	Δρmax = 0.30 e Å^−3
129 parameters	Δρmin = −0.17 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ3^/sin(2^θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0054 (11)

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
C1	0.3333 (6)	0.0198 (2)	0.11430 (10)	0.0508 (6)
C2	0.4539 (6)	0.0178 (2)	0.16858 (9)	0.0465 (6)
H2	0.5548	−0.0636	0.1835	0.056*
C3	0.4216 (6)	0.1376 (2)	0.19963 (9)	0.0458 (6)
C4	0.2784 (7)	0.2620 (2)	0.17952 (12)	0.0592 (7)
H4	0.2600	0.3417	0.2017	0.071*
C5	0.1638 (7)	0.2640 (3)	0.12542 (13)	0.0647 (7)
H5	0.0688	0.3464	0.1105	0.078*
C6	0.1888 (7)	0.1455 (3)	0.09359 (11)	0.0590 (7)
H6	0.1078	0.1485	0.0573	0.071*
N1	0.5488 (6)	0.1356 (2)	0.25715 (9)	0.0559 (6)
C7	0.3562 (7)	−0.1043 (3)	0.07858 (10)	0.0592 (7)
H7	0.2666	−0.0932	0.0430	0.071*
C8	0.4884 (7)	−0.2302 (3)	0.09062 (10)	0.0617 (7)
H8	0.5826	−0.2459	0.1257	0.074*
C9	0.4915 (7)	−0.3454 (3)	0.05071 (10)	0.0565 (6)
O1	0.4837 (7)	0.2370 (2)	0.28617 (9)	0.0890 (7)
O2	0.7153 (6)	0.0337 (2)	0.27319 (8)	0.0752 (6)
O9	0.3566 (5)	−0.3298 (2)	0.00408 (7)	0.0708 (6)
O10	0.6367 (6)	−0.4602 (2)	0.06723 (8)	0.0758 (6)
H10	0.6165	−0.5206	0.0432	0.091*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0513 (15)	0.0489 (13)	0.0521 (14)	−0.0067 (10)	−0.0025 (10)	0.0060 (10)
C2	0.0461 (14)	0.0402 (11)	0.0532 (13)	−0.0004 (9)	−0.0019 (10)	0.0055 (9)
C3	0.0377 (13)	0.0433 (11)	0.0566 (14)	−0.0042 (9)	−0.0004 (9)	0.0035 (10)
C4	0.0521 (16)	0.0417 (12)	0.0839 (18)	0.0026 (10)	0.0022 (12)	0.0023 (12)
C5	0.0520 (16)	0.0522 (15)	0.090 (2)	0.0072 (12)	−0.0055 (13)	0.0202 (14)
C6	0.0511 (15)	0.0638 (15)	0.0619 (15)	−0.0048 (12)	−0.0097 (11)	0.0187 (12)
N1	0.0601 (13)	0.0491 (11)	0.0585 (12)	−0.0081 (10)	−0.0017 (9)	−0.0044 (10)
C7	0.0640 (17)	0.0630 (16)	0.0503 (14)	−0.0031 (12)	−0.0064 (12)	0.0052 (11)
C8	0.0758 (19)	0.0599 (15)	0.0492 (14)	0.0023 (13)	−0.0067 (12)	0.0024 (11)
C9	0.0694 (17)	0.0544 (14)	0.0456 (13)	−0.0013 (12)	−0.0018 (11)	0.0014 (11)
O1	0.1182 (18)	0.0708 (13)	0.0777 (14)	0.0059 (12)	−0.0096 (12)	−0.0275 (11)
O2	0.0967 (16)	0.0674 (12)	0.0611 (12)	0.0120 (11)	−0.0161 (10)	0.0039 (9)
O9	0.0944 (15)	0.0670 (12)	0.0504 (10)	0.0113 (10)	−0.0157 (9)	0.0000 (8)
O10	0.1078 (16)	0.0607 (11)	0.0582 (11)	0.0143 (11)	−0.0221 (10)	−0.0038 (8)

Geometric parameters (Å, º)

C1—C2	1.389 (3)	C6—H6	0.9300
C1—C6	1.398 (3)	N1—O2	1.211 (3)
C1—C7	1.463 (3)	N1—O1	1.218 (3)
C2—C3	1.368 (3)	C7—C8	1.323 (3)
C2—H2	0.9300	C7—H7	0.9300
C3—C4	1.381 (3)	C8—C9	1.459 (3)
C3—N1	1.471 (3)	C8—H8	0.9300
C4—C5	1.378 (4)	C9—O9	1.244 (3)
C4—H4	0.9300	C9—O10	1.278 (3)
C5—C6	1.366 (4)	O10—H10	0.8200
C5—H5	0.9300
C2—C1—C6	118.3 (2)	C5—C6—H6	119.2
C2—C1—C7	122.1 (2)	C1—C6—H6	119.2
C6—C1—C7	119.7 (2)	O2—N1—O1	123.3 (2)
C3—C2—C1	118.8 (2)	O2—N1—C3	118.4 (2)
C3—C2—H2	120.6	O1—N1—C3	118.3 (2)
C1—C2—H2	120.6	C8—C7—C1	128.1 (2)
C2—C3—C4	123.3 (2)	C8—C7—H7	116.0
C2—C3—N1	118.86 (19)	C1—C7—H7	116.0
C4—C3—N1	117.9 (2)	C7—C8—C9	122.2 (2)
C5—C4—C3	117.7 (2)	C7—C8—H8	118.9
C5—C4—H4	121.2	C9—C8—H8	118.9
C3—C4—H4	121.2	O9—C9—O10	123.7 (2)
C6—C5—C4	120.4 (2)	O9—C9—C8	120.6 (2)
C6—C5—H5	119.8	O10—C9—C8	115.7 (2)
C4—C5—H5	119.8	C9—O10—H10	109.5
C5—C6—C1	121.6 (2)
C6—C1—C2—C3	1.0 (3)	C2—C3—N1—O2	8.6 (3)
C7—C1—C2—C3	−179.6 (2)	C4—C3—N1—O2	−170.7 (2)
C1—C2—C3—C4	−0.9 (4)	C2—C3—N1—O1	−172.0 (2)
C1—C2—C3—N1	179.9 (2)	C4—C3—N1—O1	8.8 (3)
C2—C3—C4—C5	0.0 (4)	C2—C1—C7—C8	−0.6 (4)
N1—C3—C4—C5	179.2 (2)	C6—C1—C7—C8	178.9 (3)
C3—C4—C5—C6	0.8 (4)	C1—C7—C8—C9	179.5 (2)
C4—C5—C6—C1	−0.7 (4)	C7—C8—C9—O9	−2.5 (4)
C2—C1—C6—C5	−0.2 (4)	C7—C8—C9—O10	178.0 (3)
C7—C1—C6—C5	−179.7 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O10—H10···O9^i	0.82	1.83	2.636 (3)	169

Symmetry code: (i) −x+1, −y−1, −z.