p-Nitro­aniline hydro­bromide

The crystal stucture of p-nitro­aniline hydro­bromide, C₆H₇N₂O₂⁺·Br⁻ or O₂NC₆H₄NH₃⁺·Br⁻, exhibits ionic layers separated by hydro­carbon layers. The hydro­carbon layers stack head-to-tail but no π–π inter­actions are observed. In the inorganic layer, the ammonium group, Br⁻ anion and nitro group inter­act to form a three-dimensional hydrogen-bonded network. The structure is compared with that of the related compound O₂NC₆H₄NH₃⁺·Cl⁻.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.024
• wR factor = 0.056
• Data-to-parameter ratio = 12.4

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT199_ALERT_1_C Check the Reported _cell_measurement_temperature        293 K
PLAT380_ALERT_4_C Check Incorrectly? Oriented X(sp2)-Methyl Moiety         N2

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           25.49
           From the CIF: _reflns_number_total               1254
           Count of symmetry unique reflns          829
           Completeness (_total/calc)            151.27%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       425
           Fraction of Friedel pairs measured     0.513
           Are heavy atom types Z>Si present        yes

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

   1 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
   2 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: SMART-NT (Bruker (1998); cell refinement: SMART-NT; data reduction: SAINT-Plus (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 1999); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2003).

p-Nitroaniline hydrobromide

Crystal data

C6H7N2O2^+·Br^−	F(000) = 1728
Mr = 219.05	Dx = 1.827 Mg m^−3
Orthorhombic, Fdd2	Mo Kα radiation, λ = 0.71069 Å
Hall symbol: F 2 -2d	Cell parameters from 898 reflections
a = 20.625 (5) Å	θ = 3.3–26.9°
b = 30.408 (5) Å	µ = 5.11 mm^−1
c = 5.080 (5) Å	T = 293 K
V = 3186 (3) Å^3	Needle, green
Z = 16	0.4 × 0.21 × 0.04 mm

Data collection

Bruker SMART CCD area-detector diffractometer	1157 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.036
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	θmax = 25.5°, θmin = 2.4°
Tmin = 0.290, Tmax = 0.810	h = −24→24
4378 measured reflections	k = −36→30
1254 independent reflections	l = −6→5

Refinement

Refinement on F^2	H-atom parameters constrained
Least-squares matrix: full	w = 1/[σ^2(Fo^2) + 2.6422P] where P = (Fo^2 + 2Fc^2)/3
R[F^2 > 2σ(F^2)] = 0.024	(Δ/σ)max < 0.001
wR(F^2) = 0.056	Δρmax = 0.31 e Å^−3
S = 1.08	Δρmin = −0.29 e Å^−3
1254 reflections	Absolute structure: Flack (1983), 425 Friedel pairs
101 parameters	Absolute structure parameter: 0.022 (16)
1 restraint

Special details

Experimental. absorption corrections were made using the program SADABS (Sheldrick, 1996).

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.39716 (15)	0.25556 (12)	0.1947 (8)	0.0316 (9)
C2	0.35624 (17)	0.25214 (11)	0.4062 (9)	0.0370 (9)
H2	0.3539	0.2262	0.5029	0.044*
C3	0.31829 (17)	0.28829 (13)	0.4732 (8)	0.0377 (9)
H3	0.289	0.2868	0.612	0.045*
C4	0.32510 (15)	0.32612 (12)	0.3302 (8)	0.0281 (9)
C5	0.36652 (15)	0.32939 (11)	0.1168 (9)	0.0339 (7)
H5	0.3694	0.3554	0.0217	0.041*
C6	0.40326 (17)	0.29348 (13)	0.0476 (7)	0.0347 (9)
H6	0.4315	0.2947	−0.0948	0.042*
N1	0.43751 (14)	0.21729 (10)	0.1249 (13)	0.0413 (7)
N2	0.28665 (15)	0.36505 (10)	0.3998 (9)	0.0397 (7)
H2A	0.2618	0.3589	0.5383	0.06*
H2B	0.2617	0.3726	0.2641	0.06*
H2C	0.3131	0.3872	0.4392	0.06*
O1	0.44171 (14)	0.18736 (10)	0.2833 (7)	0.0549 (9)
O2	0.46439 (14)	0.21709 (10)	−0.0926 (8)	0.0588 (9)
Br1	0.186979 (17)	0.344520 (12)	0.88052 (13)	0.03852 (13)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0266 (17)	0.0278 (19)	0.040 (2)	−0.0006 (14)	−0.0060 (16)	−0.0015 (16)
C2	0.0400 (18)	0.0279 (18)	0.043 (2)	−0.0033 (14)	0.004 (2)	0.0094 (19)
C3	0.039 (2)	0.037 (2)	0.037 (2)	−0.0055 (17)	0.0123 (18)	0.0057 (17)
C4	0.0257 (16)	0.0292 (18)	0.029 (3)	−0.0031 (13)	−0.0006 (16)	0.0005 (16)
C5	0.0369 (17)	0.0313 (18)	0.0337 (19)	−0.0032 (15)	0.004 (2)	0.0081 (18)
C6	0.0295 (17)	0.042 (2)	0.033 (2)	−0.0031 (16)	0.0040 (16)	0.0035 (17)
N1	0.0312 (14)	0.0361 (17)	0.056 (2)	0.0027 (14)	0.0010 (18)	0.004 (3)
N2	0.0449 (16)	0.0351 (17)	0.0391 (19)	0.0017 (13)	0.0080 (19)	0.0010 (18)
O1	0.0561 (18)	0.0418 (19)	0.067 (2)	0.0137 (14)	−0.0062 (15)	0.0100 (17)
O2	0.0550 (17)	0.0518 (19)	0.070 (2)	0.0078 (14)	0.026 (2)	−0.002 (2)
Br1	0.03616 (18)	0.0443 (2)	0.03514 (19)	−0.00076 (15)	0.00584 (18)	−0.00469 (18)

Geometric parameters (Å, º)

C1—C2	1.370 (5)	C5—C6	1.375 (5)
C1—C6	1.380 (5)	C5—H5	0.93
C1—N1	1.474 (5)	C6—H6	0.93
C2—C3	1.392 (5)	N1—O1	1.218 (6)
C2—H2	0.93	N1—O2	1.236 (7)
C3—C4	1.368 (6)	N2—H2A	0.89
C3—H3	0.93	N2—H2B	0.89
C4—C5	1.384 (5)	N2—H2C	0.89
C4—N2	1.468 (5)
C2—C1—C6	123.0 (3)	C4—C5—H5	120.5
C2—C1—N1	118.5 (4)	C5—C6—C1	118.4 (3)
C6—C1—N1	118.6 (4)	C5—C6—H6	120.8
C1—C2—C3	118.6 (3)	C1—C6—H6	120.8
C1—C2—H2	120.7	O1—N1—O2	123.7 (4)
C3—C2—H2	120.7	O1—N1—C1	118.1 (5)
C4—C3—C2	118.5 (4)	O2—N1—C1	118.2 (4)
C4—C3—H3	120.8	C4—N2—H2A	109.5
C2—C3—H3	120.8	C4—N2—H2B	109.5
C3—C4—C5	122.7 (3)	H2A—N2—H2B	109.5
C3—C4—N2	119.6 (3)	C4—N2—H2C	109.5
C5—C4—N2	117.7 (4)	H2A—N2—H2C	109.5
C6—C5—C4	118.9 (3)	H2B—N2—H2C	109.5
C6—C5—H5	120.5
C6—C1—C2—C3	1.1 (6)	C4—C5—C6—C1	0.0 (5)
N1—C1—C2—C3	179.7 (4)	C2—C1—C6—C5	−0.1 (5)
C1—C2—C3—C4	−2.1 (6)	N1—C1—C6—C5	−178.7 (4)
C2—C3—C4—C5	2.2 (6)	C2—C1—N1—O1	−13.0 (5)
C2—C3—C4—N2	−178.8 (4)	C6—C1—N1—O1	165.6 (3)
C3—C4—C5—C6	−1.1 (6)	C2—C1—N1—O2	165.9 (4)
N2—C4—C5—C6	179.8 (4)	C6—C1—N1—O2	−15.4 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···Br1	0.89	2.37	3.253 (4)	174
N2—H2B···O1^i	0.89	2.48	2.915 (5)	110
N2—H2B···Br1^ii	0.89	2.63	3.402 (5)	146
N2—H2C···Br1^iii	0.89	2.79	3.535 (4)	142

Symmetry codes: (i) −x+3/4, y+1/4, z−1/4; (ii) x, y, z−1; (iii) x+1/4, −y+3/4, z−1/4.