2-Nitro-anilinium bromide.

The title compound, C(6)H(7)N(2)O(2) (+)·Br(-), is isomorphous with 2-nitro-anilinium chloride and contains an characteristic intra-molecular N-H⋯O hydrogen bond, forming an S(6) motif. Inter-molecular N-H⋯Br hydrogen bonds occur in the crystal structure. Two zigzag chains of C(2) (1)(4) motifs extend along the b-axis direction. These primary chain motifs inter-sect like a double helix structure, leading to R(6) (3)(12) ring motifs, which are arranged in tandem along the b axis. Hence, hydro-philic layers are generated at z = 1/4 and 3/4, which are sandwiched between alternate hydro-phobic layers across z = 0 and 1/2.

Related literature

For related structures, see: Herbstein (1965 ▶); Dhaneshwar et al. (1978 ▶); Saminathan & Sivakumar (2007 ▶); Ploug-Sørensen & Andersen (1983) ▶. For hydrogen-bonding motifs, see: Bernstein et al. (1995 ▶); Desiraju (1989 ▶).

Experimental

Crystal data

C6H7N2O2 +·Br−

M = 219.05

Orthorhombic,

a = 8.0268 (8) Å

b = 8.1242 (7) Å

c = 23.7912 (19) Å

V = 1551.5 (2) Å3

Z = 8

Mo Kα radiation

μ = 5.25 mm−1

T = 293 K

0.21 × 0.19 × 0.17 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer

12000 measured reflections

1372 independent reflections

1107 reflections with I > 2σ(I)

R int = 0.085

Refinement

R[F 2 > 2σ(F 2)] = 0.031

wR(F 2) = 0.076

S = 0.96

1372 reflections

112 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.74 e Å−3

Δρmin = −0.38 e Å−3

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL/PC (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL/PC; molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXTL/PC.

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811041948/ff2032sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811041948/ff2032Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536811041948/ff2032Isup3.cml

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

C6H7N2O2+·Br−	F(000) = 864
Mr = 219.05	Dx = 1.876 Mg m−3Dm = 1.86 (1) Mg m−3Dm measured by Flotation technique using a liquid-mixture of carbon tetrachloride and bromoform
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 2610 reflections
a = 8.0268 (8) Å	θ = 2.6–24.6°
b = 8.1242 (7) Å	µ = 5.25 mm−1
c = 23.7912 (19) Å	T = 293 K
V = 1551.5 (2) Å3	Block, colourless
Z = 8	0.21 × 0.19 × 0.17 mm

Bruker SMART APEX CCD area-detector diffractometer	1107 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.085
graphite	θmax = 25.0°, θmin = 1.7°
ω scans	h = −9→9
12000 measured reflections	k = −9→9
1372 independent reflections	l = −28→28

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)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.076	H atoms treated by a mixture of independent and constrained refinement
S = 0.96	w = 1/[σ2(Fo2) + (0.046P)2] where P = (Fo2 + 2Fc2)/3
1372 reflections	(Δ/σ)max = 0.001
112 parameters	Δρmax = 0.74 e Å−3
0 restraints	Δρmin = −0.38 e Å−3

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.

	x	y	z	Uiso*/Ueq
Br1	0.79124 (4)	0.19991 (4)	0.286284 (13)	0.04040 (17)
C1	0.8664 (4)	0.5387 (3)	0.09113 (11)	0.0305 (7)
C2	0.8275 (3)	0.4633 (3)	0.14194 (11)	0.0282 (7)
C3	0.6626 (4)	0.4451 (4)	0.15682 (13)	0.0348 (7)
H3	0.6347	0.3967	0.1910	0.042*
C4	0.5389 (4)	0.4989 (5)	0.12095 (13)	0.0432 (8)
H4	0.4276	0.4834	0.1305	0.052*
C5	0.5790 (4)	0.5754 (4)	0.07105 (13)	0.0462 (9)
H5	0.4948	0.6128	0.0474	0.055*
C6	0.7426 (4)	0.5965 (4)	0.05606 (13)	0.0410 (8)
H6	0.7698	0.6493	0.0226	0.049*
N2	0.9543 (4)	0.4115 (4)	0.18231 (12)	0.0329 (6)
N1	1.0379 (4)	0.5526 (3)	0.07159 (10)	0.0399 (7)
O1	1.1385 (3)	0.4512 (3)	0.08824 (9)	0.0533 (7)
O2	1.0721 (3)	0.6593 (3)	0.03787 (11)	0.0675 (8)
H1N	1.020 (4)	0.348 (4)	0.1700 (14)	0.040 (11)*
H2N	1.020 (7)	0.494 (6)	0.1982 (18)	0.100 (16)*
H3N	0.902 (6)	0.351 (5)	0.2156 (15)	0.070 (12)*

	U11	U22	U33	U12	U13	U23
Br1	0.0387 (2)	0.0383 (2)	0.0443 (3)	0.00825 (15)	0.00844 (14)	0.00908 (14)
C1	0.0328 (16)	0.0321 (17)	0.0266 (16)	0.0011 (14)	0.0013 (13)	−0.0034 (12)
C2	0.0276 (15)	0.0292 (16)	0.0277 (16)	0.0021 (12)	−0.0041 (12)	−0.0039 (12)
C3	0.0304 (16)	0.0439 (19)	0.0300 (16)	−0.0013 (15)	0.0029 (13)	−0.0014 (14)
C4	0.0295 (17)	0.058 (2)	0.0422 (19)	0.0049 (17)	−0.0016 (15)	−0.0075 (17)
C5	0.041 (2)	0.058 (2)	0.0395 (18)	0.0158 (17)	−0.0142 (15)	−0.0036 (17)
C6	0.050 (2)	0.0449 (19)	0.0280 (17)	0.0063 (17)	−0.0044 (14)	0.0035 (14)
N2	0.0288 (15)	0.0392 (16)	0.0306 (15)	−0.0038 (15)	−0.0048 (12)	0.0051 (14)
N1	0.0394 (16)	0.0507 (18)	0.0296 (14)	−0.0036 (15)	0.0023 (12)	−0.0026 (13)
O1	0.0339 (13)	0.0780 (19)	0.0481 (14)	0.0083 (13)	0.0047 (11)	0.0051 (13)
O2	0.0715 (19)	0.0676 (16)	0.0635 (17)	−0.0107 (16)	0.0210 (14)	0.0255 (14)

C1—C6	1.380 (4)	C5—C6	1.372 (5)
C1—C2	1.391 (4)	C5—H5	0.9300
C1—N1	1.458 (4)	C6—H6	0.9300
C2—C3	1.378 (4)	N2—H1N	0.79 (3)
C2—N2	1.461 (4)	N2—H2N	0.93 (6)
C3—C4	1.380 (4)	N2—H3N	1.02 (4)
C3—H3	0.9300	N1—O2	1.213 (3)
C4—C5	1.378 (5)	N1—O1	1.220 (3)
C4—H4	0.9300
C6—C1—C2	120.9 (3)	C4—C5—H5	119.9
C6—C1—N1	117.5 (3)	C5—C6—C1	119.3 (3)
C2—C1—N1	121.6 (3)	C5—C6—H6	120.3
C3—C2—C1	119.1 (3)	C1—C6—H6	120.3
C3—C2—N2	118.0 (3)	C2—N2—H1N	114 (2)
C1—C2—N2	122.8 (3)	C2—N2—H2N	117 (3)
C2—C3—C4	119.9 (3)	H1N—N2—H2N	103 (4)
C2—C3—H3	120.1	C2—N2—H3N	111 (2)
C4—C3—H3	120.1	H1N—N2—H3N	104 (3)
C5—C4—C3	120.5 (3)	H2N—N2—H3N	106 (3)
C5—C4—H4	119.8	O2—N1—O1	123.2 (3)
C3—C4—H4	119.8	O2—N1—C1	118.7 (3)
C6—C5—C4	120.3 (3)	O1—N1—C1	118.0 (3)
C6—C5—H5	119.9
C6—C1—C2—C3	0.7 (4)	C4—C5—C6—C1	0.7 (5)
N1—C1—C2—C3	−176.3 (3)	C2—C1—C6—C5	−1.6 (5)
C6—C1—C2—N2	−175.3 (3)	N1—C1—C6—C5	175.5 (3)
N1—C1—C2—N2	7.8 (4)	C6—C1—N1—O2	25.6 (4)
C1—C2—C3—C4	1.1 (5)	C2—C1—N1—O2	−157.3 (3)
N2—C2—C3—C4	177.3 (3)	C6—C1—N1—O1	−151.2 (3)
C2—C3—C4—C5	−2.0 (5)	C2—C1—N1—O1	25.9 (4)
C3—C4—C5—C6	1.1 (5)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H1N···O1	0.79 (3)	2.32 (3)	2.702 (4)	111 (3)
N2—H1N···Br1i	0.79 (3)	2.70 (4)	3.291 (3)	133 (3)
N2—H2N···Br1ii	0.93 (6)	2.29 (6)	3.197 (3)	165 (4)
N2—H3N···Br1	1.02 (4)	2.26 (4)	3.284 (3)	176 (3)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H1N⋯O1	0.79 (3)	2.32 (3)	2.702 (4)	111 (3)
N2—H1N⋯Br1i	0.79 (3)	2.70 (4)	3.291 (3)	133 (3)
N2—H2N⋯Br1ii	0.93 (6)	2.29 (6)	3.197 (3)	165 (4)
N2—H3N⋯Br1	1.02 (4)	2.26 (4)	3.284 (3)	176 (3)

Symmetry codes: (i) ; (ii) .