2,6-Di­bromo-4-methyl­aniline

The mol­ecules of the title compound are linked by weak N—H⋯N hydrogen bonds into [100] chains.

Abstract

In the title compound, C₇H₇Br₂N, the C—C—C bond angles of the benzene ring are notably distorted and two short intamolecular N—H⋯Br contacts occur. In the crystal, the mol­ecules are linked by N—H⋯N hydrogen bonds to generate C(2) chains propagating in the [100] direction.

Structure description

The solid-state structure of the title compound, C₇H₇Br₂N, was established by single-crystal X-ray diffraction analysis at 200 K and the mol­ecular structure is illustrated in Fig. 1 ▸. The bromine atoms are slightly displaced from the mean plane of C1–C4/C6/C7 benzene ring, by 0.032 (1) and 0.065 (1) Å for Br1 and Br2, respectively. This can also be qu­anti­fied by the C4—C3—C2—Br1 and C4—C6—C7—Br2 torsion angles, which are 179.7 (3) and −178.5 (3)°, respectively. The bond angles in the benzene ring are notably distorted from the ideal value of 120° with C7—C1—C2 = 115.1 (4), C1—C2—C3 = 122.8 (4) and C1—C7—C6 = 123.0 (4)°. The amine group lying between the bromine atoms results in two short intra­molecular N—H⋯Br contacts (Table 1 ▸).

Figure 1.

The mol­ecular structure of the title compound showing displacement ellipsoids at the 50% probability level.

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯Br1	0.86	2.65	3.077 (4)	112
N1—H1B⋯Br2	0.86	2.64	3.072 (4)	113
N1—H1B⋯N1i	0.86	2.38	3.120 (7)	144

Symmetry code: (i) .

In the crystal, the mol­ecules are linked by weak N1—H1B⋯N1 hydrogen bonds (Table 1 ▸) with N⋯N = 3.120 (7) Å to generate [100] C(2) chains with adjacent mol­ecules related by the 2₁ screw axis. A similar hydrogen bond was observed in di­amino­mesithylene (Brihi et al., 2016 ▸). The packing is illustrated in Fig. 2 ▸, which shows the topology of the chain is a zigzag, with an angle of inclination of the benzene ring to the a axis of 53.73 (14)°.

Figure 2.

Views along the (a) b and (b) c axes of the crystal packing of the title compound with hydrogen bonds shown as dotted lines.

Synthesis and crystallization

The title compound is commercially available (Lancaster Synthesis). It was purified by recrystallization from a solution of 80% ethanol and 20% distilled water. The colorless single crystals obtained are in the form of needles, which grow along the a axis.

Refinement

Crystal data, data collection and structure refinement details of the compound are summarized in Table 2 ▸.

Table 2. Experimental details.

Crystal data
Chemical formula	C7H7Br2N
M r	264.96
Crystal system, space group	Orthorhombic, P212121
Temperature (K)	200
a, b, c (Å)	4.3773 (7), 13.585 (2), 14.057 (3)
V (Å3)	835.9 (2)
Z	4
Radiation type	Mo Kα
μ (mm−1)	9.62
Crystal size (mm)	0.12 × 0.05 × 0.04
Data collection
Diffractometer	Bruker APEXII QUAZAR CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2016 ▸)
T min, T max	0.396, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	7550, 1715, 1422
R int	0.061
(sin θ/λ)max (Å−1)	0.626
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.030, 0.072, 0.91
No. of reflections	1715
No. of parameters	92
H-atom treatment	H-atom parameters not refined
Δρmax, Δρmin (e Å−3)	0.36, −0.38
Absolute structure	Flack (1983 ▸)
Absolute structure parameter	0.02 (2)

Computer programs: APEX2 and SAINT (Bruker, 2016 ▸), SIR92 (Altomare et al., 1994 ▸), SHELXL2013 (Sheldrick, 2015 ▸), ORTEP for Windows and WinGX publication routines (Farrugia, 2012 ▸).

Supplementary Material

CCDC reference: 2175519

Additional supporting information: crystallographic information; 3D view; checkCIF report

full crystallographic data

Crystal data

C7H7Br2N	F(000) = 504
Mr = 264.96	Dx = 2.105 Mg m−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 7750 reflections
a = 4.3773 (7) Å	θ = 2.1–26.4°
b = 13.585 (2) Å	µ = 9.62 mm−1
c = 14.057 (3) Å	T = 200 K
V = 835.9 (2) Å3	Needle, colorless
Z = 4	0.12 × 0.05 × 0.04 mm

Data collection

Bruker APEXII QUAZAR CCD diffractometer	1715 independent reflections
Radiation source: ImuS	1422 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.061
Detector resolution: 8.02 pixels mm-1	θmax = 26.4°, θmin = 2.1°
f\ and ω scans	h = −5→5
Absorption correction: multi-scan (SADABS; Bruker, 2016)	k = −15→16
Tmin = 0.396, Tmax = 0.746	l = −17→17
7550 measured reflections

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.030	H-atom parameters not refined
wR(F2) = 0.072	w = 1/[σ2(Fo2) + (0.0409P)2] where P = (Fo2 + 2Fc2)/3
S = 0.91	(Δ/σ)max = 0.001
1715 reflections	Δρmax = 0.36 e Å−3
92 parameters	Δρmin = −0.38 e Å−3
0 restraints	Absolute structure: Flack (1983)
0 constraints	Absolute structure parameter: 0.02 (2)
Primary atom site location: structure-invariant direct methods

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles

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 > 2sigma(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
Br1	0.69454 (12)	0.51851 (3)	0.40790 (4)	0.0449 (2)
Br2	0.49325 (11)	0.11063 (3)	0.35184 (3)	0.0374 (2)
N1	0.4343 (8)	0.3124 (3)	0.4488 (2)	0.0340 (14)
C1	0.6072 (9)	0.3165 (3)	0.3674 (3)	0.0255 (14)
C2	0.7481 (9)	0.4015 (3)	0.3360 (3)	0.0277 (14)
C3	0.9295 (10)	0.4045 (3)	0.2553 (3)	0.0323 (17)
C4	0.9781 (10)	0.3217 (3)	0.2004 (3)	0.0313 (14)
C5	1.1658 (11)	0.3259 (3)	0.1108 (3)	0.0447 (17)
C6	0.8409 (10)	0.2336 (3)	0.2315 (3)	0.0317 (14)
C7	0.6636 (10)	0.2322 (3)	0.3118 (3)	0.0280 (12)
H1	1.33755	0.28238	0.11654	0.0669*
H1A	0.40957	0.36443	0.48284	0.0407*
H1B	0.35064	0.25790	0.46576	0.0407*
H2	1.02080	0.46361	0.23780	0.0388*
H3	0.87095	0.17585	0.19722	0.0378*
H4	1.23699	0.39194	0.10090	0.0669*
H5	1.04240	0.30603	0.05765	0.0669*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Br1	0.0576 (3)	0.0274 (2)	0.0497 (3)	−0.0005 (2)	0.0057 (3)	−0.0016 (2)
Br2	0.0373 (3)	0.0279 (2)	0.0471 (3)	−0.0053 (2)	−0.0027 (3)	0.0002 (2)
N1	0.038 (3)	0.031 (2)	0.033 (2)	−0.0013 (18)	0.0070 (18)	0.0005 (17)
C1	0.0174 (19)	0.028 (2)	0.031 (3)	0.0015 (17)	−0.0052 (19)	0.007 (2)
C2	0.023 (2)	0.027 (2)	0.033 (3)	0.0023 (18)	−0.0039 (19)	0.0002 (19)
C3	0.027 (3)	0.029 (3)	0.041 (3)	0.0011 (19)	0.001 (2)	0.006 (2)
C4	0.021 (2)	0.041 (3)	0.032 (2)	0.005 (2)	0.000 (2)	0.007 (2)
C5	0.036 (3)	0.057 (3)	0.041 (3)	0.009 (3)	0.005 (3)	0.008 (3)
C6	0.030 (2)	0.038 (3)	0.027 (2)	0.004 (2)	−0.004 (2)	−0.002 (2)
C7	0.024 (2)	0.028 (2)	0.032 (2)	0.001 (2)	−0.006 (2)	−0.0010 (19)

Geometric parameters (Å, º)

Br1—C2	1.898 (4)	C4—C5	1.505 (6)
Br2—C7	1.898 (4)	C4—C6	1.409 (6)
N1—C1	1.373 (5)	C6—C7	1.370 (6)
N1—H1A	0.8600	C3—H2	0.9300
N1—H1B	0.8600	C5—H1	0.9600
C1—C7	1.408 (6)	C5—H4	0.9600
C1—C2	1.382 (6)	C5—H5	0.9600
C2—C3	1.385 (6)	C6—H3	0.9300
C3—C4	1.381 (6)
C1—N1—H1B	120.00	Br2—C7—C1	118.3 (3)
H1A—N1—H1B	120.00	Br2—C7—C6	118.6 (3)
C1—N1—H1A	120.00	C1—C7—C6	123.0 (4)
C2—C1—C7	115.1 (4)	C2—C3—H2	119.00
N1—C1—C7	121.8 (4)	C4—C3—H2	119.00
N1—C1—C2	123.1 (4)	C4—C5—H1	110.00
Br1—C2—C1	118.3 (3)	C4—C5—H4	110.00
Br1—C2—C3	118.8 (3)	C4—C5—H5	109.00
C1—C2—C3	122.8 (4)	H1—C5—H4	109.00
C2—C3—C4	121.5 (4)	H1—C5—H5	109.00
C5—C4—C6	121.7 (4)	H4—C5—H5	109.00
C3—C4—C5	121.4 (4)	C4—C6—H3	120.00
C3—C4—C6	116.9 (4)	C7—C6—H3	120.00
C4—C6—C7	120.6 (4)
N1—C1—C2—Br1	−1.0 (5)	Br1—C2—C3—C4	179.7 (3)
N1—C1—C2—C3	178.1 (4)	C1—C2—C3—C4	0.6 (7)
C7—C1—C2—Br1	−178.5 (3)	C2—C3—C4—C5	177.7 (4)
C7—C1—C2—C3	0.6 (6)	C2—C3—C4—C6	−1.5 (6)
N1—C1—C7—Br2	0.1 (6)	C3—C4—C6—C7	1.2 (6)
N1—C1—C7—C6	−178.5 (4)	C5—C4—C6—C7	−178.1 (4)
C2—C1—C7—Br2	177.6 (3)	C4—C6—C7—Br2	−178.5 (3)
C2—C1—C7—C6	−1.0 (6)	C4—C6—C7—C1	0.1 (7)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···Br1	0.86	2.65	3.077 (4)	112
N1—H1B···Br2	0.86	2.64	3.072 (4)	113
N1—H1B···N1i	0.86	2.38	3.120 (7)	144

Symmetry code: (i) x−1/2, −y+1/2, −z+1.