3-Bromo­pyridin-2-amine

In the crystal structure of the title compound, C₅H₅BrN₂, mol­ecules assemble via pairs of N—H⋯N hydrogen bonds into inversion dimers using only the syn H atom on the amine group. These dimers then assemble further into two-dimensional layers via type I C—Br⋯Br [Br⋯Br = 3.693 (s6) Å] halogen bonding along the (102) plane.

Related literature

For halogen bonding, see: Metrangelo et al. (2005). For a related structure, see: Hu et al. (2011).

Experimental

Crystal data

• C₅H₅BrN₂

• M_r = 173.02

• Monoclinic, P 2₁ /c

• a = 12.2179 (6) Å

• b = 4.0007 (2) Å

• c = 12.8451 (6) Å

• β = 109.731 (3)°

• V = 591.01 (5) ų

• Z = 4

• Mo Kα radiation

• μ = 6.84 mm⁻¹

• T = 173 K

• 0.5 × 0.4 × 0.09 mm

Data collection

• Bruker SMART APEXII CCD area-detector diffractometer

• Absorption correction: integration (XPREP; Bruker, 2004) T_min = 0.131, T_max = 0.578

• 5622 measured reflections

• 1428 independent reflections

• 1200 reflections with I > 2σ(I)

• R_int = 0.093

Refinement

• R[F² > 2σ(F²)] = 0.034

• wR(F²) = 0.082

• S = 0.99

• 1428 reflections

• 81 parameters

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 1.04 e Å⁻³

• Δρ_min = −0.77 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2S⋯N1^i	0.81 (4)	2.21 (4)	3.019 (4)	173 (3)
Symmetry code: (i) -x+2, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT-Plus (Bruker, 2004); data reduction: SAINT-Plus and XPREP (Bruker 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); 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, 2009).

Supporting information

S1. Comment

The title compound is being used as a co-crystal former for potential co-crystal with the molecule 2-chloro-4-nitrobenzoic acid. As its structure has not been determined previously, and for screening purposes, it is now reported (Fig. 1). The title molecule forms centrosymmetric dimers using the syn H2S atom on the amine group. The anti H atom H2A is not involved in any intermolecular interactions. The dimers are joined by type II C—Br···Br halogen bonding (Metrangelo et al., 2005) to form 2-D layers (Fig. 2). The related compound, 3-chloropyridin-2-amine (Hu et al., 2011), has the same hydrogen bonded dimers, but forms instead chains of dimers through C—Cl···Cl halogen bonding of type I.

Related literature

For halogen bonding, see: Metrangelo et al. (2005). For a related structure, see: Hu et al. (2011).

S2. Experimental

Crystals were grown by slow evaporation of a methanol solution of the title compound, 0.200 g (1.16 mmol) in 8 ml of methanol, and afforded light brown plates after three days of slow evaporation at ambient conditions.

S3. Refinement

The aromatic C-bound H atoms were geometrically placed, C—H bond length of 0.95 Å and refined as riding with U_iso(H) = 1.2U_eq(C). The N-bound H atoms were located in the difference map and coordinates as well as isotropic displacement parameters refined freely.

Computing details

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT-Plus (Bruker, 2004); data reduction: SAINT-Plus and XPREP (Bruker 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); 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, 2009).

Figures

	Fig. 1. The asymmetric unit of (I) showing the atomic numbering scheme. Displacement ellipsoids are shown at the 50% probability level.
	Fig. 2. Packing diagram of (I). Intermolecular N—H···N hydrogen bonds are shown as dashed red lines forming dimers. Note that the anti H is not used in any hydrogen bonding interactions. The C—Br···Br halogen bonds are shown as dashed blue lines.

3-Bromopyridin-2-amine

Crystal data

C5H5BrN2	F(000) = 336
Mr = 173.02	Dx = 1.945 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2888 reflections
a = 12.2179 (6) Å	θ = 3.2–28.3°
b = 4.0007 (2) Å	µ = 6.84 mm^−1
c = 12.8451 (6) Å	T = 173 K
β = 109.731 (3)°	Plate, brown
V = 591.01 (5) Å^3	0.5 × 0.4 × 0.09 mm
Z = 4

Data collection

Bruker SMART APEXII CCD area-detector diffractometer	1200 reflections with I > 2σ(I)
ω scans	Rint = 0.093
Absorption correction: integration (XPREP; Bruker, 2004)	θmax = 28.0°, θmin = 1.8°
Tmin = 0.131, Tmax = 0.578	h = −16→15
5622 measured reflections	k = −5→5
1428 independent reflections	l = −16→16

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.034	w = 1/[σ^2(Fo^2) + (0.0479P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.082	(Δ/σ)max < 0.001
S = 0.99	Δρmax = 1.04 e Å^−3
1428 reflections	Δρmin = −0.77 e Å^−3
81 parameters

Special details

Experimental. Numerical integration absorption corrections based on indexed crystal faces were applied using the XPREP routine (Bruker, 2004)

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
C2	0.8182 (2)	0.4235 (7)	0.4926 (2)	0.0288 (6)
C3	0.7048 (2)	0.3668 (6)	0.4912 (2)	0.0267 (5)
C4	0.6702 (2)	0.4704 (7)	0.5771 (2)	0.0309 (6)
H4	0.5934	0.4287	0.5763	0.037*
C5	0.7499 (3)	0.6374 (7)	0.6653 (2)	0.0327 (6)
H5	0.729	0.7168	0.7258	0.039*
C6	0.8602 (3)	0.6833 (7)	0.6615 (2)	0.0334 (6)
H6	0.915	0.7976	0.7215	0.04*
N1	0.8956 (2)	0.5781 (6)	0.5793 (2)	0.0325 (5)
N2	0.8547 (3)	0.3359 (7)	0.4077 (2)	0.0386 (6)
Br1	0.59557 (2)	0.15619 (6)	0.36599 (2)	0.03201 (13)
H2S	0.923 (3)	0.345 (7)	0.415 (3)	0.030 (9)*
H2A	0.820 (4)	0.210 (8)	0.362 (4)	0.043 (11)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C2	0.0309 (14)	0.0294 (12)	0.0253 (12)	0.0002 (11)	0.0084 (11)	0.0031 (10)
C3	0.0271 (14)	0.0256 (12)	0.0238 (12)	0.0031 (9)	0.0039 (11)	0.0034 (9)
C4	0.0282 (14)	0.0331 (13)	0.0319 (13)	0.0070 (11)	0.0107 (11)	0.0076 (12)
C5	0.0359 (16)	0.0376 (15)	0.0250 (13)	0.0059 (11)	0.0109 (12)	0.0036 (10)
C6	0.0343 (16)	0.0367 (15)	0.0273 (13)	−0.0010 (12)	0.0079 (12)	0.0002 (11)
N1	0.0286 (13)	0.0408 (12)	0.0266 (11)	−0.0041 (10)	0.0073 (10)	−0.0022 (10)
N2	0.0303 (15)	0.0568 (18)	0.0309 (13)	−0.0112 (12)	0.0134 (12)	−0.0120 (12)
Br1	0.02548 (18)	0.03463 (19)	0.03161 (18)	0.00029 (10)	0.00396 (12)	−0.00178 (10)

Geometric parameters (Å, º)

C2—N1	1.344 (4)	C5—C6	1.378 (5)
C2—N2	1.357 (4)	C5—H5	0.95
C2—C3	1.398 (4)	C6—N1	1.336 (4)
C3—C4	1.372 (4)	C6—H6	0.95
C3—Br1	1.904 (3)	N2—H2S	0.81 (4)
C4—C5	1.390 (4)	N2—H2A	0.78 (4)
C4—H4	0.95
N1—C2—N2	117.1 (3)	C6—C5—H5	121.3
N1—C2—C3	120.2 (2)	C4—C5—H5	121.3
N2—C2—C3	122.7 (3)	N1—C6—C5	124.6 (3)
C4—C3—C2	120.8 (3)	N1—C6—H6	117.7
C4—C3—Br1	119.7 (2)	C5—C6—H6	117.7
C2—C3—Br1	119.5 (2)	C6—N1—C2	118.4 (2)
C3—C4—C5	118.7 (3)	C2—N2—H2S	120 (3)
C3—C4—H4	120.6	C2—N2—H2A	122 (3)
C5—C4—H4	120.6	H2S—N2—H2A	113 (4)
C6—C5—C4	117.3 (3)
N1—C2—C3—C4	0.7 (4)	C3—C4—C5—C6	−1.1 (4)
N2—C2—C3—C4	−177.6 (3)	C4—C5—C6—N1	−0.1 (4)
N1—C2—C3—Br1	178.6 (2)	C5—C6—N1—C2	1.7 (4)
N2—C2—C3—Br1	0.3 (4)	N2—C2—N1—C6	176.5 (3)
C2—C3—C4—C5	0.9 (4)	C3—C2—N1—C6	−1.9 (4)
Br1—C3—C4—C5	−177.04 (19)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2S···N1^i	0.81 (4)	2.21 (4)	3.019 (4)	173 (3)

Symmetry code: (i) −x+2, −y+1, −z+1.