Crystal structure of 2-bromo­benzoic acid at 120 K: a redetermination

The crystal structure of the title compound, C₇H₅BrO₂, was originally studied using photographic data at room temperature with Cu Kα radiation [Ferguson & Sim (1962). Acta Cryst. 15, 346–350]. The present study was undertaken at 120 K with a CCD diffractometer using Cu Kα radiation, and resulted in improved geometrical parameters. In the mol­ecule, the carb­oxy group is inclined to the benzene ring by 18.7 (2)° and there is a close intra­molecular Br⋯O contact of 3.009 (3) Å. In the crystal, mol­ecules are linked by pairs of O—H⋯O hydrogen bonds, forming inversion dimers with the classical R₂²(8) ring motif for carb­oxy­lic acids. Neighbouring dimers are linked by weak C—H⋯O hydrogen bonds, forming tapes propagating in [1-10]. Adjacent tapes inter­act by slipped parallel π–π inter­actions [inter-centroid distance = 3.991 (2), inter­planar distance = 3.509 (2) Å, slippage = 1.900 Å] to form columns approximately along the b-axis direction. Neighbouring columns inter­act dispersively, forming a three-dimensional framework structure.

1. Related literature

For the original report of the unit-cell dimensions, space group and structure of the title compound, see: Ferguson & Sim (1962). For uses of the title compound in organic synthesis, see: Evano et al. (2008); Wolf et al. (2006), and for its physicochemical properties, see: Govindarajan et al. (2011); Sabbah & Aguilar (1996); Swaminathan et al. (2009). For related structures involving the title compound, see: Das et al. (2012); Wales et al. (2012). For reports on Br⋯O inter­actions, see: Jones & Lozano (2004); Saeed et al. (2013); Singh et al. (2009).

2. Experimental

2.1. Crystal data

• C₇H₅BrO₂

• M_r = 201.01

• Monoclinic, C 2/c

• a = 14.7955 (4) Å

• b = 3.99062 (15) Å

• c = 22.9240 (8) Å

• β = 96.906 (3)°

• V = 1343.69 (8) ų

• Z = 8

• Cu Kα radiation

• μ = 7.76 mm⁻¹

• T = 120 K

• 0.55 × 0.35 × 0.28 mm

2.2. Data collection

• Oxford Diffraction Gemini R Ultra Ruby CCD diffractometer

• Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2008) T_min = 0.722, T_max = 0.991

• 10883 measured reflections

• 1201 independent reflections

• 1172 reflections with I > 2σ(I)

• R_int = 0.067

2.3. Refinement

• R[F² > 2σ(F²)] = 0.035

• wR(F²) = 0.091

• S = 1.18

• 1201 reflections

• 95 parameters

• 1 restraint

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

• Δρ_max = 0.82 e Å⁻³

• Δρ_min = −0.52 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O9—H9⋯O8^i	0.81 (3)	1.84 (3)	2.643 (3)	177 (5)
C5—H5⋯O8^ii	0.93	2.65	3.514 (3)	153
C6—H6⋯O9^iii	0.93	2.64	3.417 (3)	141
Symmetry codes: (i) -x+1, -y+1, -z+1; (ii) ; (iii) .

Data collection: CrysAlis CCD (Oxford Diffraction, 2008); cell refinement: CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPII (Burnett & Johnson, 1976); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009).

Supporting information

S1. Comment

2-Bromobenzoic acid is a reagent widely used in organic synthesis, for example in cross-coupling reactions (Evano et al., 2008; Wolf et al., 2006). The physicochemical properties of title compound, such as thermodynamic (Sabbah & Aguilar, 1996) and spectroscopic (Govindarajan et al., 2011; Swaminathan et al., 2009) properties, were studied in literature. In 1962, Ferguson and Sim (Ferguson & Sim, 1962) determined the crystal structure of the title compound (a = 14.82 Å, b = 4.10 Å, c = 25.90 Å, β = 118.26°, V = 1386.2 ų, R = 13.20 %), using photographic data at room temperature. Redetermination of the crystal structure of 2-bromobenzoic acid at 120 K shows, that the unit cell dimensions (see: Experimental section) differs from those reported previously.

The bond lengths and angles characterizing the geometry of molecule of the title compound (Fig. 1) are similar to those found in other structures containing 2-bromobenzoic acid (Das et al., 2012; Wales et al., 2012). The benzene ring makes an angle of 18.7 (2) ° with the mean plane of the carboxy group. There is also a close intramolecular Br10···O8 contact [3.009 (3) Å; as shown in Fig. 1].

In the crystal, molecules are linked into inversion R₂²(8) dimers by pairs of O9–H9···O8ⁱ hydrogen bonds (Table 1 and Fig. 2). Neighbouring dimers are linked by C5–H5···O8ⁱⁱ and C6–H6···O9ⁱⁱⁱ interactions to produce tapes along [1 -1 0] (Table 1 and Fig. 2). Adjacent tapes interact by weak π–π interactions [Cg···Cg^iv = 3.991 (2) Å; Cg is the centroid of the benzene ring C1-C6; interplanar distances = 3.509 (2) Å; slippage 1.900 Å; symmetry code: (iv) x, y-1, z] to form stacked columns approximately along the b-axis (Fig. 3). The neighbouring columns interact dispersively to form a three-dimensional framework structure (Fig. 3).

Related literature

For the original report of the unit-cell dimensions, space group and structure of the title compound, see: Ferguson & Sim (1962). For uses of the title compound in organic synthesis, see: Evano et al. (2008); Wolf et al. (2006), and for its physicochemical properties, see: Govindarajan et al. (2011); Sabbah & Aguilar (1996); Swaminathan et al. (2009). For related structures involving the title compound, see: Das et al. (2012); Wales et al. (2012). For reports on Br···O interactions, see: Jones & Lozano (2004); Saeed et al. (2013); Singh et al. (2009).

S2. Experimental

The 2-bromobenzoic acid was purchased from Sigma Aldrich and used without further purification. The single crystals suitable for X-ray investigations were grown by means of slow evaporation of a mixture of ethanol and water (1:1; v:v) solution (m.p. 422.6).

S3. Refinement

The OH H-atom was located in a difference Fourier map and refined with a distance restraint: O-H = 0.82 (2) Å. The C-bound H atoms were positioned geometrically and constrained to ride on their parent atoms: C–H = 0.93 Å with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2008); cell refinement: CrysAlis CCD (Oxford Diffraction, 2008); data reduction: CrysAlis RED (Oxford Diffraction, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPII (Burnett & Johnson, 1976); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures

	Fig. 1. The molecular structure of the title molecule, with atom labeling. Displacement ellipsoids are drawn at the 25% probability level. The short intramolecular Br···O contact [3.009 (3) Å] is shown as a dashed line.
	Fig. 2. A partial view perpendicular to the ac plane of the crystal packing of the title compound. The O–H···O and C–H···O hydrogen bonds are represented by dashed lines [see Table 1 for details; symmetry codes: (i) –x+1, –y+1, –z+1; (ii) x–1/2, y+1/2, z; (iii) –x+1/2, –y + 3/2, –z+1].
	Fig. 3. A view along the b axis of the crystal packing of the title compound. The π–π interactions are represented by dashed lines [symmetry code: (iv) x, y+1, z].

2-Bromobenzoic acid

Crystal data

C7H5BrO2	F(000) = 784
Mr = 201.01	Dx = 1.987 Mg m^−3
Monoclinic, C2/c	Melting point: 422.6 K
Hall symbol: -C 2yc	Cu Kα radiation, λ = 1.54184 Å
a = 14.7955 (4) Å	Cell parameters from 10883 reflections
b = 3.99062 (15) Å	θ = 3.9–67.3°
c = 22.9240 (8) Å	µ = 7.76 mm^−1
β = 96.906 (3)°	T = 120 K
V = 1343.69 (8) Å^3	Block, white
Z = 8	0.55 × 0.35 × 0.28 mm

Data collection

Oxford Diffraction Gemini R Ultra Ruby CCD diffractometer	1201 independent reflections
Radiation source: fine-focus sealed tube	1172 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.067
Detector resolution: 10.4002 pixels mm^-1	θmax = 67.3°, θmin = 3.9°
ω scans	h = −17→17
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2008)	k = −4→4
Tmin = 0.722, Tmax = 0.991	l = −27→27
10883 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.035	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.091	H atoms treated by a mixture of independent and constrained refinement
S = 1.18	w = 1/[σ^2(Fo^2) + (0.048P)^2 + 4.6943P] where P = (Fo^2 + 2Fc^2)/3
1201 reflections	(Δ/σ)max < 0.001
95 parameters	Δρmax = 0.82 e Å^−3
1 restraint	Δρmin = −0.52 e Å^−3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 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
C1	0.3119 (2)	0.3168 (9)	0.40413 (14)	0.0222 (7)
C2	0.3109 (2)	0.1534 (9)	0.34999 (14)	0.0230 (7)
C3	0.2293 (2)	0.0629 (9)	0.31713 (16)	0.0268 (8)
H3	0.2296	−0.0469	0.2814	0.032*
C4	0.1473 (2)	0.1375 (10)	0.33802 (16)	0.0297 (8)
H4	0.0927	0.0740	0.3164	0.036*
C5	0.1463 (2)	0.3045 (10)	0.39040 (15)	0.0277 (8)
H5	0.0912	0.3580	0.4038	0.033*
C6	0.2278 (2)	0.3931 (10)	0.42318 (15)	0.0265 (8)
H6	0.2266	0.5057	0.4586	0.032*
C7	0.3963 (2)	0.4020 (9)	0.44374 (15)	0.0243 (7)
O8	0.47061 (15)	0.2776 (8)	0.44031 (11)	0.0337 (6)
O9	0.38191 (16)	0.6217 (8)	0.48460 (11)	0.0315 (6)
H9	0.427 (2)	0.659 (12)	0.5071 (15)	0.033 (11)*
Br10	0.41826 (2)	0.04521 (11)	0.315985 (15)	0.03005 (19)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0158 (15)	0.0262 (18)	0.0240 (16)	0.0011 (13)	−0.0009 (12)	0.0025 (14)
C2	0.0188 (15)	0.0263 (18)	0.0232 (16)	0.0026 (13)	−0.0001 (12)	0.0022 (14)
C3	0.0231 (18)	0.031 (2)	0.0248 (17)	0.0008 (14)	−0.0028 (14)	−0.0001 (14)
C4	0.0181 (16)	0.036 (2)	0.0326 (18)	−0.0030 (15)	−0.0053 (13)	0.0049 (16)
C5	0.0154 (15)	0.036 (2)	0.0308 (17)	0.0016 (14)	0.0007 (13)	0.0050 (16)
C6	0.0192 (17)	0.037 (2)	0.0225 (16)	0.0034 (15)	0.0012 (13)	0.0033 (15)
C7	0.0209 (17)	0.0309 (19)	0.0207 (16)	−0.0011 (14)	0.0009 (13)	0.0034 (14)
O8	0.0147 (12)	0.0520 (18)	0.0326 (13)	0.0064 (11)	−0.0052 (9)	−0.0121 (12)
O9	0.0183 (12)	0.0472 (17)	0.0277 (13)	0.0030 (12)	−0.0035 (10)	−0.0109 (12)
Br10	0.0190 (2)	0.0420 (3)	0.0286 (3)	0.00389 (14)	0.00077 (16)	−0.00733 (15)

Geometric parameters (Å, º)

C1—C2	1.400 (5)	C4—H4	0.9300
C1—C6	1.401 (5)	C5—C6	1.388 (5)
C1—C7	1.492 (5)	C5—H5	0.9300
C2—C3	1.392 (5)	C6—H6	0.9300
C2—Br10	1.901 (3)	C7—O8	1.217 (4)
C3—C4	1.389 (5)	C7—O9	1.319 (5)
C3—H3	0.9300	O9—H9	0.803 (19)
C4—C5	1.375 (5)
C2—C1—C6	117.5 (3)	C3—C4—H4	119.8
C2—C1—C7	124.4 (3)	C4—C5—C6	119.8 (3)
C6—C1—C7	118.1 (3)	C4—C5—H5	120.1
C3—C2—C1	121.1 (3)	C6—C5—H5	120.1
C3—C2—Br10	115.6 (3)	C5—C6—C1	121.5 (3)
C1—C2—Br10	123.3 (2)	C5—C6—H6	119.2
C4—C3—C2	119.7 (3)	C1—C6—H6	119.2
C4—C3—H3	120.2	O8—C7—O9	122.8 (3)
C2—C3—H3	120.2	O8—C7—C1	124.3 (3)
C5—C4—C3	120.4 (3)	O9—C7—C1	112.9 (3)
C5—C4—H4	119.8	C7—O9—H9	113 (3)
C6—C1—C2—C3	−1.6 (5)	C4—C5—C6—C1	0.1 (6)
C7—C1—C2—C3	175.8 (3)	C2—C1—C6—C5	1.3 (5)
C6—C1—C2—Br10	177.6 (3)	C7—C1—C6—C5	−176.3 (3)
C7—C1—C2—Br10	−4.9 (5)	C2—C1—C7—O8	−17.1 (6)
C1—C2—C3—C4	0.5 (6)	C6—C1—C7—O8	160.4 (4)
Br10—C2—C3—C4	−178.8 (3)	C2—C1—C7—O9	164.8 (3)
C2—C3—C4—C5	1.0 (6)	C6—C1—C7—O9	−17.7 (5)
C3—C4—C5—C6	−1.3 (6)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O9—H9···O8^i	0.81 (3)	1.84 (3)	2.643 (3)	177 (5)
C5—H5···O8^ii	0.93	2.65	3.514 (3)	153
C6—H6···O9^iii	0.93	2.64	3.417 (3)	141

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x−1/2, y+1/2, z; (iii) −x+1/2, −y+3/2, −z+1.