6-Bromo-1H-indole-3-carb­oxy­lic acid

Abstract

In the title mol­ecule, C₉H₆BrNO₂, the dihedral angle between the –COOH group and the ring system is 6 (4)°. In the crystal, pairs of O—H⋯O hydrogen bonds link the mol­ecules into inversion dimers and these dimers are connected via N—H⋯O hydrogen bonds to form layers parallel to the (-101) plane.

Related literature  

For related literature, see: Lang et al. (2011 ▶); Luo et al. (2011 ▶).

Experimental  

Crystal data  

• C₉H₆BrNO₂

• M _r = 240.06

• Monoclinic,

• a = 7.2229 (14) Å

• b = 11.874 (2) Å

• c = 11.079 (2) Å

• β = 108.37 (3)°

• V = 901.7 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 4.52 mm⁻¹

• T = 293 K

• 0.30 × 0.23 × 0.20 mm

Data collection  

• Rigaku SCXmini diffractometer

• Absorption correction: multi-scan (CrystalClear; Rigaku, 2005 ▶) T _min = 0.977, T _max = 0.984

• 8876 measured reflections

• 2051 independent reflections

• 1284 reflections with I > 2σ(I)

• R _int = 0.082

Refinement  

• R[F ² > 2σ(F ²)] = 0.063

• wR(F ²) = 0.158

• S = 1.06

• 2051 reflections

• 122 parameters

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

• Δρ_max = 0.52 e Å⁻³

• Δρ_min = −0.76 e Å⁻³

Data collection: CrystalClear (Rigaku, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Supplementary material file. DOI: 10.1107/S1600536812006381/aa2041Isup3.cml

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H7⋯O1i	0.97 (9)	1.67 (10)	2.627 (5)	169 (8)
N1—H1A⋯O1ii	0.86	2.16	2.928 (6)	148

Symmetry codes: (i) ; (ii) .

supplementary crystallographic information

Comment

Indole derivatives such as indole-3-carboxylates are important building blocks in the synthesis of many pharmaceuticals and biologically active compounds. (Lang et al., 2011; Luo,et al., 2011). In the crystal structure of the title compound (Fig. 1), intermolecular O—H···O hydrogen bonds link the molecules into dimers and the dimers are connected via intermolecular N—H···O hydrogen bonds forming layers parallel to (101) plane (Table 1, Fig. 2).

Experimental

A solution of the title compound (0.2 g) in methanol (20 ml) was placed in a dark place. Yellow single crystals suitable for X-ray diffraction study were obtained by slow evaporation of the solution over a period of 7 d.

Refinement

H atoms attached to C and N were placed into calculated positions and treated as riding with C—H = 0.93 Å, N—H = 0.86 Å and U_iso(H) = 1.2U_eq(C, N). Carboxylic H atom was found from difference maps and refined independently.

Figures

Fig. 1.

The molecular structure of the title compound with the atom labelling scheme. Displacement ellipsoids are drawn at 30% probability level.

Fig. 2.

A packing diagram of the title compound. Intermolecular hydrogen bonds are shown as dashed lines.

Crystal data

C9H6BrNO2	F(000) = 472
Mr = 240.06	Dx = 1.768 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 2051 reflections
a = 7.2229 (14) Å	θ = 3.0–27.5°
b = 11.874 (2) Å	µ = 4.52 mm−1
c = 11.079 (2) Å	T = 293 K
β = 108.37 (3)°	Prism, brown
V = 901.7 (3) Å3	0.30 × 0.23 × 0.20 mm
Z = 4

Data collection

Rigaku SCXmini diffractometer	2051 independent reflections
Radiation source: fine-focus sealed tube	1284 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.082
Detector resolution: 13.6612 pixels mm-1	θmax = 27.5°, θmin = 3.0°
CCD_Profile_fitting scans	h = −9→9
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	k = −15→14
Tmin = 0.977, Tmax = 0.984	l = −14→14
8876 measured reflections

Refinement

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)] = 0.063	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.158	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ2(Fo2) + (0.0513P)2 + 1.7606P] where P = (Fo2 + 2Fc2)/3
2051 reflections	(Δ/σ)max < 0.001
122 parameters	Δρmax = 0.52 e Å−3
0 restraints	Δρmin = −0.76 e Å−3

Special details

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.

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

	x	y	z	Uiso*/Ueq
Br1	0.08018 (10)	0.38905 (7)	0.15536 (6)	0.0777 (4)
C5	0.2174 (7)	0.5896 (4)	0.4756 (5)	0.0394 (12)
O2	0.4390 (7)	0.4389 (3)	0.8444 (4)	0.0571 (12)
O1	0.4564 (6)	0.6167 (3)	0.9140 (3)	0.0453 (9)
C3	0.4157 (7)	0.5477 (4)	0.8231 (5)	0.0369 (12)
N1	0.2185 (7)	0.6961 (4)	0.5252 (4)	0.0457 (11)
H1A	0.1800	0.7563	0.4813	0.055*
C4	0.2939 (7)	0.5144 (4)	0.5765 (5)	0.0366 (11)
C9	0.3036 (8)	0.4004 (5)	0.5495 (5)	0.0452 (13)
H9A	0.3525	0.3484	0.6146	0.054*
C8	0.2397 (9)	0.3663 (5)	0.4251 (6)	0.0504 (14)
H8A	0.2447	0.2902	0.4063	0.060*
C2	0.3405 (7)	0.5824 (4)	0.6922 (5)	0.0361 (11)
C1	0.2896 (7)	0.6912 (4)	0.6539 (5)	0.0421 (13)
H1B	0.3021	0.7525	0.7082	0.051*
C7	0.1676 (7)	0.4426 (5)	0.3265 (5)	0.0440 (13)
C6	0.1550 (7)	0.5551 (5)	0.3481 (5)	0.0459 (14)
H6A	0.1075	0.6061	0.2818	0.055*
H7	0.484 (13)	0.427 (7)	0.936 (9)	0.13 (3)*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Br1	0.0665 (5)	0.1168 (7)	0.0510 (4)	−0.0166 (4)	0.0201 (3)	−0.0338 (4)
C5	0.037 (3)	0.040 (3)	0.041 (3)	0.000 (2)	0.012 (2)	−0.002 (2)
O2	0.095 (3)	0.029 (2)	0.041 (2)	−0.002 (2)	0.012 (2)	0.0027 (17)
O1	0.065 (2)	0.0304 (19)	0.038 (2)	−0.0045 (18)	0.0119 (18)	−0.0017 (15)
C3	0.039 (3)	0.032 (3)	0.039 (3)	0.000 (2)	0.011 (2)	−0.001 (2)
N1	0.057 (3)	0.035 (2)	0.043 (3)	0.009 (2)	0.014 (2)	0.011 (2)
C4	0.038 (3)	0.035 (3)	0.037 (3)	−0.001 (2)	0.013 (2)	−0.001 (2)
C9	0.055 (3)	0.041 (3)	0.042 (3)	0.003 (3)	0.018 (3)	0.003 (2)
C8	0.058 (4)	0.044 (3)	0.055 (4)	−0.008 (3)	0.026 (3)	−0.015 (3)
C2	0.039 (3)	0.032 (3)	0.037 (3)	−0.004 (2)	0.012 (2)	−0.001 (2)
C1	0.047 (3)	0.032 (3)	0.044 (3)	0.001 (2)	0.011 (3)	−0.002 (2)
C7	0.039 (3)	0.060 (4)	0.036 (3)	−0.009 (3)	0.016 (2)	−0.010 (3)
C6	0.040 (3)	0.064 (4)	0.031 (3)	0.003 (3)	0.008 (2)	0.006 (3)

Geometric parameters (Å, º)

Br1—C7	1.908 (5)	C4—C9	1.394 (7)
C5—N1	1.377 (7)	C4—C2	1.461 (7)
C5—C6	1.402 (7)	C9—C8	1.369 (8)
C5—C4	1.401 (7)	C9—H9A	0.9300
O2—C3	1.315 (6)	C8—C7	1.388 (8)
O2—H7	0.97 (9)	C8—H8A	0.9300
O1—C3	1.259 (6)	C2—C1	1.374 (7)
C3—C2	1.439 (7)	C1—H1B	0.9300
N1—C1	1.356 (6)	C7—C6	1.365 (8)
N1—H1A	0.8600	C6—H6A	0.9300
N1—C5—C6	129.0 (5)	C9—C8—C7	121.5 (5)
N1—C5—C4	108.4 (4)	C9—C8—H8A	119.2
C6—C5—C4	122.6 (5)	C7—C8—H8A	119.2
C3—O2—H7	108 (5)	C1—C2—C3	124.0 (5)
O1—C3—O2	120.8 (5)	C1—C2—C4	106.5 (4)
O1—C3—C2	122.6 (4)	C3—C2—C4	129.4 (5)
O2—C3—C2	116.6 (5)	N1—C1—C2	109.9 (5)
C1—N1—C5	109.5 (4)	N1—C1—H1B	125.0
C1—N1—H1A	125.3	C2—C1—H1B	125.0
C5—N1—H1A	125.3	C6—C7—C8	122.0 (5)
C9—C4—C5	118.8 (5)	C6—C7—Br1	118.7 (4)
C9—C4—C2	135.4 (5)	C8—C7—Br1	119.3 (4)
C5—C4—C2	105.8 (4)	C7—C6—C5	116.4 (5)
C8—C9—C4	118.7 (5)	C7—C6—H6A	121.8
C8—C9—H9A	120.7	C5—C6—H6A	121.8
C4—C9—H9A	120.7

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H7···O1i	0.97 (9)	1.67 (10)	2.627 (5)	169 (8)
N1—H1A···O1ii	0.86	2.16	2.928 (6)	148

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