5-Chloro-1H-indole-3-carb-oxy-lic acid.

In the title compound, C(9)H(6)ClNO(2), the carboxyl group is twisted from the indole ring system by 9.00 (8)°. In the crystal, inversion dimers linked by pairs of O-H⋯O hydrogen bonds generate R(2) (2)(8) loops and N-H⋯O hydrogen bonds link the dimers into (001) sheets. Aromatic π-π stacking inter-actions [centroid-centroid distance = 3.7185 (12) A °] are also observed.

Related literature

For background to indole derivatives as pharmaceuticals, see: Kunzer & Wendt (2011 ▶); Woodward & Bartel (2005 ▶).

Experimental

Crystal data

C9H6ClNO2

M = 195.60

Orthorhombic,

a = 7.2934 (15) Å

b = 13.065 (3) Å

c = 17.902 (4) Å

V = 1705.9 (6) Å3

Z = 8

Mo Kα radiation

μ = 0.41 mm−1

T = 293 K

0.30 × 0.20 × 0.15 mm

Data collection

Rigaku SCXmini CCD diffractometer

Absorption correction: multi-scan (CrystalClear; Rigaku, 2005 ▶) T min = 0.907, T max = 0.941

16050 measured reflections

1919 independent reflections

1590 reflections with I > 2σ(I)

R int = 0.050

Refinement

R[F 2 > 2σ(F 2)] = 0.037

wR(F 2) = 0.104

S = 1.04

1919 reflections

123 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.17 e Å−3

Δρmin = −0.23 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.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811053384/hb6559sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811053384/hb6559Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536811053384/hb6559Isup3.cml

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

C9H6ClNO2	F(000) = 800
Mr = 195.60	Dx = 1.523 Mg m−3
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 1919 reflections
a = 7.2934 (15) Å	θ = 3.1–27.4°
b = 13.065 (3) Å	µ = 0.41 mm−1
c = 17.902 (4) Å	T = 293 K
V = 1705.9 (6) Å3	Block, colourless
Z = 8	0.30 × 0.20 × 0.15 mm

Rigaku SCXmini CCD diffractometer	1919 independent reflections
Radiation source: fine-focus sealed tube	1590 reflections with I > 2σ(I)
graphite	Rint = 0.050
Detector resolution: 13.6612 pixels mm-1	θmax = 27.4°, θmin = 3.1°
CCD_Profile_fitting scans	h = −9→9
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	k = −16→16
Tmin = 0.907, Tmax = 0.941	l = −23→23
16050 measured reflections

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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.104	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	w = 1/[σ2(Fo2) + (0.052P)2 + 0.5573P] where P = (Fo2 + 2Fc2)/3
1919 reflections	(Δ/σ)max < 0.001
123 parameters	Δρmax = 0.17 e Å−3
0 restraints	Δρmin = −0.23 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
Cl1	0.07292 (7)	0.95139 (4)	0.09595 (2)	0.05145 (18)
O2	0.05698 (16)	0.98847 (9)	0.40623 (6)	0.0402 (3)
C3	0.0835 (2)	0.89840 (12)	0.42814 (9)	0.0343 (3)
N1	0.2225 (2)	0.65957 (11)	0.33911 (8)	0.0428 (4)
C4	0.1415 (2)	0.81729 (11)	0.29670 (8)	0.0301 (3)
C6	0.1018 (2)	0.89102 (11)	0.24148 (8)	0.0329 (3)
H6	0.0636	0.9566	0.2542	0.040*
O1	0.0656 (2)	0.87130 (10)	0.49869 (6)	0.0568 (4)
H1	0.0422	0.9220	0.5240	0.085*
C5	0.1970 (2)	0.71749 (12)	0.27449 (9)	0.0350 (4)
C2	0.1353 (2)	0.81582 (11)	0.37768 (9)	0.0322 (3)
C9	0.1218 (2)	0.86192 (13)	0.16732 (9)	0.0365 (4)
C7	0.2150 (2)	0.68926 (13)	0.19938 (10)	0.0429 (4)
H7	0.2508	0.6235	0.1860	0.052*
C1	0.1853 (2)	0.71802 (13)	0.39985 (9)	0.0403 (4)
H1A	0.1924	0.6958	0.4491	0.048*
C8	0.1775 (2)	0.76284 (14)	0.14570 (9)	0.0434 (4)
H8	0.1890	0.7468	0.0953	0.052*
H1B	0.265 (3)	0.5983 (18)	0.3404 (11)	0.058 (6)*

	U11	U22	U33	U12	U13	U23
Cl1	0.0648 (3)	0.0559 (3)	0.0337 (2)	−0.0029 (2)	−0.00505 (19)	0.00701 (18)
O2	0.0590 (8)	0.0296 (6)	0.0320 (6)	0.0048 (5)	0.0087 (5)	0.0028 (4)
C3	0.0418 (9)	0.0338 (8)	0.0274 (7)	0.0000 (6)	0.0024 (6)	0.0008 (6)
N1	0.0569 (9)	0.0271 (7)	0.0443 (8)	0.0067 (6)	0.0023 (7)	0.0004 (6)
C4	0.0302 (7)	0.0293 (7)	0.0307 (8)	−0.0027 (6)	0.0013 (6)	−0.0031 (6)
C6	0.0350 (8)	0.0308 (7)	0.0331 (8)	−0.0013 (6)	0.0009 (6)	−0.0020 (6)
O1	0.1032 (12)	0.0388 (7)	0.0285 (6)	0.0165 (7)	0.0126 (7)	0.0045 (5)
C5	0.0353 (8)	0.0309 (8)	0.0387 (8)	−0.0004 (6)	0.0011 (6)	−0.0030 (6)
C2	0.0370 (8)	0.0302 (8)	0.0295 (8)	0.0001 (6)	0.0013 (6)	0.0011 (6)
C9	0.0369 (8)	0.0419 (9)	0.0306 (8)	−0.0046 (7)	−0.0015 (6)	−0.0005 (7)
C7	0.0498 (10)	0.0358 (9)	0.0432 (9)	0.0022 (7)	0.0038 (8)	−0.0122 (7)
C1	0.0526 (10)	0.0346 (8)	0.0338 (8)	0.0037 (7)	0.0013 (7)	0.0027 (6)
C8	0.0493 (10)	0.0496 (10)	0.0314 (8)	−0.0036 (8)	0.0023 (7)	−0.0119 (7)

Cl1—C9	1.7681 (17)	C6—C9	1.389 (2)
O2—C3	1.256 (2)	C6—H6	0.9300
C3—O1	1.3181 (19)	O1—H1	0.8200
C3—C2	1.457 (2)	C5—C7	1.400 (2)
N1—C1	1.356 (2)	C2—C1	1.387 (2)
N1—C5	1.395 (2)	C9—C8	1.411 (2)
N1—H1B	0.86 (2)	C7—C8	1.387 (3)
C4—C6	1.410 (2)	C7—H7	0.9300
C4—C5	1.422 (2)	C1—H1A	0.9300
C4—C2	1.451 (2)	C8—H8	0.9300
O2—C3—O1	122.39 (14)	C1—C2—C4	106.86 (13)
O2—C3—C2	122.71 (14)	C1—C2—C3	124.96 (14)
O1—C3—C2	114.89 (14)	C4—C2—C3	128.16 (14)
C1—N1—C5	109.45 (14)	C6—C9—C8	122.94 (15)
C1—N1—H1B	125.1 (14)	C6—C9—Cl1	119.25 (13)
C5—N1—H1B	125.2 (14)	C8—C9—Cl1	117.81 (12)
C6—C4—C5	119.26 (14)	C8—C7—C5	117.67 (15)
C6—C4—C2	134.69 (14)	C8—C7—H7	121.2
C5—C4—C2	106.02 (13)	C5—C7—H7	121.2
C9—C6—C4	117.48 (14)	N1—C1—C2	109.99 (15)
C9—C6—H6	121.3	N1—C1—H1A	125.0
C4—C6—H6	121.3	C2—C1—H1A	125.0
C3—O1—H1	109.5	C7—C8—C9	120.19 (15)
N1—C5—C7	129.87 (15)	C7—C8—H8	119.9
N1—C5—C4	107.67 (14)	C9—C8—H8	119.9
C7—C5—C4	122.45 (15)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O2i	0.82	1.86	2.6558 (17)	164
N1—H1B···O2ii	0.86 (2)	2.26 (2)	3.005 (2)	144.3 (19)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯O2i	0.82	1.86	2.6558 (17)	164
N1—H1B⋯O2ii	0.86 (2)	2.26 (2)	3.005 (2)	144.3 (19)

Symmetry codes: (i) ; (ii) .