2-(2,4-Dichloro-phen-yl)acetic acid.

In the title compound, C(8)H(6)Cl(2)O(2), the dihedral angle between the C-C(=O)-OH carboxyl unit and the benzene ring is 70.70 (4)°. In the crystal, mol-ecules are linked into inversion dimers by pairs of O-H⋯O hydrogen bonds. The dimers are linked into chains extending along [001] by weak C-H⋯Cl inter-actions.

Related literature

For background to carboxylic acids as supra­molecular synthons, see: Thalladi et al. (1996 ▶). For related structures, see: Hodgson & Asplund (1991 ▶); Li et al. (2010 ▶).

Experimental

Crystal data

C8H6Cl2O2

M = 205.03

Monoclinic,

a = 10.824 (2) Å

b = 5.6061 (11) Å

c = 13.820 (3) Å

β = 91.08 (3)°

V = 838.4 (3) Å3

Z = 4

Mo Kα radiation

μ = 0.72 mm−1

T = 113 K

0.24 × 0.20 × 0.12 mm

Data collection

Rigaku Saturn CCD diffractometer

Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005 ▶) T min = 0.846, T max = 0.918

5321 measured reflections

1484 independent reflections

1237 reflections with I > 2σ(I)

R int = 0.037

Refinement

R[F 2 > 2σ(F 2)] = 0.027

wR(F 2) = 0.075

S = 1.10

1484 reflections

111 parameters

H-atom parameters constrained

Δρmax = 0.23 e Å−3

Δρmin = −0.22 e Å−3

Data collection: CrystalClear (Rigaku/MSC, 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: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809052453/hb5271sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809052453/hb5271Isup2.hkl

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

C8H6Cl2O2	F(000) = 416
Mr = 205.03	Dx = 1.624 Mg m−3
Monoclinic, P21/n	Melting point = 403–405 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 10.824 (2) Å	Cell parameters from 2684 reflections
b = 5.6061 (11) Å	θ = 2.4–27.9°
c = 13.820 (3) Å	µ = 0.72 mm−1
β = 91.08 (3)°	T = 113 K
V = 838.4 (3) Å3	Block, colourless
Z = 4	0.24 × 0.20 × 0.12 mm

Rigaku Saturn CCD diffractometer	1484 independent reflections
Radiation source: rotating anode	1237 reflections with I > 2σ(I)
confocal	Rint = 0.037
Detector resolution: 7.31 pixels mm-1	θmax = 25.0°, θmin = 2.4°
ω and φ scans	h = −12→12
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005)	k = −6→6
Tmin = 0.846, Tmax = 0.918	l = −10→16
5321 measured reflections

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)] = 0.027	H-atom parameters constrained
wR(F2) = 0.075	w = 1/[σ2(Fo2) + (0.0435P)2] where P = (Fo2 + 2Fc2)/3
S = 1.10	(Δ/σ)max = 0.001
1484 reflections	Δρmax = 0.23 e Å−3
111 parameters	Δρmin = −0.22 e Å−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.073 (5)

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	0.71462 (4)	0.15511 (7)	0.45827 (3)	0.02309 (18)
Cl2	0.35390 (4)	0.34376 (7)	0.70900 (3)	0.02349 (18)
O1	0.55180 (10)	0.4443 (2)	0.88848 (8)	0.0230 (3)
O2	0.46215 (12)	0.7778 (2)	0.94126 (8)	0.0266 (3)
H2	0.4593	0.7022	0.9920	0.040*
C1	0.67428 (16)	0.6663 (3)	0.65565 (12)	0.0196 (4)
H1	0.7191	0.7977	0.6777	0.024*
C2	0.72229 (14)	0.5277 (3)	0.58229 (11)	0.0203 (4)
H2A	0.7977	0.5660	0.5551	0.024*
C3	0.65595 (15)	0.3314 (3)	0.55033 (11)	0.0166 (4)
C4	0.54302 (14)	0.2735 (3)	0.58966 (11)	0.0176 (4)
H4	0.4990	0.1408	0.5680	0.021*
C5	0.49744 (14)	0.4168 (3)	0.66162 (11)	0.0165 (4)
C6	0.56134 (14)	0.6155 (3)	0.69727 (11)	0.0155 (4)
C7	0.51115 (15)	0.7662 (3)	0.77720 (11)	0.0188 (4)
H7A	0.5601	0.9107	0.7826	0.023*
H7B	0.4272	0.8125	0.7601	0.023*
C8	0.51103 (15)	0.6439 (3)	0.87375 (12)	0.0173 (4)

	U11	U22	U33	U12	U13	U23
Cl1	0.0220 (3)	0.0288 (3)	0.0187 (3)	0.00182 (16)	0.00584 (19)	−0.00592 (16)
Cl2	0.0160 (2)	0.0273 (3)	0.0274 (3)	−0.00391 (15)	0.00862 (19)	−0.00387 (17)
O1	0.0288 (6)	0.0256 (7)	0.0146 (6)	0.0115 (5)	0.0033 (5)	−0.0024 (5)
O2	0.0387 (8)	0.0245 (7)	0.0168 (6)	0.0114 (6)	0.0075 (6)	−0.0012 (5)
C1	0.0210 (9)	0.0183 (9)	0.0195 (9)	−0.0041 (6)	0.0008 (8)	0.0001 (7)
C2	0.0158 (8)	0.0250 (9)	0.0203 (9)	−0.0023 (7)	0.0046 (7)	0.0027 (7)
C3	0.0194 (8)	0.0192 (9)	0.0114 (8)	0.0035 (7)	0.0018 (7)	0.0015 (6)
C4	0.0179 (8)	0.0182 (8)	0.0168 (8)	−0.0013 (7)	−0.0004 (7)	−0.0024 (7)
C5	0.0130 (8)	0.0213 (8)	0.0153 (8)	−0.0004 (6)	0.0017 (6)	0.0047 (7)
C6	0.0193 (8)	0.0161 (8)	0.0111 (8)	0.0013 (6)	−0.0003 (7)	0.0028 (6)
C7	0.0210 (8)	0.0163 (8)	0.0191 (9)	0.0007 (7)	0.0004 (7)	−0.0005 (7)
C8	0.0135 (8)	0.0232 (10)	0.0151 (8)	0.0003 (6)	0.0017 (7)	−0.0044 (6)

Cl1—C3	1.7405 (16)	C2—H2A	0.9300
Cl2—C5	1.7460 (16)	C3—C4	1.386 (2)
O1—C8	1.2185 (19)	C4—C5	1.377 (2)
O2—C8	1.316 (2)	C4—H4	0.9300
O2—H2	0.8200	C5—C6	1.396 (2)
C1—C2	1.386 (2)	C6—C7	1.501 (2)
C1—C6	1.390 (2)	C7—C8	1.500 (2)
C1—H1	0.9300	C7—H7A	0.9700
C2—C3	1.382 (2)	C7—H7B	0.9700
C8—O2—H2	109.5	C4—C5—Cl2	117.86 (12)
C2—C1—C6	122.16 (15)	C6—C5—Cl2	119.55 (13)
C2—C1—H1	118.9	C1—C6—C5	116.81 (15)
C6—C1—H1	118.9	C1—C6—C7	121.50 (14)
C3—C2—C1	118.72 (15)	C5—C6—C7	121.68 (15)
C3—C2—H2A	120.6	C8—C7—C6	113.81 (13)
C1—C2—H2A	120.6	C8—C7—H7A	108.8
C2—C3—C4	121.21 (15)	C6—C7—H7A	108.8
C2—C3—Cl1	119.43 (13)	C8—C7—H7B	108.8
C4—C3—Cl1	119.36 (12)	C6—C7—H7B	108.8
C5—C4—C3	118.50 (15)	H7A—C7—H7B	107.7
C5—C4—H4	120.7	O1—C8—O2	123.67 (16)
C3—C4—H4	120.7	O1—C8—C7	124.19 (15)
C4—C5—C6	122.59 (15)	O2—C8—C7	112.14 (13)
C6—C1—C2—C3	−0.6 (2)	C4—C5—C6—C1	0.9 (2)
C1—C2—C3—C4	0.5 (2)	Cl2—C5—C6—C1	−179.10 (11)
C1—C2—C3—Cl1	179.98 (12)	C4—C5—C6—C7	−178.68 (14)
C2—C3—C4—C5	0.2 (2)	Cl2—C5—C6—C7	1.3 (2)
Cl1—C3—C4—C5	−179.22 (11)	C1—C6—C7—C8	−109.95 (17)
C3—C4—C5—C6	−1.0 (2)	C5—C6—C7—C8	69.59 (19)
C3—C4—C5—Cl2	179.02 (11)	C6—C7—C8—O1	2.7 (2)
C2—C1—C6—C5	−0.1 (2)	C6—C7—C8—O2	−177.59 (13)
C2—C1—C6—C7	179.49 (14)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O1i	0.82	1.85	2.6689 (16)	175
C4—H4···Cl1ii	0.93	2.86	3.731 (2)	156

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O1i	0.82	1.85	2.6689 (16)	175
C4—H4⋯Cl1ii	0.93	2.86	3.731 (2)	156

Symmetry codes: (i) ; (ii) .