3,6-Dichloro­catechol

Abstract

The title compound, C₆H₄Cl₂O₂, exhibits a two-dimensional supra­molecular hydrogen-bonded network and forms a three-dimensional network supra­molecular structure via hydrogen bonds and π–π stacking of benzene rings. The π–π inter­actions are between the benzene rings of centrosymmetrically related mol­ecules, with centroid–centroid distances of 3.7676 (13) and 3.7107 (13) Å.

Related literature

For related literature, see: Haigler et al. (1988 ▶); Kirsh & Stan (1994 ▶); Nishizawa & Satoh (1975a ▶,b ▶); Sander et al. (1991 ▶); Schraa et al. (1986 ▶); Spiess et al. (1995 ▶); Spain et al. (1989 ▶).

Experimental

Crystal data

• C₆H₄Cl₂O₂

• M _r = 178.99

• Monoclinic,

• a = 7.4411 (7) Å

• b = 10.1283 (10) Å

• c = 10.6448 (8) Å

• β = 119.903 (5)°

• V = 695.45 (11) ų

• Z = 4

• Mo Kα radiation

• μ = 0.86 mm⁻¹

• T = 296 K

• 0.36 × 0.17 × 0.15 mm

Data collection

• Bruker SMART CCD area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 1997 ▶) T _min = 0.748, T _max = 0.882

• 3531 measured reflections

• 1243 independent reflections

• 1117 reflections with I > 2σ(I)

• R _int = 0.017

Refinement

• R[F ² > 2σ(F ²)] = 0.030

• wR(F ²) = 0.118

• S = 1.01

• 1243 reflections

• 93 parameters

• H-atom parameters constrained

• Δρ_max = 0.18 e Å⁻³

• Δρ_min = −0.34 e Å⁻³

Data collection: SMART (Bruker, 1997 ▶); cell refinement: SMART; data reduction: SAINT (Bruker, 1997 ▶); 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: SHELXTL.

Supplementary Material

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
O1—H1⋯O2	0.82	2.19	2.6391 (17)	115
O1—H1⋯Cl1i	0.82	2.76	3.3980 (16)	137
O2—H2⋯Cl2	0.82	2.61	3.0597 (13)	116
O2—H2⋯O1ii	0.82	2.13	2.8969 (19)	155

Symmetry codes: (i) ; (ii) .

supplementary crystallographic information

Comment

The compound 3,6-dichlorocatechol, (I), was a common metabolite in the microbial aerobic degradation of 1,4-dichlorobenzene. Because 1,4-dichlorobenzene was too stable to be degraded by photochemistry, biodegradation of this compound was an only way that it was eliminated from enviroment. 3,6-Dichlorocatechol has been reported to be an important intermediate in this process (Haigler et al., 1988; Schraa et al., 1986; Spain et al., 1989; Sander et al., 1991; Spiess et al., 1995). So the title compound (I) could be used to optimize the biodegradation process of 1,4-dichlorobenzene (Kirsh et al., 1994). It would be of great important significance in the protection of our surrounding and public health. Herein, we report the synthesis and structure of this compound, namely 3,6-dichlorocatechol. As shown in Fig.1, there are two hydroxyl groups in the phenyl ring. In the formation of these hydrogen bonds, one acts as donor, the other as acceptor. A two-dimensional supramolecular network was formed by O—H···Cl and O—H···O intermolecular hydrogen bonds (Table 1) [Symmetry codes (i): -x+2, y-1/2, -z+3/2; (ii): x, -y+3/2, z-1/2], and there are also weak π-π interactions between the centrosymmetrically related phenyl rings at (x, y, z) and (-x, -y, -z+1), (-x+1, -y, -z+1) with a centroid-to-centroid distance of 3.7676 (13)Å and 3.7107 (13)Å, respectively (Fig. 2).

Experimental

3,6,6-Tricholor-2-hydroxycyclohex-2-en-1-one (26 g, 0.12 mol) was treated with Li₂CO₃ (13.4 g, 0.18 mol) in DMF to give the title compound (I). (18.4 g) in 86% yield (Nishizawa & Satoh, 1975a,b). m. p. 108-109°C; ¹H NMR (CDCl₃, 300 MHz) δ: 5.79 (s, 2H), 6.86 (d, J = 2.4 Hz, 2H); ¹³ C NMR (CDCl₃, 75 MHz) δ: 118.7, 120.8, 140.6; MS (ESI) m/z (%): 178 (M+, 95), 180 (49), 182 (8).

Refinement

All H atoms were placed in geometrically idealized positions, with C—H = 0.93 Å and O—H = 0.82 Å, and constrained to ride on their respective parent atoms, with U_iso(H) = 1.2U_eq(C) and U_iso(H) = 1.5U_eq(O).

Figures

Fig. 1.

A view of the title compound, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

Fig. 2.

The three-dimensional structure by molecular packing, showing the intermolecular hydrogen bonds as yellow dashed lines [Symmetry codes: (i) -x+2, y-1/2, -z+3/2; (ii) x, -y+3/2, z-1/2], and π-π interactions as black dashed lines.

Crystal data

C6H4Cl2O2	F000 = 360
Mr = 178.99	Dx = 1.710 Mg m−3
Monoclinic, P21/c	Mo Kα radiation λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2193 reflections
a = 7.4411 (7) Å	θ = 2.9–26.4º
b = 10.1283 (10) Å	µ = 0.86 mm−1
c = 10.6448 (8) Å	T = 296 K
β = 119.903 (5)º	Block, colorless
V = 695.45 (11) Å3	0.36 × 0.17 × 0.15 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer	1243 independent reflections
Radiation source: fine-focus sealed tube	1117 reflections with I > 2σ(I)
Monochromator: graphite	Rint = 0.017
T = 296 K	θmax = 25.2º
φ and ω scans	θmin = 3.0º
Absorption correction: multi-scan(SADABS; Bruker, 1997)	h = −8→8
Tmin = 0.748, Tmax = 0.882	k = −9→12
3531 measured reflections	l = −12→12

Refinement

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)] = 0.030	H-atom parameters constrained
wR(F2) = 0.118	w = 1/[σ2(Fo2) + (0.01P)2] where P = (Fo2 + 2Fc2)/3
S = 1.01	(Δ/σ)max = 0.001
1243 reflections	Δρmax = 0.18 e Å−3
93 parameters	Δρmin = −0.34 e Å−3
Primary atom site location: structure-invariant direct methods	Extinction correction: none

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 takeninto account individually in the estimation of e.s.d.'s in distances, anglesand torsion angles; correlations between e.s.d.'s in cell parameters are onlyused 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 andgoodness of fit S are based on F2, conventional R-factors R are basedon F, with F set to zero for negative F2. The threshold expression ofF2 > σ(F2) is used only for calculating R-factors(gt) etc. and isnot relevant to the choice of reflections for refinement. R-factors basedon 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
Cl1	0.84969 (7)	1.04043 (6)	0.81747 (4)	0.0483 (3)
Cl2	0.64593 (7)	0.99288 (7)	0.17713 (4)	0.0529 (3)
O1	0.8451 (2)	0.79625 (12)	0.66807 (12)	0.0487 (4)
H1	0.8578	0.7331	0.6249	0.073*
O2	0.7560 (2)	0.76889 (12)	0.39645 (12)	0.0490 (4)
H2	0.7570	0.7708	0.3198	0.074*
C1	0.7904 (3)	1.02895 (16)	0.63843 (18)	0.0344 (4)
C2	0.7954 (2)	0.90633 (16)	0.58289 (15)	0.0335 (4)
C3	0.7515 (2)	0.89485 (16)	0.44037 (17)	0.0330 (4)
C4	0.7012 (3)	1.00694 (18)	0.35485 (17)	0.0356 (4)
C5	0.6955 (3)	1.13066 (18)	0.41095 (17)	0.0433 (4)
H5	0.6619	1.2056	0.3530	0.052*
C6	0.7397 (3)	1.14090 (18)	0.55181 (19)	0.0415 (4)
H6	0.7359	1.2230	0.5896	0.050*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Cl1	0.0647 (4)	0.0507 (4)	0.0356 (4)	−0.00327 (18)	0.0296 (3)	−0.00797 (16)
Cl2	0.0633 (4)	0.0666 (5)	0.0307 (4)	0.0071 (2)	0.0248 (3)	0.00907 (18)
O1	0.0832 (10)	0.0343 (7)	0.0401 (7)	0.0122 (6)	0.0393 (7)	0.0089 (5)
O2	0.0835 (10)	0.0351 (7)	0.0414 (7)	−0.0021 (6)	0.0409 (7)	−0.0039 (5)
C1	0.0382 (9)	0.0370 (9)	0.0307 (8)	−0.0029 (6)	0.0192 (7)	−0.0042 (6)
C2	0.0394 (8)	0.0323 (9)	0.0317 (8)	0.0010 (7)	0.0199 (7)	0.0053 (6)
C3	0.0373 (8)	0.0334 (9)	0.0298 (7)	−0.0025 (6)	0.0177 (6)	−0.0020 (6)
C4	0.0360 (9)	0.0445 (10)	0.0276 (8)	−0.0007 (7)	0.0169 (7)	0.0042 (7)
C5	0.0488 (10)	0.0354 (9)	0.0450 (9)	0.0037 (7)	0.0230 (8)	0.0100 (7)
C6	0.0508 (10)	0.0309 (9)	0.0429 (8)	0.0009 (7)	0.0234 (7)	−0.0003 (7)

Geometric parameters (Å, °)

O1—H1	0.8200	C3—O2	1.365 (2)
O2—H2	0.8200	C3—C4	1.385 (2)
C1—C2	1.384 (2)	C4—C5	1.398 (2)
C1—C6	1.390 (2)	C4—Cl2	1.7299 (16)
C1—Cl1	1.7326 (17)	C5—C6	1.369 (3)
C2—O1	1.3666 (18)	C5—H5	0.9300
C2—C3	1.388 (2)	C6—H6	0.9300
O1—C2—C1	120.31 (13)	C3—C4—C5	120.65 (15)
O1—C2—C3	119.68 (14)	C3—C4—Cl2	119.36 (13)
O2—C3—C4	125.85 (14)	C4—C3—C2	119.27 (15)
O2—C3—C2	114.84 (14)	C4—C5—H5	120.2
C1—C2—C3	120.02 (14)	C5—C4—Cl2	119.98 (13)
C1—C6—H6	119.9	C5—C6—C1	120.16 (16)
C2—O1—H1	109.5	C5—C6—H6	119.9
C2—C1—C6	120.32 (15)	C6—C5—C4	119.59 (15)
C2—C1—Cl1	118.94 (12)	C6—C1—Cl1	120.75 (13)
C3—O2—H2	109.5	C6—C5—H5	120.2
Cl1—C1—C2—O1	0.4 (2)	C1—C2—C3—C4	−0.5 (2)
Cl1—C1—C2—C3	−179.06 (12)	C2—C1—C6—C5	−0.3 (3)
Cl1—C1—C6—C5	179.23 (13)	C2—C3—C4—C5	0.3 (2)
Cl2—C4—C5—C6	−179.92 (13)	C2—C3—C4—Cl2	−179.90 (12)
O1—C2—C3—O2	2.1 (2)	C3—C4—C5—C6	−0.1 (3)
O1—C2—C3—C4	179.98 (15)	C4—C5—C6—C1	0.2 (3)
O2—C3—C4—C5	177.97 (16)	C6—C1—C2—O1	−179.97 (15)
O2—C3—C4—Cl2	−2.3 (2)	C6—C1—C2—C3	0.5 (2)
C1—C2—C3—O2	−178.41 (15)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O2	0.82	2.19	2.6391 (17)	115
O1—H1···Cl1i	0.82	2.76	3.3980 (16)	137
O2—H2···Cl2	0.82	2.61	3.0597 (13)	116
O2—H2···O1ii	0.82	2.13	2.8969 (19)	155

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