5-Chloro-2-hydroxy­benzene-1,3-dicarb­aldehyde

In the crystal structure of the title compound, C₈H₅ClO₃, both formyl groups are in the plane of the chloro­phenyl unit and the mol­ecule is stabilized by intra­molecular O—H...O hydrogen bonding. The mol­ecules are connected via inter­molecular O—H...O hydrogen bonding into chains and are stacked into columns with a centroid–centroid distance between adjacent aromatic rings of 3.914 (2) Å.

Key indicators

• Single-crystal X-ray study
• T = 291 K
• Mean [sigma](C-C)= 0.003 Å
• R factor = 0.035
• wR factor = 0.092
• Data-to-parameter ratio = 10.8

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S1. Comment

Hydroxyisophthalaldehyde and its derivatives are an important class of intermediates used in synthesizing macrocyclic compounds. In recent years, a continuing attention has been drawn to them and their metal complexes (Huang et al., 2006). In this paper, we report the X-ray single-crystal structure of 2,6-diformyl-4-chlorophenol prepared from 4-chloro-2,6-bis(hydroxymethyl)phenol.

The molecule of the title compound is essentially planar and all structural parameters (Fig. 1) are in good agreement with those found in similar compounds (Chu et al., 2005; Chu & Huang, 2006). There is one weak intramolecular O-H···O hydrogen bond between the hydroxyl group at O1 and the carbonyl group O3.

In the crystal structure of the title compound the molecules are connected into chains by intermolecular O-H···O hydrogen bonding (Fig. 2 and Table 1). The molecules are stacked into columns in the direction of the crystallographic a-axis in order that π–π stacking interactions are maximized. The dihedral angle between two adjacent rings amount to 63.5 (2)° and the centroid-centroid separation is 3.914 (2) Å (Fig. 3).

Related literature

For related compounds, see: Huang et al. (2000, 2006); Chu et al. (2005); Chu & Huang (2006).

S2. Experimental

4-Chloro-2,6-diformylphenol was prepared by an improved oxidation method using activated manganese (IV) dioxide (Huang et al., 2000) from 4-chloro-2,6-bis(hydroxymethyl)phenol (Chu et al., 2005). Single crystals suitable for X-ray diffraction measurement were grown from a chloroform solution by slow evaporation of the solvent at room temperature.

S3. Refinement

The C-H H atoms were located in difference map and were refined with varying coordinates isotropic. The O-H H atom was placed with idealized geometry allowed to rotata but not to tip O—H = 0.82 Å) and was refined using a riding model with U_iso(H) = 1.5U_eq(O).

Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. An ORTEP drawing of the title compound with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level and intramolecular hydrogen bonds is shown as dashed lines.
	Fig. 2. A perspective view of the one-dimensional hydrogen-bonded chain of the title compound.
	Fig. 3. Crystal structure of the title compound with view along the a-axis (intermolecular O-H···O hydrogen bonding is shown as dashed lines).

5-Chloro-2-hydroxybenzene-1,3-dicarbaldehyde

Crystal data

C8H5ClO3	F(000) = 376
Mr = 184.57	Dx = 1.630 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1370 reflections
a = 7.5554 (15) Å	θ = 2.7–28.1°
b = 3.9144 (8) Å	µ = 0.46 mm^−1
c = 25.676 (5) Å	T = 291 K
β = 97.921 (3)°	Block, yellow
V = 752.1 (3) Å^3	0.20 × 0.18 × 0.16 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer	1353 independent reflections
Radiation source: fine-focus sealed tube	1070 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.076
ϕ and ω scans	θmax = 25.2°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Bruker, 2000)	h = −9→8
Tmin = 0.913, Tmax = 0.930	k = −4→4
3517 measured reflections	l = −30→28

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 = 0.97	w = 1/[σ^2(Fo^2) + (0.0457P)^2] where P = (Fo^2 + 2Fc^2)/3
1353 reflections	(Δ/σ)max = 0.001
125 parameters	Δρmax = 0.19 e Å^−3
0 restraints	Δρmin = −0.27 e Å^−3

Special details

Experimental. The structure was solved by direct methods (Bruker, 2000) and successive difference Fourier syntheses.

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
C1	0.4171 (2)	0.4316 (4)	0.33617 (6)	0.0342 (4)
C2	0.5238 (2)	0.6213 (5)	0.37437 (7)	0.0355 (4)
C3	0.4574 (2)	0.7115 (5)	0.42026 (8)	0.0384 (4)
C4	0.2876 (2)	0.6140 (5)	0.42836 (7)	0.0382 (4)
C5	0.1802 (2)	0.4303 (5)	0.39068 (7)	0.0372 (4)
C6	0.2425 (2)	0.3385 (5)	0.34400 (7)	0.0348 (4)
C7	0.7038 (3)	0.7330 (5)	0.36545 (9)	0.0447 (5)
C8	0.1285 (3)	0.1496 (5)	0.30341 (8)	0.0426 (5)
Cl1	0.20868 (7)	0.73166 (14)	0.486064 (19)	0.0550 (2)
H3	0.532 (3)	0.831 (5)	0.4454 (7)	0.047 (5)*
H5	0.064 (3)	0.358 (5)	0.3977 (8)	0.052 (5)*
H7	0.747 (3)	0.653 (5)	0.3360 (8)	0.052 (6)*
H8	0.015 (2)	0.099 (5)	0.3119 (7)	0.044 (5)*
O1	0.48613 (16)	0.3399 (3)	0.29244 (5)	0.0467 (4)
H1	0.4106	0.2351	0.2726	0.070*
O2	0.79414 (18)	0.9339 (4)	0.39307 (6)	0.0606 (4)
O3	0.17345 (17)	0.0628 (4)	0.26168 (5)	0.0544 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0313 (9)	0.0364 (10)	0.0359 (9)	0.0027 (8)	0.0079 (7)	0.0064 (8)
C2	0.0293 (9)	0.0375 (10)	0.0404 (10)	0.0016 (8)	0.0068 (7)	0.0059 (8)
C3	0.0349 (10)	0.0375 (11)	0.0424 (11)	−0.0001 (8)	0.0034 (8)	0.0017 (8)
C4	0.0372 (10)	0.0403 (10)	0.0388 (10)	0.0048 (8)	0.0110 (8)	0.0052 (8)
C5	0.0266 (9)	0.0412 (11)	0.0447 (10)	0.0026 (8)	0.0078 (8)	0.0096 (8)
C6	0.0295 (10)	0.0352 (10)	0.0392 (10)	0.0020 (7)	0.0026 (7)	0.0074 (8)
C7	0.0320 (11)	0.0524 (13)	0.0504 (12)	−0.0027 (9)	0.0083 (9)	−0.0016 (10)
C8	0.0329 (11)	0.0487 (12)	0.0456 (11)	−0.0010 (9)	0.0036 (8)	0.0062 (9)
Cl1	0.0548 (4)	0.0668 (4)	0.0475 (3)	−0.0021 (2)	0.0221 (2)	−0.0052 (2)
O1	0.0400 (7)	0.0626 (9)	0.0393 (7)	−0.0074 (6)	0.0120 (5)	−0.0060 (6)
O2	0.0404 (8)	0.0732 (10)	0.0689 (9)	−0.0158 (8)	0.0099 (7)	−0.0082 (8)
O3	0.0454 (8)	0.0680 (10)	0.0488 (8)	−0.0076 (7)	0.0036 (6)	−0.0092 (7)

Geometric parameters (Å, º)

C1—O1	1.3500 (19)	C5—C6	1.394 (2)
C1—C2	1.395 (2)	C5—H5	0.96 (2)
C1—C6	1.409 (2)	C6—C8	1.459 (3)
C2—C3	1.388 (2)	C7—O2	1.206 (2)
C2—C7	1.476 (2)	C7—H7	0.92 (2)
C3—C4	1.382 (2)	C8—O3	1.216 (2)
C3—H3	0.926 (19)	C8—H8	0.938 (18)
C4—C5	1.377 (3)	O1—H1	0.8200
C4—Cl1	1.7337 (17)
O1—C1—C2	118.32 (15)	C4—C5—H5	119.1 (12)
O1—C1—C6	121.75 (15)	C6—C5—H5	120.6 (12)
C2—C1—C6	119.93 (15)	C5—C6—C1	119.33 (16)
C3—C2—C1	119.40 (16)	C5—C6—C8	120.57 (16)
C3—C2—C7	120.30 (17)	C1—C6—C8	120.10 (16)
C1—C2—C7	120.27 (16)	O2—C7—C2	124.11 (19)
C4—C3—C2	120.61 (18)	O2—C7—H7	118.0 (13)
C4—C3—H3	121.7 (12)	C2—C7—H7	117.8 (13)
C2—C3—H3	117.7 (12)	O3—C8—C6	124.18 (18)
C5—C4—C3	120.54 (16)	O3—C8—H8	121.5 (11)
C5—C4—Cl1	120.03 (13)	C6—C8—H8	114.3 (11)
C3—C4—Cl1	119.42 (15)	C1—O1—H1	109.5
C4—C5—C6	120.17 (16)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O1^i	0.82	2.48	2.9581 (19)	118
O1—H1···O3	0.82	1.90	2.6204 (18)	146

Symmetry code: (i) −x+1, y−1/2, −z+1/2.