2,4-Di­chloro-6-({2-[(3,5-di­chloro-2-hy­dr­oxy­benzyl­­idene)amino]­eth­yl}imino­meth­yl)phenol

The title mol­ecule, C₁₆H₁₂Cl₄N₂O₂, lies about an inversion center. The symmetry-unique part of the mol­ecule contains an intra­molecular O—H⋯N hydrogen bond. In the crystal, mol­ecules are arranged in corrugated layers parallel to (-101). Weak π–π stacking inter­actions, with a centroid–centroid diatance of 3.7923 (13) Å, are present.

Related literature

For the preparation of the title compound, see: Lu & Xia (2006); Trivedi et al. (1992). For the synthesis of similar compounds, see: Kadish et al. (1990); Taylor et al. (1991); Moutet & Ourari (1997) Ourari et al. (2008b, 2011). For their applications, see: Ourari et al. (2008a); Kadish et al. (1990).

Experimental

Crystal data

• C₁₆H₁₂Cl₄N₂O₂

• M_r = 406.08

• Monoclinic, P 2₁ /c

• a = 7.529 (1) Å

• b = 10.718 (2) Å

• c = 10.759 (2) Å

• β = 101.40 (2)°

• V = 851.1 (3) ų

• Z = 2

• Mo Kα radiation

• μ = 0.71 mm⁻¹

• T = 295 K

• 0.50 × 0.23 × 0.19 mm

Data collection

• Stoe IPDS diffractometer

• Absorption correction: gaussian (ABSGAUSS in PLATON; Spek, 2009) T_min = 0.794, T_max = 0.893

• 8137 measured reflections

• 1671 independent reflections

• 1192 reflections with I > 2σ(I)

• R_int = 0.049

Refinement

• R[F² > 2σ(F²)] = 0.031

• wR(F²) = 0.081

• S = 0.94

• 1671 reflections

• 110 parameters

• H-atom parameters constrained

• Δρ_max = 0.19 e Å⁻³

• Δρ_min = −0.15 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O9—H9⋯N2	0.82	1.84	2.562 (2)	147

Data collection: EXPOSE (Stoe & Cie, 1999); cell refinement: SELECT and CELL (Stoe & Cie, 1999); data reduction: INTEGRATE (Stoe & Cie, 1999); program(s) used to solve structure: SIR2002 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg & Berndt, 2001); software used to prepare material for publication: WinGX (Farrugia, 1999).

Supporting information

S1. Comment

The synthesis of new chelating agents such as Schiff bases became an extensive area of research owing to their high structural versatility. This is due to their high ability to coordinate transition metals leading to the corresponding complexes. This class of compounds may be involved in many applications as in coordination chemistry, biology, analysis, catalysis and electrocatalysis (Ourari et al., 2008a; Kadish et al., 1990). Herein, we report the preparation and crystal structure the of the title compound. These type of polyhalogenated ligands are endowed with high resistance towards oxidation reactions seeing that the chlorine atoms are adequately grafted at ortho and para-positions of the phenolic entities, preventing their further oxidation reactions as it was early reported for the porphyrinic complexes (Kadish et al., 1990; Taylor et al., 1991; Moutet et al., 1997). Some mononuclear complexes of Schiff base-Mn(III) compounds have been synthesized and used as catalysts towards epoxidation of olefins. This showed that the dihalogenated complexes behaved as the most efficient catalysts. Recently, we have as confirmed this observation when studying their analogues such as as those of iron(III) (Ourari et al., 2008b) and ruthenium(III) (Ourari et al., 2011) for the same oxidation reactions.

The molecular structure of (I) is shown in Fig. 1. The asymmetric unit of the title compound, consists of one-half of the molecule, with the other half generated by a crystallographic inversion centre. The crystal packing can be described as corrugated layers paralel to (-101) (Fig. 2). Fig. 3 shows the crystal structure with helical chains of molecules as a result of the 2₁ screw axes. There are two intramolecular O—H···N hydrogen bonds in the molecule (Table 1, Fig. 2). Weak π–π stacking interactions with a centroid to centroid distance 3.7923 (13) Å are present between inversion related molecules.

Related literature

For the preparation of the title compound, see: Lu & Xia (2006); Trivedi et al. (1992). For the synthesis of similar compounds, see: Kadish et al. (1990); Taylor et al. (1991); Moutet & Ourari (1997) Ourari et al. (2008b, 2011). For their applications, see: Ourari et al. (2008a); Kadish et al. (1990).

S2. Experimental

All reagents were AR grade, obtained from Alfa Aesar Chemical Company. 3, 5-Dichlorosalicylaldehyde, 1,2-diaminoethane and anhydrous ethanol were used without any further purification. The ligand prepared in this work was performed according the literature (Lu et al., 2006; Trivedi et al., 1992). Thus, a solution of 3, 5-dichlorosalicylaldehyde 382 mg (2.10^-3 mole) in anhydrous ethanol (10 ml) was dropwise added to a stirring ethanolic solution (10 ml), containing 60 mg (1.10^-3 mole) of ethylenediamine. The reaction mixture was refluxed for about 2 h leading to the formation of a yellow precipitate. This precipitate was collected by filtration, washed several times with ethanol and then dried on phosphoric anhydride (P₂O₅), its yield is of 90%. The resulting compound (I) was re-crystallized from a solvent mixture dichloromethane/acetone with the volume proportions 90 and 10, respectively. Under the slow evaporation, suitable crystals for X-ray diffraction were obtained.

S3. Refinement

H atoms were located in difference Fourier maps but introduced in calculated positions and treated as riding on their parent atoms (C and O) with C—H = 0.93 Å (methine, aromatic), 0.97 Å (methylene) and O—H = 0.82 Å (hydroxyl) with U_iso(H) = 1.2U_eq(C) or U_iso(H) = 1.5U_eq(O).

Computing details

Data collection: EXPOSE (Stoe & Cie, 1999); cell refinement: SELECT and CELL (Stoe & Cie, 1999); data reduction: INTEGRATE (Stoe & Cie, 1999); program(s) used to solve structure: SIR2002 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg & Berndt, 2001); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. The molecular structure of the title compound with displacement ellipsoid drawn at the 50% probability level. H atoms are represented as small spheres of arbitrary radii. Symmetry code: (i)-x+1, -y, -z
	Fig. 2. Layers of molecules paralel to (-101). Dash lines indicate hydrogen bonds.
	Fig. 3. A projection of part of the crystal structure along [001].

2,4-Dichloro-6-({2-[(3,5-dichloro-2- hydroxybenzylidene)amino]ethyl}iminomethyl)phenol

Crystal data

C16H12Cl4N2O2	F(000) = 412
Mr = 406.08	Dx = 1.585 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4871 reflections
a = 7.529 (1) Å	θ = 2.7–25.9°
b = 10.718 (2) Å	µ = 0.71 mm^−1
c = 10.759 (2) Å	T = 295 K
β = 101.40 (2)°	Prism, yellow
V = 851.1 (3) Å^3	0.50 × 0.23 × 0.19 mm
Z = 2

Data collection

Stoe IPDS diffractometer	1192 reflections with I > 2σ(I)
Detector resolution: 6.66 pixels mm^-1	Rint = 0.049
Oscillation Phi Incr 2.1 deg scans	θmax = 26.1°, θmin = 2.7°
Absorption correction: gaussian (ABSGAUSS in PLATON; Spek, 2009)	h = −9→9
Tmin = 0.794, Tmax = 0.893	k = −13→13
8137 measured reflections	l = −13→13
1671 independent reflections

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)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.081	H-atom parameters constrained
S = 0.94	w = 1/[σ^2(Fo^2) + (0.0486P)^2] where P = (Fo^2 + 2Fc^2)/3
1671 reflections	(Δ/σ)max < 0.001
110 parameters	Δρmax = 0.19 e Å^−3
0 restraints	Δρmin = −0.15 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
C1	0.4564 (3)	0.03468 (18)	0.0456 (2)	0.0533 (5)
H1A	0.3651	−0.0174	0.0720	0.064*
H1B	0.5464	0.0559	0.1203	0.064*
C3	0.3844 (3)	0.24891 (17)	0.05017 (19)	0.0418 (4)
H3	0.4478	0.2490	0.1336	0.050*
C4	0.3008 (2)	0.36389 (16)	−0.00494 (17)	0.0358 (4)
C5	0.3094 (2)	0.47168 (17)	0.06874 (19)	0.0411 (4)
H5	0.3694	0.4703	0.1530	0.049*
C6	0.2293 (3)	0.57999 (16)	0.0169 (2)	0.0427 (5)
C7	0.1393 (3)	0.58432 (16)	−0.1083 (2)	0.0438 (5)
H7	0.0854	0.6580	−0.1425	0.053*
C8	0.1302 (2)	0.47829 (17)	−0.18167 (18)	0.0409 (4)
C9	0.2103 (2)	0.36623 (15)	−0.13247 (18)	0.0362 (4)
N2	0.3722 (2)	0.14858 (14)	−0.01354 (16)	0.0449 (4)
O9	0.1968 (2)	0.26567 (12)	−0.20694 (13)	0.0479 (3)
H9	0.2404	0.2052	−0.1650	0.072*
Cl6	0.23717 (8)	0.71310 (5)	0.11055 (6)	0.0639 (2)
Cl8	0.01342 (8)	0.47988 (5)	−0.33747 (5)	0.06174 (19)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0655 (14)	0.0390 (10)	0.0563 (14)	0.0175 (9)	0.0141 (10)	0.0124 (9)
C3	0.0446 (10)	0.0426 (10)	0.0388 (10)	0.0057 (8)	0.0094 (8)	0.0054 (8)
C4	0.0348 (9)	0.0336 (9)	0.0398 (10)	0.0016 (7)	0.0093 (8)	0.0025 (8)
C5	0.0406 (10)	0.0405 (10)	0.0424 (11)	−0.0021 (8)	0.0085 (8)	−0.0027 (8)
C6	0.0432 (10)	0.0316 (9)	0.0568 (13)	−0.0051 (8)	0.0183 (9)	−0.0053 (9)
C7	0.0449 (10)	0.0290 (9)	0.0607 (14)	0.0041 (8)	0.0181 (9)	0.0073 (9)
C8	0.0395 (10)	0.0387 (10)	0.0453 (11)	0.0026 (8)	0.0099 (8)	0.0082 (8)
C9	0.0390 (9)	0.0302 (8)	0.0405 (10)	0.0018 (7)	0.0112 (8)	0.0003 (8)
N2	0.0485 (9)	0.0355 (8)	0.0508 (10)	0.0108 (7)	0.0097 (7)	0.0072 (8)
O9	0.0621 (9)	0.0359 (7)	0.0433 (8)	0.0086 (6)	0.0050 (6)	−0.0026 (6)
Cl6	0.0764 (4)	0.0381 (3)	0.0824 (4)	−0.0077 (3)	0.0282 (3)	−0.0184 (3)
Cl8	0.0731 (4)	0.0593 (3)	0.0478 (3)	0.0151 (3)	−0.0003 (2)	0.0117 (3)

Geometric parameters (Å, º)

C1—N2	1.462 (2)	C5—H5	0.9300
C1—C1^i	1.484 (4)	C6—C7	1.383 (3)
C1—H1A	0.9700	C6—Cl6	1.7410 (19)
C1—H1B	0.9700	C7—C8	1.378 (3)
C3—N2	1.269 (2)	C7—H7	0.9300
C3—C4	1.456 (2)	C8—C9	1.400 (2)
C3—H3	0.9300	C8—Cl8	1.732 (2)
C4—C5	1.395 (2)	C9—O9	1.335 (2)
C4—C9	1.406 (3)	O9—H9	0.8200
C5—C6	1.375 (3)
N2—C1—C1^i	109.9 (2)	C5—C6—C7	120.98 (17)
N2—C1—H1A	109.7	C5—C6—Cl6	119.66 (16)
C1^i—C1—H1A	109.7	C7—C6—Cl6	119.34 (14)
N2—C1—H1B	109.7	C8—C7—C6	119.31 (16)
C1^i—C1—H1B	109.7	C8—C7—H7	120.3
H1A—C1—H1B	108.2	C6—C7—H7	120.3
N2—C3—C4	121.22 (18)	C7—C8—C9	121.46 (18)
N2—C3—H3	119.4	C7—C8—Cl8	120.31 (14)
C4—C3—H3	119.4	C9—C8—Cl8	118.21 (15)
C5—C4—C9	119.92 (16)	O9—C9—C8	119.32 (17)
C5—C4—C3	120.11 (17)	O9—C9—C4	122.41 (15)
C9—C4—C3	119.97 (16)	C8—C9—C4	118.26 (16)
C6—C5—C4	120.07 (18)	C3—N2—C1	119.58 (18)
C6—C5—H5	120.0	C9—O9—H9	109.5
C4—C5—H5	120.0
N2—C3—C4—C5	177.24 (17)	C7—C8—C9—O9	179.49 (17)
N2—C3—C4—C9	−2.4 (3)	Cl8—C8—C9—O9	1.1 (2)
C9—C4—C5—C6	0.1 (3)	C7—C8—C9—C4	0.2 (3)
C3—C4—C5—C6	−179.52 (17)	Cl8—C8—C9—C4	−178.22 (13)
C4—C5—C6—C7	0.0 (3)	C5—C4—C9—O9	−179.50 (16)
C4—C5—C6—Cl6	178.76 (13)	C3—C4—C9—O9	0.2 (3)
C5—C6—C7—C8	−0.1 (3)	C5—C4—C9—C8	−0.2 (2)
Cl6—C6—C7—C8	−178.80 (14)	C3—C4—C9—C8	179.41 (16)
C6—C7—C8—C9	−0.1 (3)	C4—C3—N2—C1	−179.34 (17)
C6—C7—C8—Cl8	178.35 (14)	C1^i—C1—N2—C3	−139.3 (3)

Symmetry code: (i) −x+1, −y, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O9—H9···N2	0.82	1.84	2.562 (2)	147