(E,E)-4,4′,6,6′-Tetra­chloro-2,2′-(1,1′-azinodiethyl­ene)diphenol

The title compound, C₁₈H₁₆Cl₄N₂O₂, was synthesized by the reaction of 1-(3,5-dichloro-2-hydroxy­phen­yl)propan-1-one with hydrazine hydrate. The mol­ecule has a centre of symmetry at the mid-point of the N—N bond. The crystal structure is stabilized by intra­molecular O—H...N and inter­molecular C—H...Cl hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 273 K
• Mean [sigma](C-C)= 0.002 Å
• R factor = 0.026
• wR factor = 0.075
• Data-to-parameter ratio = 13.6

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S1. Comment

Recently, a number of azine compounds containing both a diimine linkage and N—N bonding have been investigated in terms of their crystallography and coordination chemistry (Kundu et al., 2005; Kesslen et al., 1999; Zheng et al., 2005;). As an extension of work on the structural characterization of azine derivatives,the title compound, (I),was synthesized and its crystal structure is reported here.

In the title compound, there is a crystallographic centre of symmetry at the midpoint of the N—N bond (Fig. 1.). The molecule displays an (E, E) conformation with respect to the C7=N1 and its symmetry related c7a=N1a double bond (Fig. 1.). This configuration agrees with those commonly found in similar compounds (Glaser et al., 1995; Hunig et al., 2000).The crystal structure is stabilized by intramolecular O—H···N and intermolecular C—H···Cl hydrogen bonds.(Table 1. and Fig. 2).

Related literature

For further details of the chemistry of the title compound, see: Kundu et al. (2005); Kesslen et al. (1999); Zheng et al. (2005); For literature on similar structures, see: Glaser et al. (1995); Hunig et al. (2000).

S2. Experimental

An ethanol solution (50 ml) of hydrazine (0.02 mol) and 1-(3,5-dichloro-2-hydroxyphenyl)propan-1-one (0.04 mol) was refluxed and stirred for 5 h; the mixture was cooled and the resulting solid product, (I), was collected by filtration.Crystals suitable for single-crystal X-ray diffraction were grown by slow evaporation of a solution in 1,2-dichloroethane.

S3. Refinement

All H atoms were positioned geometrically and treated as riding on their parent atoms,with C—H(methyl) = 0.96 Å, C—H(methylene) = 0.97 Å,C—H(aromatic) = 0.93 Å, O—H = 0.82 Å and with U_iso(H) =1.5U_eq(C_methyl,O) and 1.2U_eq(C_aromatic,C_methylene).

Computing details

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. The molecular structure of compound (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. Packing diagram of (I), showing intramolecular O—H···N and intermolecular C—H···Cl hydrogen bonds.(dashed lines).

(E,E)-4,4',6,6'-Tetrachloro-2,2'-(1,1'-azinodiethylene)diphenol

Crystal data

C18H16Cl4N2O2	Z = 1
Mr = 434.13	F(000) = 222
Triclinic, P1	Dx = 1.555 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.8251 (5) Å	Cell parameters from 3274 reflections
b = 8.0294 (4) Å	θ = 0.0–0.0°
c = 8.3899 (5) Å	µ = 0.65 mm^−1
α = 65.894 (2)°	T = 273 K
β = 80.961 (4)°	Plate, yellow
γ = 74.821 (2)°	0.33 × 0.22 × 0.11 mm
V = 463.63 (5) Å^3

Data collection

Bruker APEXII CCD area-detector diffractometer	1635 independent reflections
Radiation source: fine-focus sealed tube	1494 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.018
φ and ω scans	θmax = 25.0°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	h = −8→9
Tmin = 0.813, Tmax = 0.932	k = −9→9
5333 measured reflections	l = −9→9

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)] = 0.026	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.075	H-atom parameters constrained
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0395P)^2 + 0.1214P] where P = (Fo^2 + 2Fc^2)/3
1635 reflections	(Δ/σ)max < 0.001
120 parameters	Δρmax = 0.22 e Å^−3
0 restraints	Δρmin = −0.21 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 F^2^ against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F^2^, conventional R-factors R are based on F, with F set to zero for negative F^2^. The threshold expression of F^2^ > σ(F^2^) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F^2^ 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	0.18719 (6)	−0.14153 (6)	0.90825 (6)	0.05554 (16)
Cl2	0.43014 (6)	0.46317 (6)	0.80112 (7)	0.05983 (17)
O1	0.73361 (16)	0.29828 (16)	0.62779 (17)	0.0504 (3)
H1	0.8185	0.2477	0.5804	0.076*
N1	0.92133 (17)	0.03912 (18)	0.53574 (17)	0.0390 (3)
C1	0.3518 (2)	−0.0141 (2)	0.82541 (19)	0.0372 (3)
C2	0.3274 (2)	0.1548 (2)	0.84262 (19)	0.0396 (4)
H2	0.2247	0.1997	0.8986	0.048*
C3	0.4578 (2)	0.2547 (2)	0.7753 (2)	0.0392 (4)
C4	0.6141 (2)	0.1919 (2)	0.68970 (19)	0.0370 (3)
C5	0.63793 (19)	0.0177 (2)	0.67474 (18)	0.0336 (3)
C6	0.5032 (2)	−0.0823 (2)	0.74394 (19)	0.0365 (3)
H6	0.5167	−0.1966	0.7345	0.044*
C7	0.80203 (19)	−0.0610 (2)	0.59174 (18)	0.0345 (3)
C8	0.8265 (2)	−0.2498 (2)	0.5844 (2)	0.0400 (4)
H8A	0.9018	−0.2539	0.4819	0.048*
H8B	0.7123	−0.2690	0.5733	0.048*
C9	0.9097 (3)	−0.4059 (2)	0.7471 (3)	0.0615 (5)
H9A	1.0241	−0.3890	0.7568	0.092*
H9B	0.9227	−0.5244	0.7387	0.092*
H9C	0.8348	−0.4029	0.8487	0.092*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0414 (2)	0.0580 (3)	0.0741 (3)	−0.02249 (19)	0.0186 (2)	−0.0330 (2)
Cl2	0.0591 (3)	0.0465 (3)	0.0872 (4)	−0.0123 (2)	0.0113 (2)	−0.0441 (2)
O1	0.0486 (7)	0.0448 (6)	0.0683 (8)	−0.0217 (5)	0.0167 (6)	−0.0323 (6)
N1	0.0353 (7)	0.0386 (7)	0.0457 (7)	−0.0114 (5)	0.0096 (5)	−0.0209 (6)
C1	0.0338 (8)	0.0399 (8)	0.0384 (8)	−0.0107 (6)	0.0030 (6)	−0.0159 (6)
C2	0.0358 (8)	0.0425 (8)	0.0414 (8)	−0.0042 (6)	0.0023 (6)	−0.0214 (7)
C3	0.0423 (8)	0.0353 (8)	0.0446 (8)	−0.0062 (6)	−0.0005 (7)	−0.0220 (7)
C4	0.0397 (8)	0.0350 (7)	0.0390 (8)	−0.0109 (6)	0.0010 (6)	−0.0166 (6)
C5	0.0340 (8)	0.0347 (7)	0.0330 (7)	−0.0083 (6)	0.0026 (6)	−0.0150 (6)
C6	0.0387 (8)	0.0337 (7)	0.0406 (8)	−0.0109 (6)	0.0021 (6)	−0.0175 (6)
C7	0.0363 (8)	0.0352 (7)	0.0339 (7)	−0.0102 (6)	0.0017 (6)	−0.0152 (6)
C8	0.0352 (8)	0.0424 (8)	0.0505 (9)	−0.0118 (6)	0.0080 (6)	−0.0276 (7)
C9	0.0623 (12)	0.0390 (9)	0.0791 (13)	−0.0084 (8)	−0.0086 (10)	−0.0184 (9)

Geometric parameters (Å, º)

Cl1—C1	1.7372 (15)	C4—C5	1.416 (2)
Cl2—C3	1.7281 (15)	C5—C6	1.401 (2)
O1—C4	1.3331 (18)	C5—C7	1.479 (2)
O1—H1	0.8200	C6—H6	0.9300
N1—C7	1.2980 (19)	C7—C8	1.503 (2)
N1—N1^i	1.393 (2)	C8—C9	1.521 (2)
C1—C6	1.372 (2)	C8—H8A	0.9700
C1—C2	1.383 (2)	C8—H8B	0.9700
C2—C3	1.372 (2)	C9—H9A	0.9600
C2—H2	0.9300	C9—H9B	0.9600
C3—C4	1.402 (2)	C9—H9C	0.9600
C4—O1—H1	109.5	C1—C6—H6	119.5
C7—N1—N1^i	115.44 (15)	C5—C6—H6	119.5
C6—C1—C2	121.22 (13)	N1—C7—C5	115.61 (13)
C6—C1—Cl1	119.55 (12)	N1—C7—C8	124.08 (13)
C2—C1—Cl1	119.22 (12)	C5—C7—C8	120.24 (12)
C3—C2—C1	118.61 (14)	C7—C8—C9	111.55 (13)
C3—C2—H2	120.7	C7—C8—H8A	109.3
C1—C2—H2	120.7	C9—C8—H8A	109.3
C2—C3—C4	122.34 (13)	C7—C8—H8B	109.3
C2—C3—Cl2	118.75 (12)	C9—C8—H8B	109.3
C4—C3—Cl2	118.89 (12)	H8A—C8—H8B	108.0
O1—C4—C3	118.32 (13)	C8—C9—H9A	109.5
O1—C4—C5	123.32 (14)	C8—C9—H9B	109.5
C3—C4—C5	118.35 (13)	H9A—C9—H9B	109.5
C6—C5—C4	118.54 (13)	C8—C9—H9C	109.5
C6—C5—C7	119.96 (13)	H9A—C9—H9C	109.5
C4—C5—C7	121.48 (13)	H9B—C9—H9C	109.5
C1—C6—C5	120.93 (14)
C6—C1—C2—C3	0.4 (2)	C2—C1—C6—C5	−0.3 (2)
Cl1—C1—C2—C3	−179.48 (11)	Cl1—C1—C6—C5	179.58 (11)
C1—C2—C3—C4	0.2 (2)	C4—C5—C6—C1	−0.4 (2)
C1—C2—C3—Cl2	−178.49 (12)	C7—C5—C6—C1	178.35 (13)
C2—C3—C4—O1	179.77 (14)	N1^i—N1—C7—C5	177.43 (14)
Cl2—C3—C4—O1	−1.6 (2)	N1^i—N1—C7—C8	0.6 (3)
C2—C3—C4—C5	−0.8 (2)	C6—C5—C7—N1	−178.17 (13)
Cl2—C3—C4—C5	177.85 (11)	C4—C5—C7—N1	0.5 (2)
O1—C4—C5—C6	−179.73 (13)	C6—C5—C7—C8	−1.2 (2)
C3—C4—C5—C6	0.9 (2)	C4—C5—C7—C8	177.50 (13)
O1—C4—C5—C7	1.6 (2)	N1—C7—C8—C9	88.61 (19)
C3—C4—C5—C7	−177.81 (13)	C5—C7—C8—C9	−88.11 (18)

Symmetry code: (i) −x+2, −y, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N1	0.82	1.82	2.538 (1)	146
C6—H6···Cl2^ii	0.93	2.80	3.6678 (15)	156

Symmetry code: (ii) x, y−1, z.