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Acta Cryst. (2009). E65, o2153    [ doi:10.1107/S1600536809031298 ]

(Z)-6-[(5-Chloro-2-hydroxyphenyl)aminomethylene]-2-ethoxycyclohexa-2,4-dienone

A. Özek, Ç. Albayrak and O. Büyükgüngör

Abstract top

The title compound, C15H14ClNO3, exists as the keto-amine form in the crystal and two intramolecular N-H...O hydrogen bonds are observed. The aromatic rings are oriented at a dihedral angle of 5.85 (8)°. In the crystal structure, intermolecular O-H...O and C-H...O hydrogen bonds link the molecules into chains. A [pi]-[pi] contact between the benzene rings [centroid-centroid distance = 3.6623 (10) Å] further stabilizes the structure.

Comment top

As part of our ongoing studies on the syntheses and structural characterizations of Schiff-base compounds (Özek et al., 2008; Özek et al., 2007), we report here in the crystal structure of the title compound.

Schiff bases display two possible tautomeric forms, namely phenol-imine (O—H···N) and keto-amine (N—H···O) forms. o-Hydroxy Schiff bases have previously been observed in the keto form (Tanak et al., 2008) and in the enol form (Büyükgüngör et al., 2007).

The H atom in title compound (I) is located on atom N1, thus the keto-amine tautomer is favored over the phenol-imine form, as indicated by C2—O1 [1.279 (2) Å], C9—N1 [1.310 (2) Å], C1—C9 [1.410 (2) Å] and C1—C2 [1.432 (2) Å] bonds (Fig. 1). The O1—C2 bond length of 1.279 (2) Å indicates double-bond character, whereas the N1—C9 bond length of 1.310 (2) Å indicates a high degree of single-bond character. Similar results were observed for 2-[(2-Hydroxy- 4-nitrophenyl)-aminomethylene]cyclohexa-3,5-dien-1(2H)-οne [C—O = 1.298 (2) and C—N =1.308 (2) Å; Ersanlı et al., 2003].

It is known that Schiff bases may exhibit thermochromism or photochromism, depending on the planarity or non-planarity of the molecule, respectively. Therefore, one can expect thermochromic properties in the title compound caused by planarity of the molecule; the dihedral angle between rings A (C1—C6) and B (C10—C15) is 5.85 (8)°. Intramolecular N—H···O hydrogen bonds (Table 1) result in the formations of planar six- and five-membered rings C (O1/N1/C1/C2/C9/H1) and D (O3/N1/C10/C11/H1). They are oriented with respect to the adjacent rings at dihedral angles of A/C = 1.65 (9), A/D = 5.12 (9), B/C = 7.29 (7), B/D = 4.51 (5) and C/D = 5.61 (12) °. So, they are nearly coplanar.

In the crystal structure, molecules are linked into a three-dimensional network by intermolecular C—H···O and O—H···O hyrogen bonds (Table 1). The C—H···O hydrogen bonds generate C(6) chains along the c axis and O—H···O hydrogen bonds generate R22(18) ring motif (Fig. 2). The π···π contact between the phenyl rings, Cg1—Cg2i [symmetry code: (i) 1 - x, 1/2 + y, 1/2 - z, where Cg1 and Cg2 are centroids of the rings A (C1—C6) and B (C10—C15), respectively] may further stabilize the structure, with centroid-centroid distance of 3.6623 (10) Å.

Related literature top

For general background, see: Büyükgüngör et al. (2007); Ersanlı et al. (2003); Tanak et al. (2008) For related structures, see: Özek et al. (2007, 2008).

Experimental top

The compound (Z)-6-[(5-chloro-2-hydroxyphenylamino)methylene]-2- ethoxycyclohexa-2,4-dienone was prepared by reflux a mixture of a solution containing 3-ethoxy-2-hydroxybenzaldehyde (0.5 g 3 mmol) in 20 ml e thanol and a solution containing 5-chloro-2-hydroxyaniline (0.43 g 3 mmol) in 20 ml e thanol. The reaction mixture was stirred for 1 h under reflux. The crystals of (Z)-6-[(5-chloro-2-hydroxyphenylamino) methylene]-2-ethoxycyclohexa-2,4-dienone suitable for X-ray analysis were obtained from ethanol by slow evaporation (yield % 89; m.p. 489–491 K).

Refinement top

H atoms were located in difference synthesis, and refined freely.

Computing details top

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. A view of (I), with the atom-numbering scheme and 30% probability displacement ellipsoids. Dashed line indicates intramolecular hydrogen bond.
[Figure 2] Fig. 2. A partial packing view of (I), showing the intermolecular C—H···O and O—H···O hydrogen bonds. Dashed lines indicate hydrogen bonds. H atoms are represented as small spheres of arbitrary radii and H atoms not involved in hydrogen bonding have been omitted for clarity. [Symmetry codes: (i): x, -y + 1/2, z + 1/2; (ii): 1 - x, -y, 1 - z].
(Z)-6-[(5-Chloro-2-hydroxyphenyl)aminomethylene]-2-ethoxycyclohexa-2,4- dienone top
Crystal data top
C15H14ClNO3F(000) = 608
Mr = 291.72Dx = 1.489 Mg m−3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 15989 reflections
a = 15.4313 (7) Åθ = 2.8–26.5°
b = 7.1710 (2) ŵ = 0.30 mm−1
c = 12.6071 (6) ÅT = 296 K
β = 111.168 (4)°Prism, red
V = 1300.94 (10) Å30.52 × 0.29 × 0.09 mm
Z = 4
Data collection top
STOE IPDS II
diffractometer		2680 independent reflections
Radiation source: fine-focus sealed tube2084 reflections with I > 2σ(I)
plane graphiteRint = 0.060
Detector resolution: 6.67 pixels mm-1θmax = 26.5°, θmin = 2.8°
ω scansh = −19→19
Absorption correction: integration
X-RED32 (Stoe & Cie, 2002)		k = −8→8
Tmin = 0.616, Tmax = 0.927l = −15→15
15989 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.041Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.099All H-atom parameters refined
S = 1.05 w = 1/[σ2(Fo2) + (0.0546P)2 + 0.0402P]
where P = (Fo2 + 2Fc2)/3
2680 reflections(Δ/σ)max < 0.001
237 parametersΔρmax = 0.14 e Å−3
0 restraintsΔρmin = −0.25 e Å−3
Crystal data top
C15H14ClNO3V = 1300.94 (10) Å3
Mr = 291.72Z = 4
Monoclinic, P21/cMo Kα radiation
a = 15.4313 (7) ŵ = 0.30 mm−1
b = 7.1710 (2) ÅT = 296 K
c = 12.6071 (6) Å0.52 × 0.29 × 0.09 mm
β = 111.168 (4)°
Data collection top
STOE IPDS II
diffractometer		2680 independent reflections
Absorption correction: integration
X-RED32 (Stoe & Cie, 2002)		2084 reflections with I > 2σ(I)
Tmin = 0.616, Tmax = 0.927Rint = 0.060
15989 measured reflectionsθmax = 26.5°
Refinement top
R[F2 > 2σ(F2)] = 0.041All H-atom parameters refined
wR(F2) = 0.099Δρmax = 0.14 e Å−3
S = 1.05Δρmin = −0.25 e Å−3
2680 reflectionsAbsolute structure: ?
237 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Experimental. 314 frames, detector distance = 100 mm

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 (Å2) top
xyzUiso*/Ueq
C10.42045 (11)0.1210 (2)0.12588 (13)0.0348 (3)
C20.35762 (11)0.0951 (2)0.18490 (13)0.0347 (3)
C30.25975 (11)0.0968 (2)0.11617 (14)0.0354 (4)
C40.23136 (12)0.1153 (2)0.00038 (14)0.0405 (4)
C50.29497 (13)0.1391 (3)−0.05529 (15)0.0420 (4)
C60.38735 (12)0.1431 (2)0.00582 (14)0.0397 (4)
C70.10537 (12)0.1023 (3)0.11398 (16)0.0429 (4)
C80.05590 (13)0.1030 (4)0.19698 (19)0.0515 (5)
C90.51704 (11)0.1302 (2)0.18651 (15)0.0372 (4)
C100.65028 (11)0.1159 (2)0.36438 (14)0.0349 (3)
C110.67292 (11)0.1056 (2)0.48215 (14)0.0366 (4)
C120.76552 (12)0.0967 (3)0.55291 (16)0.0435 (4)
C130.83466 (12)0.0983 (3)0.50765 (16)0.0446 (4)
C140.81081 (11)0.1101 (2)0.39143 (16)0.0398 (4)
C150.71950 (12)0.1205 (2)0.31875 (15)0.0385 (4)
N10.55488 (9)0.1157 (2)0.29736 (12)0.0375 (3)
O10.38649 (8)0.07391 (19)0.29284 (10)0.0458 (3)
O20.20269 (8)0.08261 (18)0.17686 (10)0.0432 (3)
O30.60157 (9)0.10408 (19)0.52038 (11)0.0462 (3)
Cl10.89826 (3)0.10870 (7)0.33413 (5)0.05476 (17)
H10.5154 (16)0.095 (3)0.3294 (19)0.057 (6)*
H30.6156 (16)0.048 (3)0.584 (2)0.058 (6)*
H40.1662 (17)0.112 (3)−0.044 (2)0.067 (7)*
H50.2700 (13)0.157 (3)−0.1342 (18)0.048 (5)*
H60.4309 (14)0.169 (3)−0.0299 (16)0.047 (5)*
H7A0.0925 (14)0.221 (3)0.0713 (18)0.055 (6)*
H7B0.0851 (14)−0.005 (3)0.0600 (18)0.049 (5)*
H8A0.0771 (17)0.197 (3)0.250 (2)0.067 (7)*
H8B0.0646 (15)−0.015 (4)0.2363 (19)0.063 (6)*
H8C−0.0076 (18)0.120 (3)0.157 (2)0.068 (7)*
H90.5538 (13)0.150 (2)0.1399 (16)0.041 (5)*
H120.7798 (15)0.087 (3)0.633 (2)0.055 (6)*
H130.8974 (15)0.090 (3)0.5585 (18)0.053 (6)*
H150.7051 (13)0.124 (3)0.2410 (18)0.046 (5)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0326 (8)0.0412 (8)0.0316 (8)0.0001 (7)0.0127 (6)−0.0005 (7)
C20.0332 (8)0.0416 (8)0.0302 (8)0.0009 (7)0.0124 (6)0.0021 (6)
C30.0329 (8)0.0404 (8)0.0331 (8)−0.0007 (7)0.0122 (6)−0.0005 (7)
C40.0356 (8)0.0490 (9)0.0333 (8)0.0003 (7)0.0081 (7)−0.0003 (7)
C50.0454 (10)0.0520 (11)0.0264 (8)0.0044 (8)0.0103 (7)0.0021 (7)
C60.0425 (9)0.0470 (10)0.0344 (9)0.0034 (7)0.0197 (7)0.0042 (7)
C70.0294 (8)0.0547 (11)0.0421 (9)0.0028 (8)0.0099 (7)0.0023 (9)
C80.0334 (9)0.0712 (14)0.0510 (11)0.0059 (9)0.0167 (9)0.0038 (11)
C90.0349 (8)0.0439 (9)0.0368 (8)−0.0001 (7)0.0178 (7)0.0027 (7)
C100.0298 (7)0.0389 (8)0.0367 (9)−0.0004 (6)0.0129 (6)0.0021 (7)
C110.0352 (8)0.0407 (8)0.0373 (8)0.0004 (7)0.0172 (7)0.0021 (7)
C120.0382 (9)0.0533 (10)0.0365 (9)0.0016 (8)0.0102 (7)0.0024 (8)
C130.0312 (8)0.0510 (10)0.0475 (10)0.0006 (7)0.0091 (7)0.0016 (8)
C140.0313 (8)0.0409 (9)0.0511 (10)−0.0009 (7)0.0197 (7)0.0017 (8)
C150.0361 (8)0.0447 (9)0.0383 (9)0.0008 (7)0.0178 (7)0.0007 (7)
N10.0295 (7)0.0513 (8)0.0334 (7)−0.0013 (6)0.0136 (6)0.0017 (6)
O10.0332 (6)0.0767 (9)0.0287 (6)−0.0018 (6)0.0125 (5)0.0055 (6)
O20.0277 (6)0.0683 (8)0.0333 (6)−0.0003 (5)0.0107 (5)0.0035 (5)
O30.0403 (7)0.0646 (8)0.0403 (7)0.0069 (6)0.0225 (6)0.0103 (6)
Cl10.0386 (2)0.0643 (3)0.0721 (3)0.0028 (2)0.0328 (2)0.0067 (2)
Geometric parameters (Å, °) top
C1—C91.410 (2)C8—H8C0.93 (3)
C1—C61.421 (2)C9—N11.310 (2)
C1—C21.432 (2)C9—H90.96 (2)
C2—O11.279 (2)C10—C151.384 (2)
C2—C31.445 (2)C10—C111.399 (2)
C3—O21.363 (2)C10—N11.408 (2)
C3—C41.371 (2)C11—O31.3519 (19)
C4—C51.408 (3)C11—C121.386 (2)
C4—H40.96 (2)C12—C131.380 (3)
C5—C61.354 (2)C12—H120.95 (2)
C5—H50.94 (2)C13—C141.378 (3)
C6—H60.95 (2)C13—H130.95 (2)
C7—O21.430 (2)C14—C151.378 (2)
C7—C81.502 (3)C14—Cl11.7456 (17)
C7—H7A0.99 (2)C15—H150.92 (2)
C7—H7B1.00 (2)N1—H10.86 (2)
C8—H8A0.92 (2)O3—H30.85 (2)
C8—H8B0.97 (2)
C9—C1—C6118.39 (15)H8A—C8—H8C109 (2)
C9—C1—C2120.41 (15)H8B—C8—H8C108.4 (19)
C6—C1—C2121.18 (14)N1—C9—C1123.47 (15)
O1—C2—C1121.83 (14)N1—C9—H9121.9 (11)
O1—C2—C3121.77 (14)C1—C9—H9114.6 (11)
C1—C2—C3116.40 (14)C15—C10—C11120.52 (15)
O2—C3—C4125.61 (15)C15—C10—N1123.16 (15)
O2—C3—C2114.20 (14)C11—C10—N1116.29 (14)
C4—C3—C2120.18 (15)O3—C11—C12123.59 (16)
C3—C4—C5122.02 (16)O3—C11—C10117.09 (15)
C3—C4—H4118.9 (14)C12—C11—C10119.32 (15)
C5—C4—H4119.0 (14)C13—C12—C11120.32 (17)
C6—C5—C4119.94 (16)C13—C12—H12121.3 (13)
C6—C5—H5123.1 (12)C11—C12—H12118.4 (13)
C4—C5—H5116.9 (12)C14—C13—C12119.38 (16)
C5—C6—C1120.23 (16)C14—C13—H13122.5 (13)
C5—C6—H6120.8 (12)C12—C13—H13118.1 (13)
C1—C6—H6118.8 (12)C15—C14—C13121.78 (16)
O2—C7—C8108.09 (15)C15—C14—Cl1118.87 (14)
O2—C7—H7A110.6 (12)C13—C14—Cl1119.34 (13)
C8—C7—H7A108.8 (12)C14—C15—C10118.66 (16)
O2—C7—H7B108.1 (12)C14—C15—H15120.2 (12)
C8—C7—H7B111.4 (12)C10—C15—H15121.0 (12)
H7A—C7—H7B109.8 (17)C9—N1—C10127.35 (15)
C7—C8—H8A111.7 (15)C9—N1—H1113.4 (15)
C7—C8—H8B110.1 (14)C10—N1—H1119.0 (15)
H8A—C8—H8B109 (2)C3—O2—C7116.33 (13)
C7—C8—H8C109.0 (15)C11—O3—H3112.0 (16)
C9—C1—C2—O1−2.2 (3)C15—C10—C11—C12−1.1 (3)
C6—C1—C2—O1179.60 (16)N1—C10—C11—C12177.13 (16)
C9—C1—C2—C3176.96 (15)O3—C11—C12—C13179.80 (17)
C6—C1—C2—C3−1.3 (2)C10—C11—C12—C130.1 (3)
O1—C2—C3—O22.8 (2)C11—C12—C13—C140.5 (3)
C1—C2—C3—O2−176.34 (14)C12—C13—C14—C150.0 (3)
O1—C2—C3—C4−178.42 (16)C12—C13—C14—Cl1−179.07 (14)
C1—C2—C3—C42.5 (2)C13—C14—C15—C10−1.0 (3)
O2—C3—C4—C5176.54 (16)Cl1—C14—C15—C10178.08 (13)
C2—C3—C4—C5−2.1 (3)C11—C10—C15—C141.5 (3)
C3—C4—C5—C60.4 (3)N1—C10—C15—C14−176.58 (16)
C4—C5—C6—C10.8 (3)C1—C9—N1—C10177.28 (17)
C9—C1—C6—C5−178.59 (17)C15—C10—N1—C9−4.2 (3)
C2—C1—C6—C5−0.3 (3)C11—C10—N1—C9177.63 (17)
C6—C1—C9—N1178.49 (16)C4—C3—O2—C7−4.7 (2)
C2—C1—C9—N10.2 (3)C2—C3—O2—C7174.00 (15)
C15—C10—C11—O3179.17 (15)C8—C7—O2—C3−174.00 (16)
N1—C10—C11—O3−2.6 (2)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O10.86 (2)1.88 (2)2.5957 (17)140 (2)
N1—H1···O30.86 (2)2.29 (2)2.640 (2)104.3 (17)
O3—H3···O1i0.85 (2)1.79 (2)2.6258 (17)165 (2)
C9—H9···O3ii0.96 (2)2.594 (19)3.419 (2)143.8 (14)
Symmetry codes: (i) −x+1, −y, −z+1; (ii) x, −y+1/2, z−1/2.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O10.86 (2)1.88 (2)2.5957 (17)140 (2)
N1—H1···O30.86 (2)2.29 (2)2.640 (2)104.3 (17)
O3—H3···O1i0.85 (2)1.79 (2)2.6258 (17)165 (2)
C9—H9···O3ii0.96 (2)2.594 (19)3.419 (2)143.8 (14)
Symmetry codes: (i) −x+1, −y, −z+1; (ii) x, −y+1/2, z−1/2.
Acknowledgements top

The authors acknowledge the Faculty of Arts and Sciences, Ondokuz Mayıs University, Turkey, for the use of the Stoe IPDS II diffractometer (purchased under grant No. F.279 of the University Research Fund).

references
References top

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