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Acta Crystallogr Sect E Struct Rep Online. 2009 November 1; 65(Pt 11): o2695.
Published online 2009 October 10. doi:  10.1107/S1600536809040240
PMCID: PMC2971457

2-[(4-Ethoxy­phen­yl)imino­meth­yl]-5-methoxy­phenol

Abstract

The title compound, C16H17NO3, a Schiff base, is stabilized in the solid state in the phenol–imine tautomeric form, with the H atom located on the hydr­oxy O atom rather than on the N atom. This H atom is involved in a strong intra­molecular O—H(...)N hydrogen bond. The mol­ecule is almost planar, the angle between the benzene rings being 4.43 (13)°. C—H(...)π inter­actions are also present.

Related literature

For the industrial and biological properties of Schiff bases, see: Karia et al. (1999 [triangle]); Taggi et al. (2002 [triangle]). For Schiff base tautomerism, see: Şahin et al. (2005 [triangle]); Hadjoudis et al. (1987 [triangle]).

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Object name is e-65-o2695-scheme1.jpg

Experimental

Crystal data

  • C16H17NO3
  • M r = 271.31
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-o2695-efi1.jpg
  • a = 7.4609 (7) Å
  • b = 8.3777 (5) Å
  • c = 23.016 (2) Å
  • β = 98.896 (8)°
  • V = 1421.3 (2) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.09 mm−1
  • T = 296 K
  • 0.49 × 0.28 × 0.07 mm

Data collection

  • Stoe IPDS-II diffractometer
  • Absorption correction: integration (X-RED32; Stoe & Cie, 2002 [triangle]) T min = 0.983, T max = 0.994
  • 8971 measured reflections
  • 2788 independent reflections
  • 971 reflections with I > 2σ(I)
  • R int = 0.068

Refinement

  • R[F 2 > 2σ(F 2)] = 0.042
  • wR(F 2) = 0.075
  • S = 0.80
  • 2788 reflections
  • 181 parameters
  • 6 restraints
  • H-atom parameters constrained
  • Δρmax = 0.06 e Å−3
  • Δρmin = −0.09 e Å−3

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

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809040240/bh2250sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809040240/bh2250Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

The authors wish to acknowledge the Faculty of Arts and Sciences, Ondokuz Mayıs University, Turkey, for the use of the Stoe IPDS-II diffractometer (purchased under grant No. F279 of the University Research Fund).

supplementary crystallographic information

Comment

Schiff bases are used as substrates in the preparation of a number of industrial and biologically active compounds via ring closure, cycloaddition and replacement reactions (Karia et al., 1999). Moreover, Schiff bases are also known to have biological activities such as antimicrobial, antifungal, antitumor and as herbicides. On the industrial scale, they have a wide range of applications such as dyes and pigments (Taggi et al., 2002). In general, Schiff bases display two possible tautomeric forms, the phenol-imine (Hadjoudis et al., 1987) and keto-amine (Şahin et al., 2005) forms. Depending on the tautomers two types of intramolecular hydrogen bonds are observed in Schiff bases: O—H···N in phenol-imine and N—H···O in keto-amine tautomers. Our X-ray investigation of the title compound indicates that the phenol-imine tautomer is favoured over the keto-amine tautomer (Fig. 1).

Selected bond lengths of the title compound are given in Table 1. The N1—C8 bond length of 1.285 (3) Å is typical of a double bond. The dihedral angle between the C2···C7 and C9···C14 benzene rings is 4.43 (13)° and the compound is thus almost planar. The C5—C8—N1—C9 torsion angle is 179.3 (2)°. The compound shows a strong intramolecular hydrogen bond (O1—H1···N1) which forms a S(6) motif. The compound also contains five intermolecular C—H···π interactions. The combination of three C—H···π interactions generates chain of edge-fused R21(7)R22(15) rings running parallel to the [010] direction (Fig. 2). The details of C—H···π interactions are given in Table 2.

Experimental

The title compound was prepared by refluxing a mixture of a solution containing 2-hydroxy-4-methoxy-benzaldehyde (0.0237 g, 0.156 mmol) in 20 ml ethanol and a solution containing 4-ethoxyaniline (0.0214 g, 0.156 mmol) in 20 ml ethanol. The reaction mixture was stirred for 1 h under reflux. Crystals suitable for X-ray analysis were obtained from ethylalcohol by slow evaporation (yield % 71; m.p. 381–383 K).

Refinement

Phenolic H atom (H1) was first detected in a difference map, but eventually fixed in calculated position, with the O—H bond length constrained to 0.82 Å and Uiso(H1) = 1.5Ueq(O1). Other H atoms were also placed in calculated positions and constrained to ride on their parents atoms, with C—H = 0.93–0.96 Å, and Uiso(H) = 1.2Ueq(C) or 1.5Ueq(C). For atom C12, anisotropic displacement parameters were restrained to approximate an isotropic behaviour.

Figures

Fig. 1.
The molecular structure of the title compound, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
Fig. 2.
Part of the crystal structure of the title compound, showing the formation of a chain along [010] generated by the C—H···π interactions.

Crystal data

C16H17NO3F(000) = 576
Mr = 271.31Dx = 1.268 Mg m3
Monoclinic, P21/cMelting point: 381 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 7.4609 (7) ÅCell parameters from 5881 reflections
b = 8.3777 (5) Åθ = 1.8–27.3°
c = 23.016 (2) ŵ = 0.09 mm1
β = 98.896 (8)°T = 296 K
V = 1421.3 (2) Å3Plate, yellow
Z = 40.49 × 0.28 × 0.07 mm

Data collection

Stoe IPDS-II diffractometer2788 independent reflections
Radiation source: fine-focus sealed tube971 reflections with I > 2σ(I)
graphiteRint = 0.068
Detector resolution: 6.67 pixels mm-1θmax = 26.0°, θmin = 1.8°
ω scansh = −8→9
Absorption correction: integration (X-RED32; Stoe & Cie, 2002)k = −8→10
Tmin = 0.983, Tmax = 0.994l = −28→28
8971 measured reflections

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.042Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.075H-atom parameters constrained
S = 0.80w = 1/[σ2(Fo2) + (0.0187P)2] where P = (Fo2 + 2Fc2)/3
2788 reflections(Δ/σ)max < 0.001
181 parametersΔρmax = 0.06 e Å3
6 restraintsΔρmin = −0.09 e Å3
0 constraints

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)

xyzUiso*/Ueq
C1−0.6165 (4)0.5043 (3)0.57051 (10)0.1085 (9)
H1A−0.56960.61080.56970.163*
H1B−0.64830.48280.60860.163*
H1C−0.72220.49380.54110.163*
C2−0.3202 (4)0.3896 (3)0.59654 (12)0.0808 (7)
C3−0.2831 (4)0.4771 (3)0.64744 (12)0.0856 (8)
H3−0.36930.54650.65840.103*
C4−0.1155 (5)0.4605 (3)0.68216 (11)0.0800 (7)
C50.0154 (4)0.3552 (3)0.66750 (11)0.0757 (7)
C6−0.0289 (4)0.2690 (3)0.61528 (12)0.0893 (8)
H60.05570.19800.60440.107*
C7−0.1921 (4)0.2855 (3)0.57975 (11)0.0870 (8)
H7−0.21730.22810.54490.104*
C80.1875 (4)0.3370 (3)0.70488 (12)0.0838 (8)
H80.26930.26120.69530.101*
C90.3994 (5)0.4049 (3)0.78873 (12)0.0795 (7)
C100.4158 (4)0.4914 (3)0.84077 (13)0.0890 (8)
H100.32020.55560.84830.107*
C110.5712 (5)0.4833 (3)0.88123 (12)0.0910 (8)
H110.57930.54230.91580.109*
C120.7163 (4)0.3890 (3)0.87168 (12)0.0808 (7)
C130.7025 (4)0.3066 (3)0.81961 (12)0.0921 (8)
H130.79970.24520.81170.111*
C140.5468 (5)0.3141 (3)0.77915 (12)0.0936 (8)
H140.54030.25640.74440.112*
O30.8627 (3)0.38748 (19)0.91485 (8)0.0937 (5)
C161.0174 (4)0.2954 (3)0.90641 (11)0.0995 (8)
H16A1.06450.33240.87180.119*
H16B0.98410.18390.90080.119*
C171.1580 (4)0.3138 (3)0.95957 (11)0.1148 (10)
H17A1.26370.25320.95460.172*
H17B1.11080.27580.99350.172*
H17C1.19000.42450.96490.172*
N10.2308 (3)0.4230 (2)0.75114 (10)0.0830 (6)
O1−0.0840 (2)0.55210 (18)0.73075 (7)0.1034 (6)
H10.01750.53280.74860.155*
O2−0.4817 (3)0.39332 (19)0.55872 (7)0.0959 (5)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
C10.104 (2)0.111 (2)0.119 (2)0.008 (2)0.0432 (17)−0.0031 (16)
C20.101 (3)0.0615 (16)0.086 (2)0.0006 (18)0.0332 (17)0.0117 (15)
C30.113 (3)0.0661 (17)0.0850 (18)−0.0012 (17)0.0390 (17)−0.0099 (15)
C40.110 (2)0.0633 (16)0.0734 (18)−0.0098 (18)0.0350 (17)−0.0052 (14)
C50.107 (3)0.0510 (15)0.0770 (18)0.0034 (16)0.0393 (17)0.0008 (13)
C60.128 (3)0.0612 (16)0.0856 (19)0.0098 (17)0.0385 (17)0.0017 (15)
C70.122 (3)0.0655 (17)0.0777 (18)0.0055 (18)0.0277 (18)−0.0040 (13)
C80.110 (3)0.0594 (16)0.0882 (18)0.0026 (16)0.0367 (17)0.0105 (15)
C90.113 (3)0.0539 (16)0.0788 (19)−0.0098 (17)0.0378 (18)−0.0004 (14)
C100.095 (2)0.0694 (17)0.109 (2)−0.0008 (16)0.0387 (17)−0.0109 (16)
C110.106 (2)0.0722 (18)0.103 (2)−0.0002 (19)0.0425 (18)−0.0223 (15)
C120.104 (3)0.0599 (16)0.0849 (19)−0.0066 (17)0.0352 (18)−0.0046 (14)
C130.107 (3)0.0849 (19)0.090 (2)0.0093 (18)0.0337 (17)−0.0042 (16)
C140.126 (3)0.0754 (18)0.089 (2)0.009 (2)0.044 (2)−0.0130 (15)
O30.0995 (16)0.0828 (12)0.1030 (13)0.0054 (11)0.0288 (12)−0.0143 (9)
C160.106 (3)0.0844 (18)0.117 (2)0.0038 (18)0.0463 (19)−0.0041 (15)
C170.120 (3)0.118 (2)0.107 (2)0.0166 (19)0.0188 (19)0.0062 (16)
N10.111 (2)0.0614 (13)0.0824 (16)−0.0081 (13)0.0317 (14)−0.0039 (11)
O10.1215 (16)0.0934 (12)0.0997 (12)0.0025 (11)0.0312 (10)−0.0327 (10)
O20.1132 (17)0.0798 (12)0.0985 (13)0.0076 (12)0.0283 (12)−0.0057 (9)

Geometric parameters (Å, °)

C1—O21.426 (3)C9—C101.389 (3)
C1—H1A0.9600C9—N11.420 (3)
C1—H1B0.9600C10—C111.372 (3)
C1—H1C0.9600C10—H100.9300
C2—O21.374 (3)C11—C121.385 (3)
C2—C31.374 (3)C11—H110.9300
C2—C71.392 (3)C12—O31.358 (3)
C3—C41.383 (3)C12—C131.373 (3)
C3—H30.9300C13—C141.373 (3)
C4—O11.347 (2)C13—H130.9300
C4—C51.396 (3)C14—H140.9300
C5—C61.398 (3)O3—C161.426 (3)
C5—C81.439 (3)C16—C171.492 (3)
C6—C71.364 (3)C16—H16A0.9700
C6—H60.9300C16—H16B0.9700
C7—H70.9300C17—H17A0.9600
C8—N11.285 (3)C17—H17B0.9600
C8—H80.9300C17—H17C0.9600
C9—C141.383 (3)O1—H10.8200
O2—C1—H1A109.5C11—C10—H10119.6
O2—C1—H1B109.5C9—C10—H10119.6
H1A—C1—H1B109.5C10—C11—C12121.3 (3)
O2—C1—H1C109.5C10—C11—H11119.3
H1A—C1—H1C109.5C12—C11—H11119.3
H1B—C1—H1C109.5O3—C12—C13125.3 (3)
O2—C2—C3124.7 (3)O3—C12—C11116.7 (3)
O2—C2—C7114.3 (3)C13—C12—C11118.1 (3)
C3—C2—C7121.0 (3)C12—C13—C14120.7 (3)
C2—C3—C4118.9 (3)C12—C13—H13119.6
C2—C3—H3120.5C14—C13—H13119.6
C4—C3—H3120.5C13—C14—C9121.8 (3)
O1—C4—C3116.6 (3)C13—C14—H14119.1
O1—C4—C5121.5 (3)C9—C14—H14119.1
C3—C4—C5121.9 (3)C12—O3—C16118.8 (2)
C4—C5—C6116.9 (3)O3—C16—C17108.3 (2)
C4—C5—C8121.1 (3)O3—C16—H16A110.0
C6—C5—C8122.0 (3)C17—C16—H16A110.0
C7—C6—C5122.3 (3)O3—C16—H16B110.0
C7—C6—H6118.9C17—C16—H16B110.0
C5—C6—H6118.9H16A—C16—H16B108.4
C6—C7—C2119.0 (3)C16—C17—H17A109.5
C6—C7—H7120.5C16—C17—H17B109.5
C2—C7—H7120.5H17A—C17—H17B109.5
N1—C8—C5121.5 (3)C16—C17—H17C109.5
N1—C8—H8119.2H17A—C17—H17C109.5
C5—C8—H8119.2H17B—C17—H17C109.5
C14—C9—C10117.3 (3)C8—N1—C9122.1 (2)
C14—C9—N1127.8 (3)C4—O1—H1109.5
C10—C9—N1114.9 (3)C2—O2—C1118.0 (2)
C11—C10—C9120.8 (3)
O2—C2—C3—C4179.0 (2)C9—C10—C11—C12−0.1 (4)
C7—C2—C3—C40.0 (3)C10—C11—C12—O3−179.1 (2)
C2—C3—C4—O1178.26 (19)C10—C11—C12—C131.8 (4)
C2—C3—C4—C5−1.2 (3)O3—C12—C13—C14178.9 (2)
O1—C4—C5—C6−178.2 (2)C11—C12—C13—C14−2.0 (4)
C3—C4—C5—C61.2 (3)C12—C13—C14—C90.6 (4)
O1—C4—C5—C81.9 (3)C10—C9—C14—C131.1 (3)
C3—C4—C5—C8−178.6 (2)N1—C9—C14—C13−179.7 (2)
C4—C5—C6—C70.0 (3)C13—C12—O3—C160.7 (3)
C8—C5—C6—C7179.8 (2)C11—C12—O3—C16−178.4 (2)
C5—C6—C7—C2−1.2 (4)C12—O3—C16—C17179.9 (2)
O2—C2—C7—C6−178.0 (2)C5—C8—N1—C9179.3 (2)
C3—C2—C7—C61.2 (3)C14—C9—N1—C88.9 (3)
C4—C5—C8—N1−4.0 (3)C10—C9—N1—C8−171.8 (2)
C6—C5—C8—N1176.2 (2)C3—C2—O2—C14.8 (3)
C14—C9—C10—C11−1.3 (3)C7—C2—O2—C1−176.0 (2)
N1—C9—C10—C11179.3 (2)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O1—H1···N10.821.832.563 (3)148
C1—H1A···Cg2i0.963.324.000 (3)129
C3—H3···Cg2i0.933.304.155 (3)155
C8—H8···Cg2ii0.933.394.269 (3)159
C10—H10···Cg1i0.933.003.849 (3)153
C16—H16B···Cg1ii0.973.043.822 (3)139

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

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BH2250).

References

  • Farrugia, L. J. (1997). J. Appl. Cryst.30, 565.
  • Farrugia, L. J. (1999). J. Appl. Cryst.32, 837–838.
  • Hadjoudis, E., Vittorakis, M. & Moustakali-Mavridis, I. (1987). Tetrahedron, 43, 1345–1360.
  • Karia, F. D. & Parsania, P. H. (1999). Asian J. Chem.11, 991–995.
  • Şahin, O., Albayrak, C., Odabaşoğlu, M. & Büyükgüngör, O. (2005). Acta Cryst. E61, o2859–o2861.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Stoe & Cie (2002). X-RED and X-AREA Stoe & Cie, Darmstadt, Germany.
  • Taggi, A. E., Hafez, A. M., Wack, H., Young, B., Ferraris, D. & Lectka, T. (2002). J. Am. Chem. Soc.124, 6626–6635. [PubMed]

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