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Acta Crystallogr Sect E Struct Rep Online. 2010 February 1; 66(Pt 2): o469.
Published online 2010 January 30. doi:  10.1107/S1600536810003028
PMCID: PMC2979976

(E)-4-Meth­oxy-2-(p-tolyl­imino­meth­yl)phenol

Abstract

The mol­ecule of the title compound, C15H15NO2, adopts the enol–imine tautomeric form and has a strong intra­molecular O—H(...)N hydrogen bond as a result. The mol­ecule is almost planar, with a maximum deviation of 0.1038 (15) Å for the meth­oxy C atom. A weak C—H(...)π inter­action and a weak C—H(...)O hydrogen bond are present in the crystal.

Related literature

For background to thermochromic Schiff bases, see: Moustakali-Mavridis et al. (1980 [triangle]). For related structures, see: Koşar et al. (2009 [triangle]); Tanak & Yavuz (2010 [triangle]).

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Object name is e-66-0o469-scheme1.jpg

Experimental

Crystal data

  • C15H15NO2
  • M r = 241.28
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-0o469-efi3.jpg
  • a = 21.1680 (9) Å
  • b = 4.7844 (2) Å
  • c = 12.2759 (4) Å
  • β = 92.859 (3)°
  • V = 1241.71 (8) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.09 mm−1
  • T = 296 K
  • 0.76 × 0.52 × 0.19 mm

Data collection

  • Stoe IPDS 2 diffractometer
  • Absorption correction: integration (X-RED32; Stoe & Cie, 2002 [triangle]) T min = 0.947, T max = 0.984
  • 16465 measured reflections
  • 2627 independent reflections
  • 2223 reflections with I > 2σ(I)
  • R int = 0.029

Refinement

  • R[F 2 > 2σ(F 2)] = 0.043
  • wR(F 2) = 0.127
  • S = 1.08
  • 2627 reflections
  • 169 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.18 e Å−3
  • Δρmin = −0.17 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/S1600536810003028/is2517sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810003028/is2517Isup2.hkl

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

Acknowledgments

The authors acknowledge the Faculty of Arts and Sciences, Ondokuz Mayıs University, Turkey, for the use of the Stoe IPDS 2 diffractometer (purchased under grant F.279 of the University Research Fund).

supplementary crystallographic information

Comment

Schiff bases are formed by reaction of a primary amine and an aldehyde and have a wide area of usage as ligands in coordination chemistry. Especially o-hydroxy Schiff base derivatives are important classes and have attracted the interest of chemists and physicist because of their photochromic and thermochromic features in the solid state. These features are caused by the proton transfer to N atom from O atom with light in photochromic or with temperature in thermochromic Schiff bases. It has been claimed that the molecules showing thermochromism are planar and showing photochromism are non-planar (Moustakali-Mavridis et al., 1980). In general, o-hydroxy Schiff bases can be found at two possible tautomeric forms called as phenol-imine and keto-amine. Depending on these tautomers, two different types of intramolecular hydrogen bonding are visible in o-hydroxy Schiff bases: O—H···N in phenol-imine and N—H···O in keto-amine tautomers.

The molecular structure of the title compound is almost planar with maximum deviation of 0.1038 (15) Å for methyl C7 and exhibits an enol-imine tautomeric form, as indicated by the following bond lengths: C8═N1 [1.2757 (15) Å], C1—C8 [1.4514 (16) Å] and C2—O1 [1.3509 (15) Å]. These bond lengths are in a good agreement with observed for (E)-2-[(4-chlorophenyl)iminomethyl]-5-methoxyphenol [1.282 (2), 1.436 (2) and 1.3452 (18) Å; Koşar et al., 2009], which is also an enol-imine tautomer. The same bond lengths are comparable with observed for (E)-2-[(2-hydroxy-5-nitrophenyl)-iminomethyl]-4-nitrophenolate (1.288, 1.420 and 1.2749 Å; Tanak & Yavuz, 2010), which is a keto-amine tautomer.

As a result of enol-imine form of the molecule, there is a strong intramolecular hydrogen bond between O1 and N1 (Fig. 1). The three dimensional crystal structure is stabilized by one weak C—H···π interaction (Cg1 is the centroid of the C9–C14 ring) and one weak C—H···O hydrogen bond (between C7 and O2 of neighbor molecule) and van der Waals interactions (Figs. 2 & 3). Both intramolecular and intermolecular hydrogen bonding geometries can be seen in Table 1.

Experimental

The compound (E)-4-methoxy-2-[(p-tolylimino)methyl]phenol was prepared by reflux a mixture of a solution containing 5-methoxysalicylaldehyde (0.5 g, 3.3 mmol) in 20 ml ethanol and a solution containing 4-methylaniline (0.35 g, 3.3 mmol) in 20 ml ethanol. The reaction mixture was stirred for 1 h under reflux. The crystals of (E)-4-methoxy-2-[(p-tolylimino)methyl]phenol suitable for X-ray analysis were obtained from benzene by slow evaporation (yield 81%; m.p. 377–378 K).

Refinement

All H atoms except for H1 were refined using a riding model, with C—H distances of 0.96 Å for the methyl group and 0.93 Å for the aromatic groups. The displacement parameters of these H atoms were fixed at 1.2Ueq of their parent carbon atom for the aromatic groups and 1.5Ueq of their parent atoms for the methyl group.

Figures

Fig. 1.
A view of the title compound, with the atom-numbering scheme. Displacement ellipsoids are drawn at 50% probability and dashed line indicates intramolecular hydrogen bond.
Fig. 2.
A partial packing diagram for crystal structure, showing the C—H···π bonds as dashed lines. [Symmetry code: (i) x, y + 1, z.]
Fig. 3.
A partial packing diagram for crystal structure, showing the C—H···O intermolecular bonds as dashed lines. [Symmetry code: (ii) -x + 1, y - 1/2, -z + 3/2.]

Crystal data

C15H15NO2F(000) = 512
Mr = 241.28Dx = 1.291 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 16465 reflections
a = 21.1680 (9) Åθ = 1.7–27.3°
b = 4.7844 (2) ŵ = 0.09 mm1
c = 12.2759 (4) ÅT = 296 K
β = 92.859 (3)°Prism, brown
V = 1241.71 (8) Å30.76 × 0.52 × 0.19 mm
Z = 4

Data collection

Stoe IPDS 2 diffractometer2627 independent reflections
Radiation source: fine-focus sealed tube2223 reflections with I > 2σ(I)
graphiteRint = 0.029
Detector resolution: 6.67 pixels mm-1θmax = 26.8°, θmin = 1.9°
ω scansh = −26→26
Absorption correction: integration (X-RED32; Stoe & Cie, 2002)k = −6→6
Tmin = 0.947, Tmax = 0.984l = −15→15
16465 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)] = 0.043Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.127H atoms treated by a mixture of independent and constrained refinement
S = 1.08w = 1/[σ2(Fo2) + (0.0679P)2 + 0.1706P] where P = (Fo2 + 2Fc2)/3
2627 reflections(Δ/σ)max < 0.001
169 parametersΔρmax = 0.18 e Å3
0 restraintsΔρmin = −0.17 e Å3

Special details

Experimental. 331 frames, detector distance = 120 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)

xyzUiso*/Ueq
C10.30136 (5)0.2222 (2)0.54620 (9)0.0391 (3)
C20.30433 (6)0.1581 (3)0.43466 (9)0.0450 (3)
C30.34823 (7)−0.0358 (3)0.40249 (10)0.0548 (4)
H30.3503−0.07890.32890.066*
C40.38887 (6)−0.1658 (3)0.47753 (11)0.0512 (3)
H40.4183−0.29410.45430.061*
C50.38594 (6)−0.1055 (3)0.58806 (10)0.0454 (3)
C60.34203 (6)0.0854 (3)0.62107 (10)0.0442 (3)
H60.33950.12350.69500.053*
C70.47395 (8)−0.3961 (4)0.63806 (15)0.0720 (5)
H7A0.4571−0.55640.59960.108*
H7B0.4985−0.45600.70170.108*
H7C0.5004−0.29230.59130.108*
C80.25662 (5)0.4249 (3)0.58486 (9)0.0420 (3)
H80.25490.45520.65950.050*
C90.17663 (5)0.7627 (2)0.55871 (9)0.0400 (3)
C100.17533 (6)0.8537 (3)0.66634 (10)0.0491 (3)
H100.20430.78270.71870.059*
C110.13125 (6)1.0488 (3)0.69553 (11)0.0503 (3)
H110.13121.10690.76780.060*
C120.08726 (6)1.1606 (3)0.62089 (11)0.0450 (3)
C130.08968 (6)1.0724 (3)0.51344 (11)0.0518 (3)
H130.06101.14550.46100.062*
C140.13368 (6)0.8786 (3)0.48282 (10)0.0488 (3)
H140.13450.82500.41010.059*
C150.03942 (7)1.3726 (3)0.65439 (13)0.0572 (4)
H15A0.03721.37060.73230.086*
H15B−0.00131.32710.62110.086*
H15C0.05191.55510.63110.086*
N10.21955 (5)0.5626 (2)0.51970 (8)0.0419 (3)
O10.26517 (5)0.2806 (3)0.35863 (7)0.0651 (3)
O20.42372 (5)−0.2245 (2)0.66971 (8)0.0639 (3)
H10.2419 (10)0.410 (5)0.3970 (18)0.103 (7)*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
C10.0390 (6)0.0401 (6)0.0385 (6)−0.0012 (5)0.0060 (4)−0.0015 (5)
C20.0475 (6)0.0508 (7)0.0370 (6)0.0051 (5)0.0050 (5)0.0012 (5)
C30.0614 (8)0.0640 (9)0.0398 (6)0.0124 (7)0.0105 (6)−0.0048 (6)
C40.0478 (7)0.0540 (8)0.0527 (7)0.0110 (6)0.0108 (6)−0.0052 (6)
C50.0430 (6)0.0469 (7)0.0463 (6)0.0032 (5)0.0009 (5)0.0010 (5)
C60.0461 (6)0.0484 (7)0.0382 (6)0.0032 (5)0.0028 (5)−0.0037 (5)
C70.0635 (9)0.0716 (10)0.0799 (10)0.0261 (8)−0.0057 (8)−0.0009 (8)
C80.0441 (6)0.0438 (6)0.0384 (6)0.0015 (5)0.0045 (5)−0.0033 (5)
C90.0389 (6)0.0384 (6)0.0429 (6)−0.0010 (5)0.0049 (4)−0.0010 (5)
C100.0505 (7)0.0535 (7)0.0430 (6)0.0096 (6)−0.0008 (5)−0.0044 (5)
C110.0550 (7)0.0505 (7)0.0458 (6)0.0047 (6)0.0063 (5)−0.0074 (6)
C120.0427 (6)0.0358 (6)0.0573 (7)−0.0022 (5)0.0104 (5)0.0002 (5)
C130.0520 (7)0.0495 (7)0.0535 (7)0.0096 (6)−0.0026 (6)0.0037 (6)
C140.0541 (7)0.0499 (7)0.0422 (6)0.0067 (6)0.0017 (5)−0.0014 (5)
C150.0541 (7)0.0439 (7)0.0748 (9)0.0063 (6)0.0152 (7)−0.0006 (6)
N10.0421 (5)0.0425 (5)0.0416 (5)0.0025 (4)0.0053 (4)−0.0013 (4)
O10.0743 (7)0.0839 (8)0.0369 (5)0.0305 (6)−0.0001 (4)−0.0002 (5)
O20.0612 (6)0.0753 (7)0.0545 (6)0.0256 (5)−0.0038 (5)0.0009 (5)

Geometric parameters (Å, °)

C1—C61.3914 (17)C8—H80.9300
C1—C21.4077 (16)C9—C141.3846 (17)
C1—C81.4514 (16)C9—C101.3928 (17)
C2—O11.3509 (15)C9—N11.4194 (15)
C2—C31.3843 (18)C10—C111.3798 (18)
C3—C41.3772 (19)C10—H100.9300
C3—H30.9300C11—C121.3811 (18)
C4—C51.3917 (18)C11—H110.9300
C4—H40.9300C12—C131.3882 (19)
C5—O21.3741 (15)C12—C151.5050 (17)
C5—C61.3782 (17)C13—C141.3796 (18)
C6—H60.9300C13—H130.9300
C7—O21.4130 (17)C14—H140.9300
C7—H7A0.9600C15—H15A0.9600
C7—H7B0.9600C15—H15B0.9600
C7—H7C0.9600C15—H15C0.9600
C8—N11.2757 (15)O1—H10.93 (2)
C6—C1—C2118.93 (11)C14—C9—C10118.01 (11)
C6—C1—C8119.39 (10)C14—C9—N1116.94 (10)
C2—C1—C8121.68 (11)C10—C9—N1125.04 (11)
O1—C2—C3119.41 (11)C11—C10—C9120.23 (12)
O1—C2—C1121.45 (11)C11—C10—H10119.9
C3—C2—C1119.13 (11)C9—C10—H10119.9
C4—C3—C2121.17 (12)C10—C11—C12122.14 (12)
C4—C3—H3119.4C10—C11—H11118.9
C2—C3—H3119.4C12—C11—H11118.9
C3—C4—C5120.12 (12)C11—C12—C13117.20 (11)
C3—C4—H4119.9C11—C12—C15121.35 (12)
C5—C4—H4119.9C13—C12—C15121.44 (12)
O2—C5—C6115.88 (11)C14—C13—C12121.37 (12)
O2—C5—C4124.94 (11)C14—C13—H13119.3
C6—C5—C4119.18 (12)C12—C13—H13119.3
C5—C6—C1121.45 (11)C13—C14—C9121.02 (12)
C5—C6—H6119.3C13—C14—H14119.5
C1—C6—H6119.3C9—C14—H14119.5
O2—C7—H7A109.5C12—C15—H15A109.5
O2—C7—H7B109.5C12—C15—H15B109.5
H7A—C7—H7B109.5H15A—C15—H15B109.5
O2—C7—H7C109.5C12—C15—H15C109.5
H7A—C7—H7C109.5H15A—C15—H15C109.5
H7B—C7—H7C109.5H15B—C15—H15C109.5
N1—C8—C1122.08 (11)C8—N1—C9121.40 (10)
N1—C8—H8119.0C2—O1—H1105.0 (13)
C1—C8—H8119.0C5—O2—C7117.30 (11)
C6—C1—C2—O1178.73 (12)C14—C9—C10—C111.5 (2)
C8—C1—C2—O1−0.64 (19)N1—C9—C10—C11−179.72 (11)
C6—C1—C2—C3−1.02 (19)C9—C10—C11—C120.0 (2)
C8—C1—C2—C3179.61 (12)C10—C11—C12—C13−1.2 (2)
O1—C2—C3—C4−179.83 (13)C10—C11—C12—C15179.81 (12)
C1—C2—C3—C4−0.1 (2)C11—C12—C13—C140.8 (2)
C2—C3—C4—C50.6 (2)C15—C12—C13—C14179.82 (12)
C3—C4—C5—O2179.39 (13)C12—C13—C14—C90.7 (2)
C3—C4—C5—C60.0 (2)C10—C9—C14—C13−1.9 (2)
O2—C5—C6—C1179.43 (11)N1—C9—C14—C13179.26 (12)
C4—C5—C6—C1−1.1 (2)C1—C8—N1—C9−179.19 (10)
C2—C1—C6—C51.62 (19)C14—C9—N1—C8−173.10 (11)
C8—C1—C6—C5−179.00 (11)C10—C9—N1—C88.12 (19)
C6—C1—C8—N1177.85 (11)C6—C5—O2—C7−172.88 (13)
C2—C1—C8—N1−2.79 (19)C4—C5—O2—C77.7 (2)

Hydrogen-bond geometry (Å, °)

Cg1 is the centroid of the C9–C14 ring.
D—H···AD—HH···AD···AD—H···A
O1—H1···N10.93 (2)1.76 (2)2.6178 (14)151 (2)
C15—H15C···Cg1i0.962.663.5535 (16)156
C7—H7B···O2ii0.962.573.496 (2)163

Symmetry codes: (i) x, y+1, z; (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: IS2517).

References

  • Farrugia, L. J. (1997). J. Appl. Cryst.30, 565.
  • Farrugia, L. J. (1999). J. Appl. Cryst.32, 837–838.
  • Koşar, B., Albayrak, Ç., Odabaşoğlu, M. & Büyükgüngör, O. (2009). Acta Cryst. C65, o517–o520. [PubMed]
  • Moustakali-Mavridis, I., Hadjoudis, B. & Mavridis, A. (1980). Acta Cryst. B36, 1126–1130.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Stoe & Cie (2002). X-AREA and X-RED Stoe & Cie, Darmstadt, Germany.
  • Tanak, H. & Yavuz, M. (2010). J. Mol. Modeling, 16, 235–241. [PubMed]

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