organic compounds
(E)-4-Methoxy-2-(p-tolyliminomethyl)phenol
aFaculty of Education, Sinop University, Sinop, Turkey, and bDepartment of Physics, Ondokuz Mayıs University, TR-55139 Samsun, Turkey
*Correspondence e-mail: orhanb@omu.edu.tr
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 et al. (1980). For related structures, see: Koşar et al. (2009); Tanak & Yavuz (2010).
see: Moustakali-MavridisExperimental
Crystal data
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Refinement
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Data collection: X-AREA (Stoe & Cie, 2002); cell 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).
Supporting information
https://doi.org/10.1107/S1600536810003028/is2517sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810003028/is2517Isup2.hkl
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).
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.
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
It has been claimed that the molecules showing thermochromism are planar and showing are non-planar (Moustakali-Mavridis et al., 1980). In general, o-hydroxy 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 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 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.
is stabilized by one weak C—H···For background to thermochromic
see: Moustakali-Mavridis et al. (1980). For related structures, see: Koşar et al. (2009); Tanak & Yavuz (2010).Data collection: X-AREA (Stoe & Cie, 2002); cell
X-AREA (Stoe & Cie, 2002); 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).C15H15NO2 | F(000) = 512 |
Mr = 241.28 | Dx = 1.291 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 16465 reflections |
a = 21.1680 (9) Å | θ = 1.7–27.3° |
b = 4.7844 (2) Å | µ = 0.09 mm−1 |
c = 12.2759 (4) Å | T = 296 K |
β = 92.859 (3)° | Prism, brown |
V = 1241.71 (8) Å3 | 0.76 × 0.52 × 0.19 mm |
Z = 4 |
Stoe IPDS 2 diffractometer | 2627 independent reflections |
Radiation source: fine-focus sealed tube | 2223 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.029 |
Detector resolution: 6.67 pixels mm-1 | θmax = 26.8°, θmin = 1.9° |
ω scans | h = −26→26 |
Absorption correction: integration (X-RED32; Stoe & Cie, 2002) | k = −6→6 |
Tmin = 0.947, Tmax = 0.984 | l = −15→15 |
16465 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.043 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.127 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.08 | w = 1/[σ2(Fo2) + (0.0679P)2 + 0.1706P] where P = (Fo2 + 2Fc2)/3 |
2627 reflections | (Δ/σ)max < 0.001 |
169 parameters | Δρmax = 0.18 e Å−3 |
0 restraints | Δρmin = −0.17 e Å−3 |
C15H15NO2 | V = 1241.71 (8) Å3 |
Mr = 241.28 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 21.1680 (9) Å | µ = 0.09 mm−1 |
b = 4.7844 (2) Å | T = 296 K |
c = 12.2759 (4) Å | 0.76 × 0.52 × 0.19 mm |
β = 92.859 (3)° |
Stoe IPDS 2 diffractometer | 2627 independent reflections |
Absorption correction: integration (X-RED32; Stoe & Cie, 2002) | 2223 reflections with I > 2σ(I) |
Tmin = 0.947, Tmax = 0.984 | Rint = 0.029 |
16465 measured reflections |
R[F2 > 2σ(F2)] = 0.043 | 0 restraints |
wR(F2) = 0.127 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.08 | Δρmax = 0.18 e Å−3 |
2627 reflections | Δρmin = −0.17 e Å−3 |
169 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.30136 (5) | 0.2222 (2) | 0.54620 (9) | 0.0391 (3) | |
C2 | 0.30433 (6) | 0.1581 (3) | 0.43466 (9) | 0.0450 (3) | |
C3 | 0.34823 (7) | −0.0358 (3) | 0.40249 (10) | 0.0548 (4) | |
H3 | 0.3503 | −0.0789 | 0.3289 | 0.066* | |
C4 | 0.38887 (6) | −0.1658 (3) | 0.47753 (11) | 0.0512 (3) | |
H4 | 0.4183 | −0.2941 | 0.4543 | 0.061* | |
C5 | 0.38594 (6) | −0.1055 (3) | 0.58806 (10) | 0.0454 (3) | |
C6 | 0.34203 (6) | 0.0854 (3) | 0.62107 (10) | 0.0442 (3) | |
H6 | 0.3395 | 0.1235 | 0.6950 | 0.053* | |
C7 | 0.47395 (8) | −0.3961 (4) | 0.63806 (15) | 0.0720 (5) | |
H7A | 0.4571 | −0.5564 | 0.5996 | 0.108* | |
H7B | 0.4985 | −0.4560 | 0.7017 | 0.108* | |
H7C | 0.5004 | −0.2923 | 0.5913 | 0.108* | |
C8 | 0.25662 (5) | 0.4249 (3) | 0.58486 (9) | 0.0420 (3) | |
H8 | 0.2549 | 0.4552 | 0.6595 | 0.050* | |
C9 | 0.17663 (5) | 0.7627 (2) | 0.55871 (9) | 0.0400 (3) | |
C10 | 0.17533 (6) | 0.8537 (3) | 0.66634 (10) | 0.0491 (3) | |
H10 | 0.2043 | 0.7827 | 0.7187 | 0.059* | |
C11 | 0.13125 (6) | 1.0488 (3) | 0.69553 (11) | 0.0503 (3) | |
H11 | 0.1312 | 1.1069 | 0.7678 | 0.060* | |
C12 | 0.08726 (6) | 1.1606 (3) | 0.62089 (11) | 0.0450 (3) | |
C13 | 0.08968 (6) | 1.0724 (3) | 0.51344 (11) | 0.0518 (3) | |
H13 | 0.0610 | 1.1455 | 0.4610 | 0.062* | |
C14 | 0.13368 (6) | 0.8786 (3) | 0.48282 (10) | 0.0488 (3) | |
H14 | 0.1345 | 0.8250 | 0.4101 | 0.059* | |
C15 | 0.03942 (7) | 1.3726 (3) | 0.65439 (13) | 0.0572 (4) | |
H15A | 0.0372 | 1.3706 | 0.7323 | 0.086* | |
H15B | −0.0013 | 1.3271 | 0.6211 | 0.086* | |
H15C | 0.0519 | 1.5551 | 0.6311 | 0.086* | |
N1 | 0.21955 (5) | 0.5626 (2) | 0.51970 (8) | 0.0419 (3) | |
O1 | 0.26517 (5) | 0.2806 (3) | 0.35863 (7) | 0.0651 (3) | |
O2 | 0.42372 (5) | −0.2245 (2) | 0.66971 (8) | 0.0639 (3) | |
H1 | 0.2419 (10) | 0.410 (5) | 0.3970 (18) | 0.103 (7)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0390 (6) | 0.0401 (6) | 0.0385 (6) | −0.0012 (5) | 0.0060 (4) | −0.0015 (5) |
C2 | 0.0475 (6) | 0.0508 (7) | 0.0370 (6) | 0.0051 (5) | 0.0050 (5) | 0.0012 (5) |
C3 | 0.0614 (8) | 0.0640 (9) | 0.0398 (6) | 0.0124 (7) | 0.0105 (6) | −0.0048 (6) |
C4 | 0.0478 (7) | 0.0540 (8) | 0.0527 (7) | 0.0110 (6) | 0.0108 (6) | −0.0052 (6) |
C5 | 0.0430 (6) | 0.0469 (7) | 0.0463 (6) | 0.0032 (5) | 0.0009 (5) | 0.0010 (5) |
C6 | 0.0461 (6) | 0.0484 (7) | 0.0382 (6) | 0.0032 (5) | 0.0028 (5) | −0.0037 (5) |
C7 | 0.0635 (9) | 0.0716 (10) | 0.0799 (10) | 0.0261 (8) | −0.0057 (8) | −0.0009 (8) |
C8 | 0.0441 (6) | 0.0438 (6) | 0.0384 (6) | 0.0015 (5) | 0.0045 (5) | −0.0033 (5) |
C9 | 0.0389 (6) | 0.0384 (6) | 0.0429 (6) | −0.0010 (5) | 0.0049 (4) | −0.0010 (5) |
C10 | 0.0505 (7) | 0.0535 (7) | 0.0430 (6) | 0.0096 (6) | −0.0008 (5) | −0.0044 (5) |
C11 | 0.0550 (7) | 0.0505 (7) | 0.0458 (6) | 0.0047 (6) | 0.0063 (5) | −0.0074 (6) |
C12 | 0.0427 (6) | 0.0358 (6) | 0.0573 (7) | −0.0022 (5) | 0.0104 (5) | 0.0002 (5) |
C13 | 0.0520 (7) | 0.0495 (7) | 0.0535 (7) | 0.0096 (6) | −0.0026 (6) | 0.0037 (6) |
C14 | 0.0541 (7) | 0.0499 (7) | 0.0422 (6) | 0.0067 (6) | 0.0017 (5) | −0.0014 (5) |
C15 | 0.0541 (7) | 0.0439 (7) | 0.0748 (9) | 0.0063 (6) | 0.0152 (7) | −0.0006 (6) |
N1 | 0.0421 (5) | 0.0425 (5) | 0.0416 (5) | 0.0025 (4) | 0.0053 (4) | −0.0013 (4) |
O1 | 0.0743 (7) | 0.0839 (8) | 0.0369 (5) | 0.0305 (6) | −0.0001 (4) | −0.0002 (5) |
O2 | 0.0612 (6) | 0.0753 (7) | 0.0545 (6) | 0.0256 (5) | −0.0038 (5) | 0.0009 (5) |
C1—C6 | 1.3914 (17) | C8—H8 | 0.9300 |
C1—C2 | 1.4077 (16) | C9—C14 | 1.3846 (17) |
C1—C8 | 1.4514 (16) | C9—C10 | 1.3928 (17) |
C2—O1 | 1.3509 (15) | C9—N1 | 1.4194 (15) |
C2—C3 | 1.3843 (18) | C10—C11 | 1.3798 (18) |
C3—C4 | 1.3772 (19) | C10—H10 | 0.9300 |
C3—H3 | 0.9300 | C11—C12 | 1.3811 (18) |
C4—C5 | 1.3917 (18) | C11—H11 | 0.9300 |
C4—H4 | 0.9300 | C12—C13 | 1.3882 (19) |
C5—O2 | 1.3741 (15) | C12—C15 | 1.5050 (17) |
C5—C6 | 1.3782 (17) | C13—C14 | 1.3796 (18) |
C6—H6 | 0.9300 | C13—H13 | 0.9300 |
C7—O2 | 1.4130 (17) | C14—H14 | 0.9300 |
C7—H7A | 0.9600 | C15—H15A | 0.9600 |
C7—H7B | 0.9600 | C15—H15B | 0.9600 |
C7—H7C | 0.9600 | C15—H15C | 0.9600 |
C8—N1 | 1.2757 (15) | O1—H1 | 0.93 (2) |
C6—C1—C2 | 118.93 (11) | C14—C9—C10 | 118.01 (11) |
C6—C1—C8 | 119.39 (10) | C14—C9—N1 | 116.94 (10) |
C2—C1—C8 | 121.68 (11) | C10—C9—N1 | 125.04 (11) |
O1—C2—C3 | 119.41 (11) | C11—C10—C9 | 120.23 (12) |
O1—C2—C1 | 121.45 (11) | C11—C10—H10 | 119.9 |
C3—C2—C1 | 119.13 (11) | C9—C10—H10 | 119.9 |
C4—C3—C2 | 121.17 (12) | C10—C11—C12 | 122.14 (12) |
C4—C3—H3 | 119.4 | C10—C11—H11 | 118.9 |
C2—C3—H3 | 119.4 | C12—C11—H11 | 118.9 |
C3—C4—C5 | 120.12 (12) | C11—C12—C13 | 117.20 (11) |
C3—C4—H4 | 119.9 | C11—C12—C15 | 121.35 (12) |
C5—C4—H4 | 119.9 | C13—C12—C15 | 121.44 (12) |
O2—C5—C6 | 115.88 (11) | C14—C13—C12 | 121.37 (12) |
O2—C5—C4 | 124.94 (11) | C14—C13—H13 | 119.3 |
C6—C5—C4 | 119.18 (12) | C12—C13—H13 | 119.3 |
C5—C6—C1 | 121.45 (11) | C13—C14—C9 | 121.02 (12) |
C5—C6—H6 | 119.3 | C13—C14—H14 | 119.5 |
C1—C6—H6 | 119.3 | C9—C14—H14 | 119.5 |
O2—C7—H7A | 109.5 | C12—C15—H15A | 109.5 |
O2—C7—H7B | 109.5 | C12—C15—H15B | 109.5 |
H7A—C7—H7B | 109.5 | H15A—C15—H15B | 109.5 |
O2—C7—H7C | 109.5 | C12—C15—H15C | 109.5 |
H7A—C7—H7C | 109.5 | H15A—C15—H15C | 109.5 |
H7B—C7—H7C | 109.5 | H15B—C15—H15C | 109.5 |
N1—C8—C1 | 122.08 (11) | C8—N1—C9 | 121.40 (10) |
N1—C8—H8 | 119.0 | C2—O1—H1 | 105.0 (13) |
C1—C8—H8 | 119.0 | C5—O2—C7 | 117.30 (11) |
C6—C1—C2—O1 | 178.73 (12) | C14—C9—C10—C11 | 1.5 (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—C12 | 0.0 (2) |
C8—C1—C2—C3 | 179.61 (12) | C10—C11—C12—C13 | −1.2 (2) |
O1—C2—C3—C4 | −179.83 (13) | C10—C11—C12—C15 | 179.81 (12) |
C1—C2—C3—C4 | −0.1 (2) | C11—C12—C13—C14 | 0.8 (2) |
C2—C3—C4—C5 | 0.6 (2) | C15—C12—C13—C14 | 179.82 (12) |
C3—C4—C5—O2 | 179.39 (13) | C12—C13—C14—C9 | 0.7 (2) |
C3—C4—C5—C6 | 0.0 (2) | C10—C9—C14—C13 | −1.9 (2) |
O2—C5—C6—C1 | 179.43 (11) | N1—C9—C14—C13 | 179.26 (12) |
C4—C5—C6—C1 | −1.1 (2) | C1—C8—N1—C9 | −179.19 (10) |
C2—C1—C6—C5 | 1.62 (19) | C14—C9—N1—C8 | −173.10 (11) |
C8—C1—C6—C5 | −179.00 (11) | C10—C9—N1—C8 | 8.12 (19) |
C6—C1—C8—N1 | 177.85 (11) | C6—C5—O2—C7 | −172.88 (13) |
C2—C1—C8—N1 | −2.79 (19) | C4—C5—O2—C7 | 7.7 (2) |
Cg1 is the centroid of the C9–C14 ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···N1 | 0.93 (2) | 1.76 (2) | 2.6178 (14) | 151 (2) |
C15—H15C···Cg1i | 0.96 | 2.66 | 3.5535 (16) | 156 |
C7—H7B···O2ii | 0.96 | 2.57 | 3.496 (2) | 163 |
Symmetry codes: (i) x, y+1, z; (ii) −x+1, y−1/2, −z+3/2. |
Experimental details
Crystal data | |
Chemical formula | C15H15NO2 |
Mr | 241.28 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 296 |
a, b, c (Å) | 21.1680 (9), 4.7844 (2), 12.2759 (4) |
β (°) | 92.859 (3) |
V (Å3) | 1241.71 (8) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.76 × 0.52 × 0.19 |
Data collection | |
Diffractometer | Stoe IPDS 2 |
Absorption correction | Integration (X-RED32; Stoe & Cie, 2002) |
Tmin, Tmax | 0.947, 0.984 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 16465, 2627, 2223 |
Rint | 0.029 |
(sin θ/λ)max (Å−1) | 0.634 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.043, 0.127, 1.08 |
No. of reflections | 2627 |
No. of parameters | 169 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.18, −0.17 |
Computer programs: X-AREA (Stoe & Cie, 2002), X-RED32 (Stoe & Cie, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).
Cg1 is the centroid of the C9–C14 ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···N1 | 0.93 (2) | 1.76 (2) | 2.6178 (14) | 151 (2) |
C15—H15C···Cg1i | 0.96 | 2.655 | 3.5535 (16) | 156.1 |
C7—H7B···O2ii | 0.96 | 2.57 | 3.496 (2) | 163 |
Symmetry codes: (i) x, y+1, z; (ii) −x+1, y−1/2, −z+3/2. |
Acknowledgements
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).
References
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838. CrossRef CAS IUCr Journals Google Scholar
Koşar, B., Albayrak, Ç., Odabaşoğlu, M. & Büyükgüngör, O. (2009). Acta Cryst. C65, o517–o520. Web of Science CSD CrossRef IUCr Journals Google Scholar
Moustakali-Mavridis, I., Hadjoudis, B. & Mavridis, A. (1980). Acta Cryst. B36, 1126–1130. CSD CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Stoe & Cie (2002). X-AREA and X-RED. Stoe & Cie, Darmstadt, Germany. Google Scholar
Tanak, H. & Yavuz, M. (2010). J. Mol. Modeling, 16, 235–241. Web of Science CrossRef CAS Google Scholar
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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.