Crystal structure of 4-chloro-2-{(E)-[(3,4-di­methyl­phen­yl)imino]­meth­yl}phenol

Salim, M.; Tahir, M.N.; Munawar, M.A.; Shahid, M.; Shad, H.A.

doi:10.1107/S2056989015009354

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 71| Part 6| June 2015| Page o416

doi:10.1107/S2056989015009354

Open

access

Crystal structure of 4-chloro-2-{(E)-[(3,4-dimethylphenyl)imino]methyl}phenol

Muhammad Salim,^a Muhammad Nawaz Tahir,^b ^* Munawar Ali Munawar,^a Muhammad Shahid ^a and Hazoor Ahmad Shad ^c

^aDepartment of Chemistry, University of the Punjab, Lahore, Punjab, Pakistan, ^bDepartment of Physics, University of Sargodha, Sargodha, Punjab, Pakistan, and ^cDepartment of Chemistry, University of Sargodha, Sargodha, Punjab, Pakistan
^*Correspondence e-mail: dmntahir_uos@yahoo.com

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 10 May 2015; accepted 16 May 2015; online 23 May 2015)

In the title compound, C₁₅H₁₄ClNO, which is isostructural with its bromo analogue [Tahir et al. (2012 ). Acta Cryst., E68, o2730], the dihedral angle between the planes of the aromatic rings is 2.71 (7)° and an intramolecular O—H⋯N hydrogen bond closes an S(6) ring. In the crystal, extremely weak C—H⋯π interactions link the molecules into a three-dimensional network.

Keywords: crystal structure; phenol; intramolecular hydrogen bonding; C—H⋯π interactions.

CCDC reference: 1401503

1. Related literature

For related structures, see: Demircioğlu et al. (2014 ); Jin et al. (2012 ); Sun et al. (2013 ); Tahir et al. (2012).

2. Experimental

2.1. Crystal data

C₁₅H₁₄ClNO
M_r = 259.72
Monoclinic, P 2₁ /n
a = 12.1875 (10) Å
b = 7.4438 (5) Å
c = 14.3141 (12) Å
β = 101.549 (4)°
V = 1272.30 (17) Å³
Z = 4
Mo Kα radiation
μ = 0.29 mm⁻¹
T = 296 K
0.25 × 0.20 × 0.14 mm

2.2. Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2007 ) T_min = 0.933, T_max = 0.968
10293 measured reflections
2785 independent reflections
1871 reflections with I > 2σ(I)
R_int = 0.024

2.3. Refinement

R[F² > 2σ(F²)] = 0.041
wR(F²) = 0.116
S = 1.04
2785 reflections
166 parameters
H-atom parameters constrained
Δρ_max = 0.24 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

Cg1 and Cg2 are the centroids of the C1–C6 and C8–C13 benzene rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯N1	0.82	1.87	2.5998 (19)	149
C3—H3⋯Cg1ⁱ	0.93	2.98	3.732 (2)	139
C6—H6⋯Cg2ⁱⁱ	0.93	2.93	3.576 (2)	128
C14—H14B⋯Cg2ⁱⁱⁱ	0.96	2.96	3.656 (2)	131
Symmetry codes: (i) $[-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (ii) $[x+{\script{1\over 2}}, -y+{\script{3\over 2}}, z+{\script{1\over 2}}]$ ; (iii) $[-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015 ); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ) and PLATON (Spek, 2009 ); software used to prepare material for publication: WinGX (Farrugia, 2012) and PLATON.

Supporting information

CCDC reference: 1401503

Crystal structure: contains datablocks global, I. DOI: 10.1107/S2056989015009354/hb7424sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S2056989015009354/hb7424Isup2.hkl

Supporting information file. DOI: 10.1107/S2056989015009354/hb7424Isup3.cml

checkCIF report

Comment top

The title compound, (I, Fig. 1) has been synthesized in continuation of forming different derivatives of 3,4-dimethylaniline. (I) will also be utilized for synthesizing different metal complexes.

The crystal structures of 4-bromo-2-((E)-[(3,4-dimethylphenyl)imino]methyl)phenol (Tahir et al., 2012), 2-((3,4-dimethylphenyl)carbonoimidoyl)-3-methoxyphenol (Demircioğlu et al., 2014), N-[(E)-4-bromobenzylidene]-3,4-dimethylaniline (Sun et al., 2013) and N-[(E)-4-fluorobenzylidene]-3,4-dimethylaniline (Jin et al., 2012) have been published which are related to the title compound.

The title compound is isostructural to 4-bromo-2-((E)-[(3,4-dimethyl phenyl)imino]methyl)phenol (Tahir et al., 2012) and is almost planar with r. m. s. deviation of 0.0325 Å, with maximum deviation of 0.0803 (9) Å for Cl1 atom from the mean square plane. There exist intramolecular H-bonding of O—H···N type (Table 1, Fig. 1) with S(6) ring motif. There exist C—H···π interactions (Table 1).

Related literature top

For related structures, see: Demircioğlu et al. (2014); Jin et al. (2012); Sun et al. (2013); Tahir et al. (2012).

Experimental top

Equimolar quantities of 5-chlorosalicylaldehyde and 3,4-dimethylaniline were refluxed in methanol for 3 h. The solution was kept at room temperature for crystallization which affoarded light yellow plates after 72 h.

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and PLATON (Spek, 2009); software used to prepare material for publication: WinGX (Farrugia, 2012) and PLATON (Spek, 2009).

Figures top

	Fig. 1. View of the title compound with displacement ellipsoids drawn at the 50% probability level. The dotted line shows intramolecular H-bonding.
	Fig. 2. Packing diagram for the title compound.

4-Chloro-2-{(E)-[(3,4-dimethylphenyl)imino]methyl}phenol top

Crystal data top

C₁₅H₁₄ClNO	F(000) = 544
M_r = 259.72	D_x = 1.356 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
a = 12.1875 (10) Å	Cell parameters from 1871 reflections
b = 7.4438 (5) Å	θ = 2.0–27.0°
c = 14.3141 (12) Å	µ = 0.29 mm⁻¹
β = 101.549 (4)°	T = 296 K
V = 1272.30 (17) Å³	Plate, light yellow
Z = 4	0.25 × 0.20 × 0.14 mm

Data collection top

Bruker Kappa APEXII CCD diffractometer	2785 independent reflections
Radiation source: fine-focus sealed tube	1871 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.024
Detector resolution: 7.80 pixels mm^-1	θ_max = 27.0°, θ_min = 2.0°
ω scans	h = −15→12
Absorption correction: multi-scan (SADABS; Bruker, 2007)	k = −8→9
T_min = 0.933, T_max = 0.968	l = −18→15
10293 measured reflections

Refinement top

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)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.116	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.0519P)² + 0.2053P] where P = (F_o² + 2F_c²)/3
2785 reflections	(Δ/σ)_max = 0.001
166 parameters	Δρ_max = 0.24 e Å⁻³
0 restraints	Δρ_min = −0.22 e Å⁻³

Crystal data top

C₁₅H₁₄ClNO	V = 1272.30 (17) Å³
M_r = 259.72	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 12.1875 (10) Å	µ = 0.29 mm⁻¹
b = 7.4438 (5) Å	T = 296 K
c = 14.3141 (12) Å	0.25 × 0.20 × 0.14 mm
β = 101.549 (4)°

Data collection top

Bruker Kappa APEXII CCD diffractometer	2785 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2007)	1871 reflections with I > 2σ(I)
T_min = 0.933, T_max = 0.968	R_int = 0.024
10293 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.041	0 restraints
wR(F²) = 0.116	H-atom parameters constrained
S = 1.04	Δρ_max = 0.24 e Å⁻³
2785 reflections	Δρ_min = −0.22 e Å⁻³
166 parameters

Special details top

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

	x	y	z	U_iso*/U_eq
Cl1	0.31558 (4)	0.47763 (8)	0.94032 (3)	0.0702 (2)
O1	0.45252 (11)	0.6419 (2)	0.58212 (9)	0.0684 (4)
H1	0.4036	0.6151	0.5361	0.103*
N1	0.26240 (12)	0.51118 (17)	0.49303 (10)	0.0442 (4)
C1	0.41674 (14)	0.6064 (2)	0.66249 (12)	0.0462 (4)
C2	0.31233 (14)	0.5273 (2)	0.66205 (11)	0.0400 (4)
C3	0.28167 (14)	0.4894 (2)	0.74847 (12)	0.0434 (4)
H3	0.2128	0.4363	0.7492	0.052*
C4	0.35292 (14)	0.5305 (2)	0.83271 (12)	0.0447 (4)
C5	0.45476 (15)	0.6104 (2)	0.83316 (12)	0.0499 (4)
H5	0.5022	0.6383	0.8907	0.060*
C6	0.48620 (15)	0.6486 (2)	0.74880 (13)	0.0524 (5)
H6	0.5549	0.7035	0.7493	0.063*
C7	0.23682 (15)	0.4821 (2)	0.57324 (12)	0.0432 (4)
H7	0.1679	0.4304	0.5753	0.052*
C8	0.18970 (13)	0.4694 (2)	0.40504 (11)	0.0394 (4)
C9	0.23021 (14)	0.5050 (2)	0.32363 (12)	0.0414 (4)
H9	0.3016	0.5534	0.3296	0.050*
C10	0.16807 (14)	0.4712 (2)	0.23319 (12)	0.0407 (4)
C11	0.06064 (14)	0.3993 (2)	0.22426 (12)	0.0429 (4)
C12	0.02122 (14)	0.3625 (2)	0.30650 (12)	0.0455 (4)
H12	−0.0499	0.3133	0.3010	0.055*
C13	0.08330 (14)	0.3962 (2)	0.39585 (12)	0.0456 (4)
H13	0.0544	0.3701	0.4497	0.055*
C14	0.21523 (18)	0.5150 (3)	0.14640 (13)	0.0576 (5)
H14A	0.2165	0.4083	0.1089	0.086*
H14B	0.2901	0.5603	0.1659	0.086*
H14C	0.1693	0.6042	0.1090	0.086*
C15	−0.01190 (16)	0.3653 (3)	0.12815 (13)	0.0599 (5)
H15A	0.0236	0.2788	0.0943	0.090*
H15B	−0.0225	0.4756	0.0927	0.090*
H15C	−0.0832	0.3200	0.1360	0.090*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0742 (4)	0.1002 (4)	0.0366 (3)	−0.0049 (3)	0.0120 (2)	0.0047 (2)
O1	0.0658 (9)	0.0930 (10)	0.0483 (8)	−0.0276 (8)	0.0159 (7)	0.0033 (7)
N1	0.0472 (8)	0.0498 (8)	0.0349 (8)	−0.0009 (6)	0.0069 (6)	−0.0023 (6)
C1	0.0493 (10)	0.0475 (10)	0.0428 (10)	−0.0042 (8)	0.0116 (8)	0.0025 (7)
C2	0.0427 (9)	0.0390 (9)	0.0376 (9)	0.0015 (7)	0.0061 (7)	−0.0012 (7)
C3	0.0430 (10)	0.0469 (10)	0.0407 (9)	0.0001 (7)	0.0093 (8)	−0.0005 (7)
C4	0.0493 (11)	0.0476 (10)	0.0364 (9)	0.0048 (8)	0.0065 (8)	0.0002 (7)
C5	0.0519 (11)	0.0500 (10)	0.0432 (10)	−0.0005 (8)	−0.0013 (8)	−0.0027 (8)
C6	0.0476 (11)	0.0523 (11)	0.0550 (12)	−0.0103 (8)	0.0048 (9)	−0.0008 (9)
C7	0.0440 (10)	0.0450 (9)	0.0404 (10)	−0.0016 (7)	0.0080 (8)	−0.0015 (7)
C8	0.0421 (10)	0.0383 (9)	0.0376 (9)	0.0011 (7)	0.0073 (7)	−0.0016 (7)
C9	0.0404 (9)	0.0421 (9)	0.0423 (10)	−0.0036 (7)	0.0102 (7)	−0.0015 (7)
C10	0.0480 (10)	0.0368 (9)	0.0389 (9)	0.0015 (7)	0.0125 (7)	0.0007 (7)
C11	0.0482 (10)	0.0368 (9)	0.0417 (10)	0.0013 (7)	0.0040 (7)	−0.0007 (7)
C12	0.0410 (9)	0.0474 (10)	0.0482 (10)	−0.0044 (8)	0.0091 (8)	0.0017 (8)
C13	0.0467 (10)	0.0520 (10)	0.0400 (10)	−0.0016 (8)	0.0132 (8)	0.0029 (8)
C14	0.0672 (13)	0.0661 (12)	0.0422 (10)	−0.0091 (9)	0.0171 (9)	0.0008 (8)
C15	0.0621 (12)	0.0674 (13)	0.0461 (11)	−0.0079 (10)	0.0008 (9)	−0.0017 (9)

Geometric parameters (Å, º) top

Cl1—C4	1.7365 (17)	C8—C13	1.389 (2)
O1—C1	1.336 (2)	C9—C10	1.386 (2)
O1—H1	0.8200	C9—H9	0.9300
N1—C7	1.267 (2)	C10—C11	1.396 (2)
N1—C8	1.422 (2)	C10—C14	1.505 (2)
C1—C6	1.387 (2)	C11—C12	1.385 (2)
C1—C2	1.401 (2)	C11—C15	1.500 (2)
C2—C3	1.391 (2)	C12—C13	1.372 (2)
C2—C7	1.452 (2)	C12—H12	0.9300
C3—C4	1.372 (2)	C13—H13	0.9300
C3—H3	0.9300	C14—H14A	0.9600
C4—C5	1.375 (2)	C14—H14B	0.9600
C5—C6	1.368 (2)	C14—H14C	0.9600
C5—H5	0.9300	C15—H15A	0.9600
C6—H6	0.9300	C15—H15B	0.9600
C7—H7	0.9300	C15—H15C	0.9600
C8—C9	1.379 (2)

C1—O1—H1	109.5	C8—C9—H9	118.9
C7—N1—C8	122.85 (15)	C10—C9—H9	118.9
O1—C1—C6	118.44 (15)	C9—C10—C11	118.83 (15)
O1—C1—C2	122.14 (15)	C9—C10—C14	120.27 (16)
C6—C1—C2	119.42 (15)	C11—C10—C14	120.89 (15)
C3—C2—C1	119.12 (15)	C12—C11—C10	118.45 (15)
C3—C2—C7	119.72 (15)	C12—C11—C15	120.34 (16)
C1—C2—C7	121.15 (15)	C10—C11—C15	121.20 (16)
C4—C3—C2	120.07 (16)	C13—C12—C11	122.41 (16)
C4—C3—H3	120.0	C13—C12—H12	118.8
C2—C3—H3	120.0	C11—C12—H12	118.8
C3—C4—C5	120.82 (16)	C12—C13—C8	119.34 (15)
C3—C4—Cl1	119.80 (14)	C12—C13—H13	120.3
C5—C4—Cl1	119.37 (13)	C8—C13—H13	120.3
C6—C5—C4	119.86 (16)	C10—C14—H14A	109.5
C6—C5—H5	120.1	C10—C14—H14B	109.5
C4—C5—H5	120.1	H14A—C14—H14B	109.5
C5—C6—C1	120.69 (16)	C10—C14—H14C	109.5
C5—C6—H6	119.7	H14A—C14—H14C	109.5
C1—C6—H6	119.7	H14B—C14—H14C	109.5
N1—C7—C2	121.73 (16)	C11—C15—H15A	109.5
N1—C7—H7	119.1	C11—C15—H15B	109.5
C2—C7—H7	119.1	H15A—C15—H15B	109.5
C9—C8—C13	118.75 (15)	C11—C15—H15C	109.5
C9—C8—N1	116.19 (14)	H15A—C15—H15C	109.5
C13—C8—N1	125.06 (14)	H15B—C15—H15C	109.5
C8—C9—C10	122.23 (15)

O1—C1—C2—C3	178.21 (15)	C7—N1—C8—C9	−178.57 (14)
C6—C1—C2—C3	−1.3 (2)	C7—N1—C8—C13	1.2 (3)
O1—C1—C2—C7	−0.9 (3)	C13—C8—C9—C10	0.4 (2)
C6—C1—C2—C7	179.60 (15)	N1—C8—C9—C10	−179.85 (13)
C1—C2—C3—C4	0.4 (2)	C8—C9—C10—C11	0.3 (2)
C7—C2—C3—C4	179.50 (14)	C8—C9—C10—C14	179.07 (14)
C2—C3—C4—C5	0.5 (3)	C9—C10—C11—C12	−0.8 (2)
C2—C3—C4—Cl1	−178.37 (12)	C14—C10—C11—C12	−179.62 (15)
C3—C4—C5—C6	−0.4 (3)	C9—C10—C11—C15	178.03 (15)
Cl1—C4—C5—C6	178.42 (13)	C14—C10—C11—C15	−0.7 (2)
C4—C5—C6—C1	−0.5 (3)	C10—C11—C12—C13	0.8 (3)
O1—C1—C6—C5	−178.16 (16)	C15—C11—C12—C13	−178.10 (15)
C2—C1—C6—C5	1.4 (3)	C11—C12—C13—C8	−0.1 (3)
C8—N1—C7—C2	−179.54 (13)	C9—C8—C13—C12	−0.5 (2)
C3—C2—C7—N1	−178.66 (14)	N1—C8—C13—C12	179.79 (15)
C1—C2—C7—N1	0.4 (3)

Hydrogen-bond geometry (Å, º) top

Cg1 and Cg2 are the centroids of the C1–C6 and C8–C13 benzene rings, respectively.

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N1	0.82	1.87	2.5998 (19)	149
C3—H3···Cg1ⁱ	0.93	2.98	3.732 (2)	139
C6—H6···Cg2ⁱⁱ	0.93	2.93	3.576 (2)	128
C14—H14B···Cg2ⁱⁱⁱ	0.96	2.96	3.656 (2)	131

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

Hydrogen-bond geometry (Å, º) top

Cg1 and Cg2 are the centroids of the C1–C6 and C8–C13 benzene rings, respectively.

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N1	0.82	1.87	2.5998 (19)	148.8
C3—H3···Cg1ⁱ	0.93	2.98	3.732 (2)	139
C6—H6···Cg2ⁱⁱ	0.93	2.93	3.576 (2)	128
C14—H14B···Cg2ⁱⁱⁱ	0.96	2.96	3.656 (2)	131

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

Acknowledgements

The authors acknowledge the provision of funds for the purchase of the diffractometer and encouragement by Dr Muhammad Akram Chaudhary, Vice Chancellor, University of Sargodha, Pakistan.

References

Bruker (2007). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Demircioğlu, Z., Albayrak, C., Çiğdem, & Büyükgüngör, O. (2014). J. Mol. Struct. 1065–1066, 210–222. Google Scholar
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854. Web of Science CrossRef CAS IUCr Journals Google Scholar
Jin, Y.-B., Chang, Y.-K., Zhang, Y. & Lei, K.-W. (2012). Acta Cryst. E68, o2415. CSD CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sun, L.-X., Zhu, L.-Z. & Wang, J.-K. (2013). Acta Cryst. E69, o631. CSD CrossRef IUCr Journals Google Scholar
Tahir, M. N., Khan, A. H., Tariq, M. I., Hussain, I. & Shafiq, M. (2012). Acta Cryst. E68, o2730. CSD CrossRef IUCr Journals Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 71| Part 6| June 2015| Page o416

doi:10.1107/S2056989015009354

Open

access

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Plain Text

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Plain Text

Search IUCr Journals		doi		Advanced search
Author		volume	page

organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Crystal structure of 4-chloro-2-{(E)-[(3,4-di­methyl­phen­yl)imino]­meth­yl}phenol

1. Related literature

2. Experimental

2.1. Crystal data

2.2. Data collection

2.3. Refinement

Supporting information

Acknowledgements

References

organic compounds

Crystal structure of 4-chloro-2-{(E)-[(3,4-dimethylphenyl)imino]methyl}phenol