(E)-2-[2-(Hydroxy­meth­yl)phenyl­imino­meth­yl]-6-methyl­phenol

The mol­ecule of the title compound, C₁₅H₁₅NO₂, is not planar, displaying a dihedral angle of 21.21 (18)° between the two aromatic rings. The central N=C bond distance of 1.279 (4) Å is typical for an imine double bond. There are intra­molecular O—H...N and inter­molecular O—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.041
• wR factor = 0.085
• Data-to-parameter ratio = 8.9

checkCIF/PLATON results

No syntax errors found



Alert level C
GOODF01_ALERT_2_C  The least squares goodness of fit parameter lies
            outside the range 0.80 <> 2.00
            Goodness of fit given =      0.790
RINTA01_ALERT_3_C  The value of Rint is greater than 0.10
            Rint given   0.129
PLAT020_ALERT_3_C The value of Rint is greater than 0.10 .........       0.13
PLAT063_ALERT_3_C Crystal Probably too Large for Beam Size .......       0.80 mm
PLAT230_ALERT_2_C Hirshfeld Test Diff for    N1     -   C7      ..       5.45 su
PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          5

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           25.99
           From the CIF: _reflns_number_total               1460
           Count of symmetry unique reflns         1460
           Completeness (_total/calc)            100.00%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present         no

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   6 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   4 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

In this paper we present the crystal and molecular structures of a Schiff base, C₁₅H₁₅NO₂. Recently, Schiff bases have been widely investigated for their properties and applications in different fields, such as catalysis and materials chemistry (Sabater et al., 2001; Di Bella, 2001). Schiff bases derived from 2-hydroxy-1-naphthaldehyde with various alkyl or aryl N-substituents, apart from excellent donor abilities, exhibit interesting photo- and thermo-chromic features. There are two types of intramolecular hydrogen bonds in Schiff bases, which may be stabilized in keto–amine (N—H···O hydrogen bond) or phenol–imine (N···H—O hydrogen bond) tautomeric forms. The present X-ray investigation shows that the title compound exists in the phenol–imine form (Fig. 1).

The C1—N1 and C7—C8 bond lengths are 1.408 (4) and 1.442 (4) Å, respectively, and agree with the corresponding distances in (E)-2-[4-(dimethylamino)phenyliminomethyl]-6-methylphenol [1.412 (2) and 1.441 (3) Å; Gül et al., 2007]. The C7═N1 and O1—C13 bond lengths are 1.279 (4) and 1.357 (4) Å, respectively, and agree with the corresponding distances in 2-[2-(hydroxymethyl)phenyliminomethyl]phenol [1.275 (2) and 1.354 (2) Å; Ersanlı et al., 2004]. Fig.1 also shows a strong intramolecular hydrogen bond, O1—H1···N1, describing a S(6) motif. Atom O2 in the asymmetric unit acts as hydrogen–bond donor, via H2A, connecting this molecule to O2 in a symmetry related molecule at (x + 1/2, -y + 5/2, -z), forming a C(2) chain running parallel to the [100] direction (Fig. 2).

Related literature

Schiff base compounds can be classified by their photochromic and thermochromic characteristics (Cohen et al., 1964; Hadjoudis et al., 1987). Structures related to the title compound may be found in: Ersanlı et al. (2004); Gül et al. (2007). For applications of related Schiff bases, see: Sabater et al. (2001); Di Bella (2001).

S2. Experimental

The title compound was prepared by refluxing a mixture of a solution containing 3-methylsalicylaldehyde (0.1 ml, 0.82 mmol) in 20 ml e thanol and a solution containing 2-aminobenzylalcohol (0.1 g, 0.82 mmol) in 20 ml e thanol. The reaction mixture was refluxed for 1 h. Single crystals suitable for X-ray analysis were obtained by slow evaporation of an ethylalcohol solution (yield 15%; m.p. 377–379 K).

S3. Refinement

H atoms of the hydroxyl groups were refined with O—H constrained to 0.82 Å and U_iso(H) = 1.5U_eq(O). All other H atoms were placed in calculated positions and constrained to ride on their parents atoms, with C—H = 0.93–0.96 Å and U_iso(H) = 1.2U_eq(C) or 1.5U_eq(C). 986 measured Friedel pairs were merged before the final refinement cycles.

Computing details

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, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. The molecular structure of the title compound, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 40% probability level.
	Fig. 2. A packing diagram of the title compound; dashed lines indicate hydrogen bonds. Other H atoms are omitted for clarity.

(E)-2-[2-(Hydroxymethyl)phenyliminomethyl]-6-methylphenol

Crystal data

C15H15NO2	Dx = 1.281 Mg m^−3
Mr = 241.28	Melting point = 377–379 K
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 8449 reflections
a = 4.7829 (4) Å	θ = 1.9–29.1°
b = 12.7379 (13) Å	µ = 0.09 mm^−1
c = 20.532 (2) Å	T = 296 K
V = 1250.9 (2) Å^3	Prism, yellow
Z = 4	0.80 × 0.70 × 0.46 mm
F(000) = 512

Data collection

Stoe IPDSII diffractometer	1460 independent reflections
Radiation source: fine-focus sealed tube	787 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.129
Detector resolution: 6.67 pixels mm^-1	θmax = 26.0°, θmin = 1.9°
ω scans	h = −5→5
Absorption correction: integration (X-RED32; Stoe & Cie, 2002)	k = −15→15
Tmin = 0.958, Tmax = 0.994	l = −25→25
11194 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.085	H-atom parameters constrained
S = 0.79	w = 1/[σ^2(Fo^2) + (0.0356P)^2] where P = (Fo^2 + 2Fc^2)/3
1460 reflections	(Δ/σ)max < 0.001
164 parameters	Δρmax = 0.13 e Å^−3
0 restraints	Δρmin = −0.15 e Å^−3

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

	x	y	z	Uiso*/Ueq
N1	0.0147 (6)	0.98344 (19)	0.15542 (13)	0.0447 (7)
O1	−0.3647 (5)	1.11069 (18)	0.19932 (10)	0.0582 (8)
H1	−0.2500	1.0866	0.1737	0.087*
O2	0.1874 (5)	1.20510 (16)	0.01226 (10)	0.0573 (7)
H2A	0.3534	1.2131	0.0036	0.086*
C7	0.0035 (8)	0.9353 (3)	0.21002 (16)	0.0485 (9)
H7	0.1295	0.8811	0.2179	0.058*
C15	0.1614 (8)	1.1426 (2)	0.06926 (15)	0.0547 (11)
H15A	−0.0352	1.1359	0.0801	0.066*
H15B	0.2531	1.1782	0.1051	0.066*
C9	−0.2145 (9)	0.9028 (3)	0.31711 (16)	0.0616 (11)
H9	−0.0983	0.8450	0.3227	0.074*
C8	−0.1973 (7)	0.9619 (3)	0.25972 (15)	0.0436 (8)
C12	−0.5574 (8)	1.0792 (3)	0.30303 (17)	0.0509 (10)
C11	−0.5665 (9)	1.0168 (3)	0.35773 (18)	0.0632 (12)
H11	−0.6897	1.0344	0.3910	0.076*
C6	0.2859 (7)	1.0336 (2)	0.06216 (15)	0.0413 (8)
C1	0.2078 (7)	0.9556 (2)	0.10665 (15)	0.0431 (8)
C13	−0.3729 (7)	1.0500 (3)	0.25363 (16)	0.0448 (9)
C5	0.4738 (8)	1.0091 (3)	0.01373 (16)	0.0519 (9)
H5	0.5264	1.0610	−0.0157	0.062*
C4	0.5866 (8)	0.9100 (3)	0.00754 (18)	0.0568 (10)
H4	0.7146	0.8955	−0.0253	0.068*
C2	0.3168 (8)	0.8544 (3)	0.09890 (18)	0.0565 (10)
H2	0.2597	0.8010	0.1268	0.068*
C10	−0.3997 (9)	0.9290 (3)	0.36505 (17)	0.0668 (12)
H10	−0.4134	0.8880	0.4024	0.080*
C14	−0.7375 (9)	1.1733 (3)	0.29493 (19)	0.0725 (12)
H14A	−0.8577	1.1803	0.3321	0.109*
H14B	−0.8489	1.1658	0.2563	0.109*
H14C	−0.6222	1.2347	0.2911	0.109*
C3	0.5070 (9)	0.8330 (3)	0.05063 (17)	0.0609 (10)
H3	0.5825	0.7660	0.0470	0.073*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0486 (17)	0.0428 (17)	0.0428 (15)	−0.0050 (15)	0.0044 (16)	0.0048 (14)
O1	0.0690 (19)	0.0568 (15)	0.0487 (14)	0.0052 (13)	0.0006 (13)	0.0111 (12)
O2	0.0561 (16)	0.0578 (14)	0.0579 (14)	0.0031 (13)	0.0006 (15)	0.0247 (13)
C7	0.047 (2)	0.040 (2)	0.059 (2)	−0.0056 (19)	−0.002 (2)	0.0025 (17)
C15	0.067 (3)	0.051 (2)	0.046 (2)	0.005 (2)	0.002 (2)	0.0148 (17)
C9	0.082 (3)	0.051 (2)	0.052 (2)	−0.009 (2)	−0.005 (2)	0.011 (2)
C8	0.046 (2)	0.044 (2)	0.0408 (19)	−0.0072 (19)	−0.0001 (18)	0.0064 (17)
C12	0.049 (3)	0.056 (2)	0.048 (2)	−0.007 (2)	−0.002 (2)	−0.0088 (19)
C11	0.062 (3)	0.080 (3)	0.048 (2)	−0.011 (3)	0.008 (2)	−0.009 (2)
C6	0.041 (2)	0.044 (2)	0.0385 (18)	−0.0017 (18)	−0.0012 (17)	0.0007 (16)
C1	0.043 (2)	0.042 (2)	0.0440 (19)	−0.0018 (19)	−0.0028 (18)	0.0028 (16)
C13	0.045 (2)	0.050 (2)	0.0393 (18)	−0.0083 (19)	−0.0022 (18)	0.0036 (18)
C5	0.057 (2)	0.054 (2)	0.044 (2)	−0.003 (2)	0.004 (2)	0.0060 (17)
C4	0.059 (3)	0.057 (2)	0.055 (2)	0.002 (2)	0.010 (2)	−0.009 (2)
C2	0.065 (3)	0.041 (2)	0.064 (2)	−0.002 (2)	0.006 (2)	0.0025 (18)
C10	0.080 (3)	0.077 (3)	0.043 (2)	−0.020 (3)	0.004 (2)	0.014 (2)
C14	0.066 (3)	0.068 (3)	0.083 (3)	0.008 (2)	0.001 (3)	−0.016 (2)
C3	0.067 (3)	0.046 (2)	0.069 (2)	0.000 (2)	0.005 (3)	−0.007 (2)

Geometric parameters (Å, º)

N1—C7	1.279 (4)	C12—C14	1.485 (5)
N1—C1	1.408 (4)	C11—C10	1.382 (5)
O1—C13	1.357 (4)	C11—H11	0.9300
O1—H1	0.8200	C6—C5	1.376 (4)
O2—C15	1.421 (3)	C6—C1	1.400 (4)
O2—H2A	0.8200	C1—C2	1.399 (5)
C7—C8	1.442 (4)	C5—C4	1.378 (5)
C7—H7	0.9300	C5—H5	0.9300
C15—C6	1.517 (4)	C4—C3	1.375 (5)
C15—H15A	0.9700	C4—H4	0.9300
C15—H15B	0.9700	C2—C3	1.373 (5)
C9—C10	1.365 (5)	C2—H2	0.9300
C9—C8	1.400 (4)	C10—H10	0.9300
C9—H9	0.9300	C14—H14A	0.9600
C8—C13	1.408 (4)	C14—H14B	0.9600
C12—C11	1.377 (5)	C14—H14C	0.9600
C12—C13	1.395 (4)	C3—H3	0.9300
C7—N1—C1	122.0 (3)	C2—C1—C6	118.7 (3)
C13—O1—H1	109.5	C2—C1—N1	123.9 (3)
C15—O2—H2A	109.5	C6—C1—N1	117.4 (3)
N1—C7—C8	122.4 (3)	O1—C13—C12	117.6 (3)
N1—C7—H7	118.8	O1—C13—C8	120.7 (3)
C8—C7—H7	118.8	C12—C13—C8	121.7 (3)
O2—C15—C6	113.5 (3)	C6—C5—C4	122.0 (3)
O2—C15—H15A	108.9	C6—C5—H5	119.0
C6—C15—H15A	108.9	C4—C5—H5	119.0
O2—C15—H15B	108.9	C3—C4—C5	119.1 (4)
C6—C15—H15B	108.9	C3—C4—H4	120.5
H15A—C15—H15B	107.7	C5—C4—H4	120.5
C10—C9—C8	120.9 (4)	C3—C2—C1	120.8 (3)
C10—C9—H9	119.5	C3—C2—H2	119.6
C8—C9—H9	119.5	C1—C2—H2	119.6
C9—C8—C13	117.9 (3)	C9—C10—C11	119.6 (4)
C9—C8—C7	120.6 (3)	C9—C10—H10	120.2
C13—C8—C7	121.5 (3)	C11—C10—H10	120.2
C11—C12—C13	117.3 (4)	C12—C14—H14A	109.5
C11—C12—C14	122.6 (4)	C12—C14—H14B	109.5
C13—C12—C14	120.0 (3)	H14A—C14—H14B	109.5
C12—C11—C10	122.5 (4)	C12—C14—H14C	109.5
C12—C11—H11	118.7	H14A—C14—H14C	109.5
C10—C11—H11	118.7	H14B—C14—H14C	109.5
C5—C6—C1	119.0 (3)	C2—C3—C4	120.4 (4)
C5—C6—C15	122.2 (3)	C2—C3—H3	119.8
C1—C6—C15	118.8 (3)	C4—C3—H3	119.8
C1—N1—C7—C8	−178.7 (3)	C14—C12—C13—O1	0.4 (5)
C10—C9—C8—C13	1.2 (5)	C11—C12—C13—C8	−1.5 (5)
C10—C9—C8—C7	178.5 (3)	C14—C12—C13—C8	179.5 (3)
N1—C7—C8—C9	175.9 (3)	C9—C8—C13—O1	179.6 (3)
N1—C7—C8—C13	−7.0 (5)	C7—C8—C13—O1	2.3 (4)
C13—C12—C11—C10	0.7 (6)	C9—C8—C13—C12	0.6 (5)
C14—C12—C11—C10	179.7 (4)	C7—C8—C13—C12	−176.7 (3)
O2—C15—C6—C5	17.9 (5)	C1—C6—C5—C4	0.3 (5)
O2—C15—C6—C1	−162.4 (3)	C15—C6—C5—C4	179.9 (3)
C5—C6—C1—C2	−2.1 (5)	C6—C5—C4—C3	0.6 (6)
C15—C6—C1—C2	178.2 (3)	C6—C1—C2—C3	3.1 (5)
C5—C6—C1—N1	−179.9 (3)	N1—C1—C2—C3	−179.3 (3)
C15—C6—C1—N1	0.5 (4)	C8—C9—C10—C11	−2.0 (6)
C7—N1—C1—C2	27.9 (5)	C12—C11—C10—C9	1.0 (6)
C7—N1—C1—C6	−154.5 (3)	C1—C2—C3—C4	−2.2 (6)
C11—C12—C13—O1	179.4 (3)	C5—C4—C3—C2	0.3 (6)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N1	0.82	1.86	2.595 (4)	148
O2—H2A···O2^i	0.82	1.93	2.6983 (18)	155

Symmetry code: (i) x+1/2, −y+5/2, −z.