2-[(E)-2-Hy­droxy-5-(trifluoro­meth­oxy)benzyl­idene­amino]-4-methyl­phenol

Aslı Tosyalı Karadağ; Şehriman Atalay; Hasan Genç

doi:10.1107/S1600536810050579

. 2010 Dec 11;67(Pt 1):o95. doi: 10.1107/S1600536810050579

2-[(E)-2-Hydroxy-5-(trifluoromethoxy)benzylideneamino]-4-methylphenol

Aslı Tosyalı Karadağ ^a,^*, Şehriman Atalay ^a, Hasan Genç ^b

PMCID: PMC3050197 PMID: 21522804

Abstract

The title compound, C₁₅H₁₂F₃NO₃, is a Schiff base which adopts the cis-quinoid form in the solid state. The dihedral angle between the least-squares planes of the benzene rings being 3.6 (1)°. The F atoms of the –CF₃ group are disordered over two sets of sites with refined occupancies of 0.61 (5) and 0.39 (5). An intramolecular N—H⋯O hydrogen bond occurs. The crystal structure is stabilized by intermolecular O—H⋯O hydrogen bonds.

Related literature

Schiff base compounds can be classified by their photochromic and thermochromic characteristics, see: Calligaris et al. (1972 ▶); Cohen et al. (1964 ▶); Hadjoudis et al. (1987 ▶). For Schiff base tautomerism, see: Karabıyık et al. (2008 ▶).

Experimental

Crystal data

C₁₅H₁₂F₃NO₃
M _r = 311.26
Triclinic,
a = 6.4730 (5) Å
b = 8.4435 (6) Å
c = 13.0369 (9) Å
α = 82.171 (6)°
β = 88.034 (6)°
γ = 85.622 (6)°
V = 703.62 (9) Å³
Z = 2
Mo Kα radiation
μ = 0.13 mm⁻¹
T = 293 K
0.58 × 0.27 × 0.03 mm

Data collection

Stoe IPDS 2 diffractometer
Absorption correction: integration (X-RED32; Stoe & Cie, 2002 ▶) T _min = 0.953, T _max = 0.995
11152 measured reflections
2762 independent reflections
1328 reflections with I > 2σ(I)
R _int = 0.078

Refinement

R[F ² > 2σ(F ²)] = 0.048
wR(F ²) = 0.077
S = 0.89
2762 reflections
236 parameters
3 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.10 e Å⁻³
Δρ_min = −0.14 e Å⁻³

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, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810050579/zq2072sup1.cif

e-67-00o95-sup1.cif^{(18.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810050579/zq2072Isup2.hkl

e-67-00o95-Isup2.hkl^{(132.8KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H111⋯O2	0.99 (3)	1.72 (3)	2.546 (2)	138 (2)
O1—H1A⋯O2ⁱ	0.99 (3)	1.63 (3)	2.591 (2)	164 (3)

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors wish to acknowledge the Faculty of Arts and Sciences of Ondokuz Mayıs University, Turkey, for the use of the Stoe IPDS 2 diffractometer (purchased under grant No. F279 of the University Research Grant of Ondokuz Mayıs University).

supplementary crystallographic information

Comment

Schiff bases have been extensively used as ligands in the field of coordination chemistry (Calligaris et al., 1972). Schiff base compounds can be classified by their photochromic and thermochromic characteristics (Cohen et al., 1964). These properties result from proton transfer from the hydroxyl O atom to the imine N atom (Hadjoudis et al., 1987).

There are two types of intramolecular hydrogen bonds in Schiff bases, N—H···O hydrogen bond in keto-amine or N···H—O hydrogen bond in phenol-imine tautomeric forms (Karabıyık et al., 2008).

The present X-ray investigation shows that the title compound is a Schiff base which exists in the cis-quinoid form in the solid-state. A PLATON plot of the molecule is shown in Fig.1. The molecule is nearly planar, the angle between the least-squares planes of the benzene rings being 3.6 (1)°. The F atoms of the CF₃ group are disordered over two sets of sites with refined occupancies of 0.61 (5) and 0.39 (5). The N1—C14 bond length of 1.305 (3) Å is typical of a double bond. The crystal structure is stabilized by intra- and intermolecular O—H···O and N—H···O hydrogen bonds.

Experimental

The title compound was prepared by the reaction of a solution containing 2-hydroxy-5-(trifluoromethoxy)benzaldehyde (0.045 g 0.23 mmol) in 20 ml ethanol and a solution containing 4-amino-4-methylphenol (0.029 g 0.23 mmol) in 20 ml ethanol. The reaction mixture was stirred for 1 h under reflux. Crystals of the title compound suitable for a X-ray analysis were obtained from ethylalcohol by slow evaporation (yield 64%; m.p.402–408 K).