(E)-2-[3-(Trifluoro­meth­yl)phenyl­imino­meth­yl]benzene-1,4-diol

Zarife Sibel Şahin; Sümeyye Gümüş; Mustafa Macit; Şamil Işık

doi:10.1107/S1600536809041610

. 2009 Oct 17;65(Pt 11):o2754. doi: 10.1107/S1600536809041610

(E)-2-[3-(Trifluoromethyl)phenyliminomethyl]benzene-1,4-diol

Zarife Sibel Şahin ^a,^*, Sümeyye Gümüş ^b, Mustafa Macit ^b, Şamil Işık ^a

PMCID: PMC2971128 PMID: 21578348

Abstract

In the title compound, C₁₄H₁₀F₃NO₂, the two benzene rings are oriented at a dihedral angle of 31.94 (14)°. An intramolecular O—H⋯N hydrogen bond helps to stabilize the molecular structure. In the crystal, intermolecular O—H⋯O hydrogen bonding links the molecules, forming chains running along the crystallographic a axis. The F atoms of the trifluoromethyl group are disordered over two positions with refined site occupancies of 0.488 (5) and 0.512 (5).

Related literature

For the biological properties of Schiff bases, see: Lozier et al. (1975 ▶). For Schiff base tautomerism, see: Şahin et al. (2005 ▶); Hadjoudis et al. (1987 ▶). For the structure of a similar compound, see: Temel et al. (2007 ▶). For classification of hydrogen-bonding patterns, see: Bernstein et al. (1995 ▶). For related structural studies of Schiff bases, see: (Gül et al., 2007 ▶; Şahin et al., 2009a ▶,b ▶,c ▶).

Experimental

Crystal data

C₁₄H₁₀F₃NO₂
M _r = 281.23
Triclinic,
a = 7.1019 (8) Å
b = 8.5910 (8) Å
c = 11.0412 (11) Å
α = 73.862 (8)°
β = 74.133 (7)°
γ = 87.431 (8)°
V = 622.10 (11) Å³
Z = 2
Mo Kα radiation
μ = 0.13 mm⁻¹
T = 296 K
0.49 × 0.32 × 0.02 mm

Data collection

Stoe IPDS II diffractometer
Absorption correction: multi-scan (X-RED32; Stoe & Cie, 2002 ▶) T _min = 0.934, T _max = 0.995
6675 measured reflections
2548 independent reflections
1490 reflections with I > 2σ(I)
R _int = 0.073

Refinement

R[F ² > 2σ(F ²)] = 0.100
wR(F ²) = 0.293
S = 1.07
2548 reflections
183 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.62 e Å⁻³
Δρ_min = −0.56 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 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809041610/xu2631sup1.cif

e-65-o2754-sup1.cif^{(18KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809041610/xu2631Isup2.hkl

e-65-o2754-Isup2.hkl^{(122.6KB, 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
O2—H2⋯O1ⁱ	0.82	2.07	2.735 (5)	138
O1—H1⋯N1	0.91 (7)	1.74 (7)	2.569 (5)	151 (6)

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Symmetry code: (i) Inline graphic .

Acknowledgments

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

supplementary crystallographic information

Comment

The present work is part of a structral study of Schiff bases (Gül et al., 2007; Şahin et al., 2009a,b,c) and we report here the structure of (E)-2-[(3- (trifluoromethyl) phenylimino)methyl]-4-hydroxyphenol,(I). The molecular structure of (I) is shown in Figure 1.

Schiff bases often exhibit various biological activities and in many cases were shown to have antibacterial, anticancer, anti-inflammatory and antitoxic properties (Lozier et al., 1975). There are two types of intramolecular hydrogen bonds in Schiff bases, which may be stabilized either in keto-amine (N—H···O hydrogen bond) (Şahin et al., 2005) or phenol-imine (N···H—O hydrogen bond) tautomeric forms (Hadjoudis et al., 1987). The H1 atom in title compound (I) is located on O1 atom, thus the phenol-imine tautomer is favored over the keto-amine form, as indicated by the C5—O1 [1.365 (5) Å], C7—N1 [1.281 (6) Å], C6—C7 [1.448 (6) Å], C5—C6 [1.399 (6) Å] bond lengths. The O1···N1 distance of 2.569 (5)Å is comparable to those observed for analogous hydrogen bond in (E)-3-[2-(Trifluoromethyl)phenyliminomethyl]- benzene-1,2-diol [2.568 (3) Å; Temel et al., 2007]. The N1—C7 [1.281 (6) Å] bond length is consistent with significant double-bond character of these bonds. It is known that Schiff bases may exhibit thermochromism or photochromism, depending on the planarity or non-planarity of the molecule, respectively. Therefore, one can expect photochromic properties in (I) caused by non-planarity of the molecules; the dihedral angle the aromatic rings 31.94 (14)°. Molecules are linked into sheets by a combination of O—H···O hydrogen bonds (Table 1). Atom O2 in the asymmetric unit acts as hydrogen-bond donor, via H2, connecting this molecule to O1 in a symmetry related molecule at (1 + x,y,z), forming a C(7) chain running parallel to the [100] direction (Fig. 2).

Experimental

The compound (E)-2-[(3-(trifluoromethyl)phenylimino)methyl]-4-hydroxyphenol was prepared by reflux a mixture of a solution containing 2,5-dihydroxybenzaldehyde (0.0184 g, 0.13 mmol) in 20 ml ethanol and a solution containing 3- trifluoromethylaniline (0.0214 g, 0.13 mmol) in 20 ml ethanol. The reaction mixture was stirred for 1 h under reflux. The crystals of (E)-2-[(3-(trifluoromethyl)phenylimino)methyl]-4-hydroxyphenol suitable for X-ray analysis were obtained from ethylalcohol by slow evaporation (yield % 76; m.p. 404–407 K).