4-Bromo-2-[(E)-{[4-nitro-2-(trifluoro­meth­yl)phen­yl]imino}­meth­yl]phenol

Mehmet Akkurt; Alan R Kennedy; Shaaban K Mohamed; Antar A Abdelhamid; Gary J Miller

doi:10.1107/S1600536812042262

. 2012 Oct 20;68(Pt 11):o3168. doi: 10.1107/S1600536812042262

4-Bromo-2-[(E)-{[4-nitro-2-(trifluoromethyl)phenyl]imino}methyl]phenol

Mehmet Akkurt ^a,^*, Alan R Kennedy ^b, Shaaban K Mohamed ^c, Antar A Abdelhamid ^c, Gary J Miller ^d

PMCID: PMC3515262 PMID: 23284482

Abstract

Except two F atoms of the –CF₃ group, the title compound, C₁₄H₈BrF₃N₂O₃, has an almost planar conformation, the dihedral angle between the aromatic rings being 3.60 (16)°. The molecule adopts the enol–imine tautomeric form, with an intramolecular O—H⋯N hydrogen bond, which generates an S(6) ring motif. In the crystal, face-to-face π–π stacking [centroid–centroid distances = 3.669 (2) and 3.732 (2) Å] between the aromatic rings of the molecules, which lie in sheets parallel to (202), help to establish the packing.

Related literature

For the biological activity of fluorine-containing compounds, see: Blair et al. (2000 ▶); Chawla et al. (2012 ▶); Bella et al. (2004 ▶); Chandra & Kumar (2005 ▶); Yang et al. (2000 ▶). For the synthesis of a similar azomethine compound, see: Mohamed et al. (2012 ▶). For the graph-set analysis of hydrogen bonding, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₁₄H₈BrF₃N₂O₃
M _r = 389.12
Monoclinic,
a = 7.3596 (5) Å
b = 16.4625 (10) Å
c = 11.2599 (6) Å
β = 94.955 (5)°
V = 1359.12 (14) Å³
Z = 4
Mo Kα radiation
μ = 3.08 mm⁻¹
T = 123 K
0.20 × 0.18 × 0.18 mm

Data collection

Oxford Diffraction Xcalibur Eos diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2010 ▶) T _min = 0.546, T _max = 0.575
6329 measured reflections
3149 independent reflections
2165 reflections with I > 2σ(I)
R _int = 0.043

Refinement

R[F ² > 2σ(F ²)] = 0.050
wR(F ²) = 0.090
S = 1.02
3149 reflections
203 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.51 e Å⁻³
Δρ_min = −0.59 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2010 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; 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 ▶) and PLATON (Spek, 2009 ▶).

Supplementary Material

Click here for additional data file.^{(23KB, cif)}

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812042262/xu5632sup1.cif

e-68-o3168-sup1.cif^{(23KB, cif)}

Click here for additional data file.^{(154.5KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812042262/xu5632Isup2.hkl

e-68-o3168-Isup2.hkl^{(154.5KB, 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
O3—H1O⋯N1	0.84	1.88	2.623 (4)	146

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Acknowledgments

Manchester Metropolitan University, Erciyes University and the University of Strathclyde are gratefully acknowledged for supporting this study.

supplementary crystallographic information

Comment

A great number of Schiff base complexes with metals have provoked wide interest because they possess a diverse spectrum of biological and pharmaceutical activities, such as antitumor and anti-oxidative activities, as well as the inhibition of lipid peroxidation (Bella et al., 2004; Chandra & Kumar, 2005; Yang et al., 2000). Fluorine can dramatically change the properties of biologically active compounds and can influence the metabolism and distribution of drug molecules in the body (Blair et al., 2000). Recently, SAR studies revealed that the presence of a fluoro group had a marked influence on the antibacterial activity (Chawla et al., 2012). Such facts and further to our studies on synthesis of bio-active molecules we herein report the synthesis and crystal structure of a new potential bio-active fluorinated azomethine compound (I).

Fig. 1 shows the title compound (I) with the enol-imine tautomeric form, which has an intramolecular O— H···N hydrogen bond forming an S(6) motif (Bernstein et al., 1995; Table 1). The C6—O3 single bond of 1.354 (4) Å and the C7═N1 double bond of 1.293 (4) Å verify the enol-imine form. These distances and the values of the other geometric parameters are in the normal range and are comparable with those of a similar compound reported previously (Mohamed et al., 2012). The two aromatic rings (C1–C6 and C8–C13) make a dihedral angle of 3.60 (16)° with each other. The C1—C7—N1—C8, O1—N2—C11—C10, O2—N2—C11—C10, C14–C9—C8—N1, C8—N1—C7—C1, C7—C1—C6—O3 and C1—C2—C3—Br1 torsion angles are 178.1 (3), 2.4 (4), 175.8 (3), -1.4 (5), -178.1 (3), 0.0 (6) and 179.2 (3) °, respectively. Therefore, the whole molecule of (I), except the F1 and F3 atoms of the –CF₃ group, is almostly planar.

The crystal structure is stabilized by face-to-face π-π stacking interactions [Cg1···Cg2(1 - x, -y, 2 - z) = 3.669 (2) Å and Cg1···Cg2(2 - x, -y, 2 - z) = 3.732 (2) Å] between the Cg1 and Cg2 centroids of the C1–C6 and C8–C13 aromatic rings of the molecules to form two-dimensional sheets parallel to the (202) plane (Fig. 2 & Fig. 3).

Experimental

The title compound was unexpectedly obtained from a three component reaction of 0.01 mol 4-nitro-2-(trifluoromethyl)aniline, 0.01 mol 5-bromosalicyaldehyde and 0.01 mol 5-phenyl-1,3-cyclohexanedione in 50 ml ethanol. The reaction mixture was refluxed for 7 h at 350 K. The solid product that obtained on cooling was filtered off, washed with cold ethanol and dried. The crude product was recrystallized from a mixture of ethanol and acetone (10:1 vv) to afford a good quality crystals suitable for X-ray difraction after two days of slow evaporation at room temperature. [Yield 83%; Mp. 511 K].