Crystal structure of (E)-5-benz­yloxy-2-{[(4-nitro­phen­yl)imino]­meth­yl}phenol

Nadir Ghichi; Mohamed Amine Benaouida; Ali Benboudiaf; Hocine Merazig

doi:10.1107/S2056989015022173

. 2015 Nov 28;71(Pt 12):o1000–o1001. doi: 10.1107/S2056989015022173

Crystal structure of (E)-5-benzyloxy-2-{[(4-nitrophenyl)imino]methyl}phenol

Nadir Ghichi ^a,^*, Mohamed Amine Benaouida ^a, Ali Benboudiaf ^a, Hocine Merazig ^a

PMCID: PMC4719944 PMID: 26870463

Abstract

In the title compound, C₂₀H₁₆N₂O₄, the molecule adopts an E conformation about the N=C bond. There is an intramolecular O—H⋯N hydrogen bond forming an S(6) ring motif. The nitrobenzene and benzyloxy rings are inclined to the central benzene ring by 4.34 (10) and 27.66 (11)°, respectively, and to one another by 31.40 (12)°. In the crystal, molecules are linked via C—H⋯O hydrogen bonds, forming zigzag chains along [001]. Within the chains there are C—H⋯π interactions present. The chains are linked via π–π interactions [inter-centroid distance = 3.7048 (15) Å], forming slabs parallel to the bc plane.

Keywords: crystal structure, enol, imine, Schiff base, hydrogen bonding

Related literature

For the use of Schiff bases in synthesis, see: Arora et al. (2002 ▸). For thermochromic, photochromic, biological and pharmacological activities of Schiff base compounds and their derivatives, see: Khandar et al. (2005 ▸); Tarafder et al. (2002 ▸); Hadjoudis et al. (1987 ▸). Schiff bases have been reported to show anticancer activity (Desai et al., 2001 ▸). For a related structure, see: Tzimopoulos et al. (2010 ▸). graphic file with name e-71-o1000-scheme1.jpg

Experimental

Crystal data

C₂₀H₁₆N₂O₄
M _r = 348.35
Monoclinic,
a = 15.3407 (5) Å
b = 9.5618 (3) Å
c = 11.7616 (4) Å
β = 100.615 (1)°
V = 1695.72 (10) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 293 K
0.03 × 0.02 × 0.01 mm

Data collection

Bruker APEXII CCD diffractometer
14260 measured reflections
3302 independent reflections
2389 reflections with I > 2σ(I)
R _int = 0.020

Refinement

R[F ² > 2σ(F ²)] = 0.049
wR(F ²) = 0.146
S = 1.04
3302 reflections
239 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.19 e Å⁻³
Δρ_min = −0.13 e Å⁻³

Data collection: APEX2 (Bruker, 2006 ▸); cell refinement: SAINT (Bruker, 2006 ▸); 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 ▸); software used to prepare material for publication: WinGX (Farrugia, 2012 ▸).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S2056989015022173/su5239sup1.cif

e-71-o1000-sup1.cif^{(20.1KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015022173/su5239Isup2.hkl

e-71-o1000-Isup2.hkl^{(181.3KB, hkl)}

Click here for additional data file.^{(6.6KB, cml)}

Supporting information file. DOI: 10.1107/S2056989015022173/su5239Isup3.cml

Click here for additional data file.^{(1.1MB, tif)}

. DOI: 10.1107/S2056989015022173/su5239fig1.tif

View of the molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 50% probability level. The intramolecular hydrogen bond is shown as a dashed line (see Table 1).

Click here for additional data file.^{(1.5MB, tif)}

c . DOI: 10.1107/S2056989015022173/su5239fig2.tif

A view along the c axis of the crystal packing of the title compound, showing the hydrogen bonds as dashed lines (see Table 1).

CCDC reference: 1437973

Additional supporting information: crystallographic information; 3D view; checkCIF report

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

Cg3 is the centroid of the C15–C20 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯N1	0.82	1.87	2.599 (2)	148
C9—H9⋯O2ⁱ	0.93	2.56	3.476 (2)	168
C10—H10⋯Cg3ⁱ	0.93	2.87	3.754 (2)	159

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Symmetry code: (i) Inline graphic .

Acknowledgments

We thank all researchers of the CHEMS Research Unit for their valuable assistance and MESRS (Algeria) for financial support.

supplementary crystallographic information

S1. Commentary

Schiff bases are extremely useful in the preparation of various compounds (Arora et al., 2002), and have been shown to have photochromic and thermochromic properties (Hadjoudis et al., 1987). The importance of imine derivatives has increased due to the fact that they have been shown to have anti-cancer properties (Desai et al., 2001; Khandar et al., 2005). The presence of a nitro group in various molecules and Schiff base derivatives, especially in the p-position, has an influence on the effectiveness of bacteriostatics (Tarafder et al., 2002). The title Schiff base incorporates a nitro group in the p-position and herein we report on its synthesis and crystal structure.

The molecular structure of the title compound is show in Fig 1. The molecule adopts an E conformation about the N1═C7 bond [1.284 (2) Å]. The nitrobenzene and benzyloxy rings are inclined to the central benzene ring by 4.34 (10) and 27.66 (11) °, respectively, and to one another by 31.40 (12) °. There is an intramolecular O—H···N hydrogen bond forming an S(6) ring motif (Table 1).

In the crystal, molecules are linked via N—H···O hydrogen bonds forming zigzag chains along [001]. Within the chains there are C—H···π interactions present (Table 1 and Fig. 2). The chains are linked via slipped parallel π–π interactions forming slabs parallel to the bc plane [Cg3···Cg3ⁱ = 3.7048 (15) Å; Cg3 is the centroid of ring C15—C20; inter-planar distance = 3.600 (11) Å; slippage = 0.572 Å; symmetry code: (i) -x + 2, -y + 1, -z].

S2. Synthesis and crystallisation

A mixture of 4-nitrobenzeneamine and 4-benzyloxy-2-hydroxybenzaldehyde in ethanol or methanol was refluxed for 2 h. On completion of the reaction, the orange precipitate formed was crystallized in a mixture of tetrahydrofuran and chloroform (1:2), giving very small orange crystals after one week.

S3. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. Methine H atom H7 was freely refined. The OH and other C-bound H atoms were included in calculated positions and treated as riding atoms: O—H = 0.82 Å, C—H = 0.93-1.00 Å with U_iso(H) = 1.5U_eq(O) and 1.2U_eq(C) for other H atoms.