(E)-1-[(2,4,6-Tri­bromo­phen­yl)diazen­yl]naphthalen-2-ol

Souheyla Chetioui; Issam Boudraa; Sofiane Bouacida; Abdelkader Bouchoul; Salah Eddine Bouaoud

doi:10.1107/S1600536813018977

. 2013 Jul 13;69(Pt 8):o1250. doi: 10.1107/S1600536813018977

(E)-1-[(2,4,6-Tribromophenyl)diazenyl]naphthalen-2-ol

Souheyla Chetioui ^a, Issam Boudraa ^a,^*, Sofiane Bouacida ^a, Abdelkader Bouchoul ^a, Salah Eddine Bouaoud ^a

PMCID: PMC3793751 PMID: 24109338

Abstract

The title azo molecule, C₁₆H₉Br₃N₂O, adopts a trans conformation with respect to the azo N=N double bond. An intramolecular O—H⋯N hydrogen bond forms an S(6) ring motif. The dihedral angle between the naphthalene ring system and the benzene ring is 33.80 (16)°. In the crystal, molecules are stacked in columns along the a axis by π–π interactions [centroid–centroid distances = 3.815 (3) and 3.990 (3) Å].

Related literature

For applications of azo compounds, see: Gale et al. (1998 ▶). For the synthesis of similar compounds, see: Wang et al. (2003 ▶); Heinrich et al. (2007 ▶). For bond lengths and angles in related azo compounds, see: Deveci et al. (2005 ▶); El-Ghamry et al. (2008 ▶). graphic file with name e-69-o1250-scheme1.jpg

Experimental

Crystal data

C₁₆H₉Br₃N₂O
M _r = 484.98
Orthorhombic,
a = 3.9904 (11) Å
b = 15.689 (4) Å
c = 24.580 (7) Å
V = 1538.8 (7) Å³
Z = 4
Mo Kα radiation
μ = 7.87 mm⁻¹
T = 293 K
0.03 × 0.02 × 0.02 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ▶) T _min = 0.244, T _max = 0.332
13143 measured reflections
3841 independent reflections
2910 reflections with I > 2σ(I)
R _int = 0.046

Refinement

R[F ² > 2σ(F ²)] = 0.034
wR(F ²) = 0.066
S = 0.96
3841 reflections
199 parameters
H-atom parameters constrained
Δρ_max = 0.44 e Å⁻³
Δρ_min = −0.44 e Å⁻³
Absolute structure: Flack (1983 ▶), 1553 Friedel pairs
Flack parameter: 0.004 (13)

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: SHELXL97 (Sheldrick, 2008 ▶); 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) global, I. DOI: 10.1107/S1600536813018977/is5290sup1.cif

e-69-o1250-sup1.cif^{(24.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813018977/is5290Isup2.hkl

e-69-o1250-Isup2.hkl^{(184.5KB, hkl)}

Click here for additional data file.^{(5.3KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536813018977/is5290Isup3.cml

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
O1—H1⋯N1	0.82	1.85	2.561 (4)	144

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Acknowledgments

We thank all researchers of the CHEMS Research Unit, University of Constantine, Algeria, for their valuable assistance. Thanks are due to the MESRS (Ministère de l’Enseignement Supérieur et de la Recherche Scientifique – Algérie) for financial support. We also express our gratitude to Professor L. Ouahab, Director of Research at the Laboratory UMR LCSIM 6511, CNRS, Rennes I (France), for recording the diffraction data and help with the structure determination.

supplementary crystallographic information

Comment

It has been known for many years that the azo compounds are a widely used class of dyes due to their application in various fields such as the dyeing of textile fibers, the coloring of different materials, colored plastics and electrochemical sensors (Gale et al., 1998). Azo dyes are synthetic colours that contain an azo group, as part of the structure. They are characterized by the azo linkage (–N=N–). Azo groups do not occur naturally. Many azo compounds have been synthesized by the diazotization and diazo coupling reaction (Wang et al., 2003), which entails an electrophilic substitution reaction where an aryl diazonium-cation attacks another aryl ring, since diazonium salts are often unstable near room temperature; the azo coupling reactions are typically conducted near ice temperature.

The pH of solution is quite important; it must be mildly acidic or neutral, since no reaction takes place if the pH is too low (Heinrich et al., 2007). We report herein the crystal structure of the title compound (Fig. 1), obtained through the diazotization of 2,4,6-tribromoaniline followed by a coupling reaction with 2-naphthol. In the molecule of the title compound, all bond lengths are in good agreement with those reported for other azo compounds (Deveci et al., 2005; El-Ghamry et al., 2008). The bond lengths and angles are within normal ranges. The naphthalene ring system is oriented at a dihedral angle of 33.80 (16)° with respect to the benzene ring. In the crystal, molecules are packed into columns along the a axis by π–π interactions between adjacent molecules with the closest approach between centroids of aromatic rings being 3.815 (3) Å (Fig. 2).

Experimental

The title compound was prepared by the previously reported method in the literature; following the classical method of synthesis of other aromatic azo-compounds, diazotization of 2,4,6-tribromoaniline followed by a coupling reaction with 2-naphthol (Wang et al., 2003). This gives a red powder which was crystallized from methanol solution leading to red prismatic crystals.