(E)-1-[2-(2-Cyano­phen­yl)diazen-2-ium-1-yl]naphthalen-2-olate

Hassiba Bougueria; Mohamed Amine Benaouida; Sofiane Bouacida; Abd el kader Bouchoul

doi:10.1107/S1600536813017261

. 2013 Jun 29;69(Pt 7):o1175–o1176. doi: 10.1107/S1600536813017261

(E)-1-[2-(2-Cyanophenyl)diazen-2-ium-1-yl]naphthalen-2-olate

Hassiba Bougueria ^a,^*, Mohamed Amine Benaouida ^a, Sofiane Bouacida ^a, Abd el kader Bouchoul ^a

PMCID: PMC3770433 PMID: 24046718

Abstract

There are two independent zwitterion molecules (A and B) in the asymmetric unit of the title compound, C₁₇H₁₁N₃O, which belongs to the family of azo dyes. The dihedral angle between the benzene ring and the naphthalene ring system is 6.99 (6)° in molecule A and 4.38 (6)° in molecule B. The azo group adopts an E conformation with respect to the –N=N– bond and each of the independent molecules has an intramolecular N—H⋯O hydrogen bond. In the crystal, molecules are linked by C—H⋯O and C—H⋯N hydrogen bonds, forming ribbons propagating along [-110]. The ribbons are linked via π–π interactions involving the benzene and naphthalene rings of inversion-related A and inversion-related B molecules, forming a three-dimensional structure. The most significant centroid–centroid distances vary from 3.6599 (6) to 3.7538 (9) Å.

Related literature

For general background to azo compounds and their use in dyes, pigments and advanced materials, see: Lee et al. (2004 ▶); Oueslati et al. (2004 ▶). Many azo compounds have been synthesized by diazotization and diazo coupling reactions, see: Wang et al. (2003 ▶). For a related structure, see: Rãdulescu et al. (2006 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C₁₇H₁₁N₃O
M _r = 273.29
Triclinic,
a = 7.1296 (3) Å
b = 12.9532 (7) Å
c = 15.6181 (8) Å
α = 111.562 (2)°
β = 90.536 (2)°
γ = 100.779 (2)°
V = 1312.92 (11) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 150 K
0.55 × 0.11 × 0.08 mm

Data collection

Bruker APEXII diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2002 ▶) T _min = 0.910, T _max = 0.993
18729 measured reflections
6021 independent reflections
3859 reflections with I > 2σ(I)
R _int = 0.037

Refinement

R[F ² > 2σ(F ²)] = 0.046
wR(F ²) = 0.120
S = 1.06
6021 reflections
387 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.20 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: SAINT (Bruker, 2006 ▶); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); 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/S1600536813017261/su2616sup1.cif

e-69-o1175-sup1.cif^{(35.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813017261/su2616Isup2.hkl

e-69-o1175-Isup2.hkl^{(294.7KB, hkl)}

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

Supplementary material file. DOI: 10.1107/S1600536813017261/su2616Isup3.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
N2—H2⋯O1	0.92 (1)	1.80 (2)	2.5380 (16)	136 (2)
N5—H5⋯O2	0.90 (1)	1.72 (2)	2.5277 (17)	147 (2)
C21—H21⋯N3ⁱ	0.93	2.61	3.509 (2)	162
C30—H30⋯N3ⁱⁱ	0.93	2.60	3.487 (2)	159
C32—H32⋯O1ⁱⁱⁱ	0.93	2.49	3.1994 (18)	133

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

We thank all researchers of the CHEMS Research Unit of the University of Constantine, Algeria, for the valuable assistance they have provided us throughout the realisation of this work. We also express our gratitude and thank Mr. L Ouahab, Director of Research at laboratory UMR LCSIM 6511, CNRS, Rennes I (France), for his valuable collaboration in the recording and interpretation of the XRD data.

supplementary crystallographic information

Comment

Azo dno's (dyes and pigments) are by far the most important class of dno's, accounting for over 50% of all commercial dno's, and having been studied more than any other class of dye. Azo dno's contain at least one azo group (–N=N–) but can contain two (diazo), three (triazo), or more but rarely, four (tetrakisazo) or more (polyazo) azo groups. The azo group is attached to two groups of which at least one, but more usually both, are aromatic. They exist in the trans form in which the band angle vis. 120°; the nitrogen atoms are sp² hybridized. Almost without exception, azo dno's are made by diazotization of a primary aromatic amine followed by coupling of the resultant diazonium salt with an electron-rich nucleophile (Wang et al., 2003). We report herein on the crystal structure of the title compound, obtained through the diazotization of 2-cyanoaniline followed by a coupling reaction with 2-naphthol.

The molecular structure of the title compound is shown in Fig. 1. The asymmetric unit contains two independent molecules (A and B) with no significant differences in their structures. The bond distances (Allen et al., 1987) and bond angles in the two molecules are normal and similar to those in a related compound (Rãdulescu et al., 2006). Interestingly, the hydrogen atom of the OH group has been transfered to the N atom in the azo group to form a zwitterion, and in each of the independent molecules there is an intramolecular N—H···O hydrogen bond (Table 1). The molecules are relatively planar with the dihedral angle between the benzene ring and naphthalene ring system being 6.99 (6) ° in A and 4.38 (6) ° in B. Both molecules have an E conformation with respect to azo bridge (Fig. 1). The C1-N1-N2-C11 torsion angle is -175.64 (12) ° in A and the C18–N4–N5–C28 torsion angle is-177.81 (13)° in B, confirming the trans conformation of the C atom with respect to hydrazine N atom.

In the crystal, molecules are linked by C-H···O and C-H···N hydrogen bonds forming ribbons propagating along [-110]; see Table 1 and Fig. 2. The ribbons are linked via π-π interactions involving the benzene and naphthalene rings of inversion related A and inversion related B molecules. The most significant centroid-to-centroid distances are Cg1···Cg3ⁱ and Cg2···Cg3ⁱ = 3.6636 (9) and 3.7538 (9) Å, respectively, for the A molecules, and Cg5···Cg7ⁱⁱ and Cg6···Cg7ⁱⁱ = 3.6599 (6) and 3.6610 (9) Å, respectively, for the B molecules [Cg1, Cg2, Cg3, Cg5, Cg6 and Cg7 are the centroids of the C1-C5/C10, C5-C10, C11-C16, C18-C22/C27, C22-C27 and C28-C30 rings, respectively; symmetry codes: (i) -x+1, -y, -z; (ii) -x, -y, -z+1].

Experimental

The title compound was obtained through the diazotization of 2-cyanoaniline followed by a coupling reaction with 2-naphthol, according to the literature procedure used to synthesize other aromatic azo-compounds (Wang et al., 2003). Orange rod-like crystals of the title compound were obtained by slow evaporation at room temperature of a solution in H₂O/THF (1/1 v/v).