1-(3,5-Dichlorophenyl)-3-(2-methoxyphenyl)triaz-1-ene

The title molecule, C13H11Cl2N3O, is almost planar and adopts a trans conformation with respect to the –N=N– bond; the dihedral angle between the rings is 3.47 (2)°. The N—N bond lengths indicate the presence of single- and double-bond characters and hence the –N=N—NH– moiety. In the crystal, inversion dimers linked by pairs of N—H⋯Cl hydrogen bonds occur, and C—H⋯π and π–π stacking interactions are also observed.

The title molecule, C 13 H 11 Cl 2 N 3 O, is almost planar and adopts a trans conformation with respect to the -N N-bond; the dihedral angle between the rings is 3.47 (2) . The N-N bond lengths indicate the presence of single-and double-bond characters and hence the -N N-NH-moiety. In the crystal, inversion dimers linked by pairs of N-HÁ Á ÁCl hydrogen bonds occur, and C-HÁ Á Á andstacking interactions are also observed.

Related literature
For background literature and the synthesis of related compounds, see: Rofouei et al. (2009). For the synthesis and molecular structure of a similar monochloro-substituted triazene, see: Rofouei et al. (2012).  Table 1 Hydrogen-bond geometry (Å , ).

Experimental
Cg1 is the centroid of the C2-C7 ring.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: PV2511). In continuation of our studies on the synthesis and characterization of trizene compounds as ligands in our laboratory (Rofouei et al., 2012;Rofouei et al., 2009), we now report the crystal structure of the title compound.
The title molecule ( Fig. 1) adopts trans configuration about the (-N2═N3-) bond and is almost planar with the dihedral angel between two aromatic rings 3.47 (2) °. Non-Classic N-H···Cl hydrogen bond with D···A distance of 3.529 (2) Å connect the individual molecules into dimers. The N1-N2 and N2-N3 bond distances are 1.323 (3) and 1.256 (3) Å, which indicate the presence of a single and a double bond characters, respectively. Another interesting feature of the title compound is the presence of π-π [Cg1···Cg1 distance of 3.757 (2) Å] and edge-to-face C1-H1C···Cg1 stacking interactions between the methoxy hydrogen and the phenyl ring with H···π distance of 2.76 Å, in which Cg1 is the center of (C2-C7) ring. Unit cell packing diagram of the title compound is presented in Fig. 2, showing N-H···Cl hydrogen bonds.

Experimental
To a 1 L flask in an ice bath, was added dichloroaniline (6.36 g, 0.05 mol) and HCl (4.68 g, 0.13 mol; d = 1.18 g.ml -1 ). To the obtained solution was added dropwise a solution of sodium nitrite (4.14 g in 25 ml H 2 O). Then, a diluted solution of o-anisidine (6.15 g, 0.05 mol) in methanol (10 ml) was added to the solution. The pH of the solution was adjusted at about 7-8 by adding a solution of sodium acetate ( 14.76 g, 0.18 mol) in 45 ml H 2 O as solvent. The solution was stirred for about 45 minutes, giving an orange precipitate. It was then filtered off and dried under vacuum. After dissolving in dichloromethane and recrystallization, orange crystals of the title compound were obtained.

Refinement
N-H hydrogen atom were found in a difference Fourier map and refined isotropically with distance restraint of 0.85 (2) Å. All C-H hydrogen atoms were positioned geometrically and refined as riding atoms with C-H = 0.93 and 0.96 Å, U iso (H) = 1.2U eq (C) and 1.5U eq (C) for aryl and methyl H atoms, respectively.

Figure 2
Part of the unit-cell packing of the title compound showing C-H···π interactions between a methoxy H atom and the phenyl ring with a H···π distance of 2.76 Å.

1-(3,5-Dichlorophenyl)-3-(2-methoxyphenyl)triaz-1-ene
Crystal data Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.