1,3-Bis(2-ethoxyphenyl)triazene methanol 0.33-solvate

There are three independent molecules of 1,3-bis(2-ethoxyphenyl)triazene and a molecule of methanol in the asymmetric unit of the title compound, C16H19N3O2·0.33CH3OH. Two molecules related by a non-crystallographic pseudo-twofold rotation axis are linked via distinct intermolecular N—H⋯N hydrogen bonds, leading to the formation of a dimer with an R 2 2(8) graph set. The third molecule is connected to the methanol molecule by O—H⋯N and N—H⋯O hydrogen bonds. There are a number of weak C—H⋯π interactions, with H⋯π distances ranging from 2.74 to 2.89 Å between the C—H groups and the aromatic benzene rings.

There are three independent molecules of 1,3-bis(2-ethoxyphenyl)triazene and a molecule of methanol in the asymmetric unit of the title compound, C 16 H 19 N 3 O 2 Á0.33CH 3 OH. Two molecules related by a non-crystallographic pseudo-twofold rotation axis are linked via distinct intermolecular N-HÁ Á ÁN hydrogen bonds, leading to the formation of a dimer with an R 2 2 (8) graph set. The third molecule is connected to the methanol molecule by O-HÁ Á ÁN and N-HÁ Á ÁO hydrogen bonds. There are a number of weak C-HÁ Á Á interactions, with HÁ Á Á distances ranging from 2.74 to 2.89 Å between the C-H groups and the aromatic benzene rings.
The molecule A is almost planar, but the other two molecules (B and C) are somewhat twisted with respect to the phenyl rings. Two interlocked molecules (A and B) are connected by two distinct classic N-H···N hydrogen bonds with D···A of 3.024 (3) and 3.033 (3) Å and are related by a non-crystallographic pseudo twofold rotation axis. The N-H···N hydrogen bonds lead to the formation of a dimer with an R 2 2 (8) graph set geometry (Grell, et al., 2002). The steric demand of the ethoxy groups in the ortho position prevents a co-planar arrangement of the two molecules in the dimer which instead consists of two interlocked molecules. The third molecule (C) is connected to a methanol molecule by two O7-H7O···N7 and N9-H9N···O7 hydrogen bonds forming a six membered ring with an R 2 2 (6) graph set geometry (Grell, et al., 2002). Hydrogen bond geometries are shown in Table 1.
Also, there are several interesting weak C-H···π interactions between CH groups with aromatic phenyl rings with H···π distances ranging from 2.74 Å to 2.89 Å (Fig. 2). The unit cell packing of the title compound is presented in Fig. 3.

Experimental
A 100 ml flask was charged with 10 g of ice and 15 ml of water and then cooled to 273 K in an ice-bath. To this was added 10 mmol (1.37 g) of o-phenetidin and 13 mmol of hydrochloric acid (37%) followed by a solution containing NaNO 2 6 mmol (0.41 g) in 25 ml of water during a 15 min period. After mixing for 15 min a solution containing 180 mmol (14.76 g) of supplementary materials sup-2 sodium acetate in 45 ml of water was added. After mixing for 45 min the brown product was filtered and dissolved in Et 2 O, and was crystallized at 263 K. Recrystallization from methanol afforded the title compound as an orange crystalline material.

Refinement
The hydrogen atoms bonded to N and O were found from difference Fourier synthesis. All hydrogen atoms were included in the refinement at geometrically idealized positions in isotropic approximation in riding mode with distances: N/O-H = 0.88 Å, C-H = 0.95 (aryl), 0.98 (methyl), 0.99 (methylene) Å and U iso (H) equal to 1.5U eq (C) for methyl groups and 1.2U eq (N/O and methylene C). Fig. 1. Molecular structure of the title compound, with thermal elliposids drawn at 50% probability level. Only hydrogen atoms involved in the hydrogen bonding are shown.