2-Hydroxybenzenaminium acetate

In the crystal, the molecules are linked by O—H⋯O and N—H⋯O hydrogen bonds into a three-dimensional network.


Structure description
In recent years, substituted anilines and their derivatives have been studied extensively for applications as antibacterials and in non-linear optical systems (Vivek & Murugakoothan, 2014). Aminophenols containing equal stoichiometries of -OH, and -NH 2 groups have been widely studied to understand the supramolecular synthons existing in their assemblies (Allen et al., 1997;Dey et al., 2004).
Here, we report the structure of 2-hydroxybenzenaminium acetate, C 6 H 8 NO + Á-C 2 H 3 O 2 À , 1, obtained from the reaction of 2-hydroxyaniline and acetic acid. The molecular structure of the title compound is shown in Fig.1. The asymmetric unit contains one 2-hydroxybenzenaminium cation and one acetate anion. The cation is protonated at the amine N atom (N1) and linked to the anion by an N-HÁ Á ÁO hydrogen bond ( Fig. 1 and Table 1).
The best planes through the 2-hydroxybenzenaminium cation and acetate anion are almost perpendicular to each other, subtending a dihedral angle of 79.23 (4) . The C-data reports OH bond length (C2-O1) of 1.3520 (9) Å is similar to that observed for structures containing 2-hydroxybenzenaminium as a cation [1.350 (3) Å ; Jin & Wang, 2013]. All bond lengths and angles in the 2-hydroxybenzenaminium cation are within normal ranges (Zhao, 2012).

Figure 1
Diagram showing the C 6 H 8 NO + cation and C 2 H 3 O 2 À anion linked by an N-HÁ Á ÁO interaction (shown as a dashed line). Displacement ellipsoids are drawn at the 50% probability level.

of Synthesis and crystallization
The title compound was prepared by heating of a mixture of 2-aminophenol (Alfa Aesar, purity 98%) and acetic acid. This mixture was obtained by dissolution and agitation under reflux for 3 h of 0.5 g of the 2-aminophenol and 0.27 g of acetic acid in a 1:1 stoichiometric ratio in a hot ethanolic solution (20 ml). After warming for a few minutes using a water bath, the solution was cooled and kept at room temperature. Within a few days, yellow needle-like crystals suitable for the X-ray analysis were obtained (yield 60%) by evaporation of the solution.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2.

data-1
IUCrData (  Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. Refinement. The hydrogen atoms of the NH 3 and hydroxyl groups were localized in the difference-Fourier map and refined with U iso (H) set to 1.5U eq (O) or 1.2U eq (N). All the other hydrogen atoms were placed in calculated positions with C-H = 0.95 Å for aromatic CH and C-H = 0.96 Å for CH 3 and refined using a riding model with fixed isotropic displacement parameters [U iso (H) = 1.2U eq (C-aromatic) and U iso (H) = 1.5U eq (C-methyl)].