3-Cyano-N-(2-hydroxybenzyl)anilinium nitrate

In the crystal structure of the title compound, C14H13N2O+·NO3 −, N—H⋯O and O—H⋯O hydrogen bonds link cations and anions into a two-dimensional network parallel to (100). The dihedral angle between the rings is 9.48 (2)°.

In the crystal structure of the title compound, C 14 H 13 N 2 O + Á-NO 3 À , N-HÁ Á ÁO and O-HÁ Á ÁO hydrogen bonds link cations and anions into a two-dimensional network parallel to (100). The dihedral angle between the rings is 9.48 (2) .

Comment
Salts of amine attracted more attention as phase transition dielectric materials for its application in memory storage (Fu et al. 2007;Fu & Xiong 2008;Fu et al. 2008;Fu et al. 2009). With the purpose of obtaining phase transition crystals of 3-(2-hydroxybenzylamino)benzonitrile salts, its interaction with various acids has been studied and we have elaborated a series of new materials with this organic molecule. In this study, we describe the crystal structure of the title compound, 3-cyano-N-(2-hydroxybenzyl)anilinium nitrate.
The dielectric constant of title compound as a function of temperature indicates that the permittivity is basically temperature-independent, suggesting that this compound should be not a real ferroelectrics or there may be no distinct phase transition occurred within the measured temperature range. Similarly, below the melting point (438 K) of the compound, the dielectric constant as a function of temperature also goes smoothly, and there is no dielectric anomaly observed (dielectric constant ranging from 6.1 to 7.3).
The asymmetric unit is composed of one NO 3 anion and one C 14 H 13 ON 2 + cation (Fig.1). The amine N atom was protonated, thus indicating a positive charge. And the NO 3 anion was showing a negative charge to make the charge balance.
The geometric parameters of the title compound are in the normal range.
In the crystal structure, all the H atoms of N atom and the hydroxyl are involved in hydrogen bonds. One of the H atom of the NH 2 group is giving a bifurcated N-H···O hydrogen bonds with O3 and O4 atoms of NO 3 -, respectively. The another H atom of the NH 2 group and the H atoms of hydroxyl are involved in N-H···O and O-H···O hydrogen bonds with the O2 atom of the NO 3 -. These hydrogen bonds link the ionic units into a two-dimentional network parallel to the (1 0 0) plane. (Table 1 and Fig.2).

Experimental
The commercial 3-(2-hydroxybenzylamino)benzonitrile (3 mmol) was dissolved in water/HNO 3 (50:1 v/v) solution. The solvent was slowly evaporated in air affording colourless block-shaped crystals of the title compound suitable for X-ray analysis.

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. 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 > 2sigma(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.