4-Methoxyanilinium bromide

The title compound, C7H10NO+·Br−, consists of almost planar 4-methoxyanilinium cations, wherein the O atom lies 0.049 (3) Å out of the plane formed by the non-H atoms, and a Br− anion. Strong N—H⋯Br and N—H⋯(Br,Br) hydrogen bonding contributes to the stability of the crystal structure and links the cations and anions into a three-dimensional network.

The title compound, C 7 H 10 NO + ÁBr À , consists of almost planar 4-methoxyanilinium cations, wherein the O atom lies 0.049 (3) Å out of the plane formed by the non-H atoms, and a Br À anion. Strong N-HÁ Á ÁBr and N-HÁ Á Á(Br,Br) hydrogen bonding contributes to the stability of the crystal structure and links the cations and anions into a threedimensional network.

Comment
This study is a part of systematic investigation of dielectric-ferroelectric materials, including organic ligands (Li et al., 2008), metal-organic coordination compounds (Hang et al., 2009) and organic-inorganic hybrids. The title compound, 4methoxyanilinium bromide, (I), has no dielectric disuniform from 80 K to 450 K, (m.p. 458-459 K). In this article, the crystal structure of (I) has been presented.
The asymmetric unit of the title compound is built up from an almost planar 4-methoxybenzenamine cation wherein O1 lies 0.049 (3) Å out of the plane formed by its non-hydrogen atoms and a Branion ( Fig. 1). The strong N-H···Br hydrogen bonding (N···Br distances 3.300 (3)-3.430 (3) Å) contribute to the stability of the crystal structure and lead the cations and anions to tridimensional network (Fig 2). The crystal structures containing 4-methoxybenzenamine cation have been reported (Tan et al., 2006;Soumhi et al., 2006;Ben Amor et al., 1995).

Experimental
Single crystals of 4-methoxyanilinium bromide were prepared by slow evaporation at room temperature of an ethanol solution of 4-methoxybenzenamine and hydrobromic acid.

Refinement
Positional parameters of all the H atoms were calculated geometrically and were allowed to ride on the C atoms to which they are bonded, with U iso (H) = 1.2U eq (C). Fig. 1

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 > σ(F 2 ) is used only for calculating Rfactors(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.