Bis(2,3-dimethylanilinium) tetrachloridozincate dihydrate

In the title compound, (C8H12N)2[ZnCl4]·2H2O, the Zn atom is coordinated by four Cl atoms in a tetrahedral geometry. The water molecules and the organic cations interact with the [ZnCl4]2− complex anions, building up a two-dimensional hydrogen-bonded network parallel to (100).

In the title compound, (C 8 H 12 N) 2 [ZnCl 4 ]Á2H 2 O, the Zn atom is coordinated by four Cl atoms in a tetrahedral geometry. The water molecules and the organic cations interact with the [ZnCl 4 ] 2À complex anions, building up a two-dimensional hydrogen-bonded network parallel to (100).

Experimental
Crystal data (C 8

Comment
Aniline is an useful chemical product used in various areas. Some derivatives of aniline have improving anticorrosion ability for metals (Wang et al., 2002), others show high efficiency as chemical sensors (MacDiamid et al.,1998) and catalitic oxidation (Hirao & Fukuhara, 1998). Bibliography reports some structures where the cation dimethylanilinium is associated to other anions as sulfate (Singh et al., 2002), nitrate, perchlorate (Singh et al., 1995), chloride (Linden et al., 1995), and phosphate (Fábry et al., 2002). We report here a crystal structure where this organic cation is associated to an anionic complex (I).
The asymmetric unit consists of two 2,3-dimethylanilinium cations, two water molecules and one complex an- These values indicate that the coordination geometry of the Zn atom can be considered as being a slightly distorted tetrahedron (Harrison, 2005). The nearst Zn···Zn intra-chain separation is 7.135 (1) Å, while the distance between adjacent chains is 11.050 (2) Å. The examination of the organic cations shows that the value distances and angles show no significant difference from those obtained in other crystals involving the same organic groups (Marouani et al., 2010). The phenyl rings of these cations are planar with a maximum atomic deviation of 0.00025 Å and a dihedral angle between them of 21.95°.

Experimental
A mixture of an aqueous solution of 2,3-xylidine, HCl and ZnCl 2 in a 2:2:1 molar ratio was prepared, stirred then slowly evaporated at room temperature (293 K). After few days, colourless prismatic crystals of (C 16 H 28 N 2 ) [ZnCl 4 ].H 2 O appear with suitable size for x-ray diffraction measurements.

Refinement
All H atoms attached to C atoms and N atom were fixed geometrically and treated as riding with C-H = 0.96 Å (methyl) or 0.93 Å (aromatic) and N-H = 0.89 Å with U iso (H) = 1.2U eq (C aromatic ) or U iso (H) = 1.5U eq (C methyl ,N). H atoms of water molecule were located in difference Fourier maps and included in the subsequent refinement using restraints (O-H= supplementary materials sup-2 0.82 (1)Å and H···H= 1.37 (2)Å) with U iso (H) = 1.5U eq (O). In the last cycle of refinement, they were treated as riding on their parent O atoms. Fig. 1. The assymetric unit of the title compound, with the atom numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are represented as small sphere of arbitrary radii. Hydrogen bonds are shown as dashed lines.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq