Bis(2-methoxyanilinium) hexabromidostannate(IV) dihydrate

The asymmetric unit of the title compound, (C7H10NO)2[SnBr6]·2H2O, contains one cation, one half-dianion and one lattice water molecule. The [SnBr6]2− dianion, located on an inversion center, exhibits a highly distorted octahedral coordination environment, with Sn—Br bond lengths ranging from 2.2426 (9) to 3.0886 (13) Å. In the crystal, O—H⋯Br, N—H⋯Br, N—H⋯O and C—H⋯Br hydrogen bonds consolidate the packing, which can be described as consisting of alternating anionic (containing dianions and lattice water molecules) and cationic layers parallel to ab plane.


Related literature
For general background to hybrid organic-inorganic compounds, see: Kagan et al. (1999); Raptopoulou et al.

Experimental
Crystal data (C 7 H 10  H atoms treated by a mixture of independent and constrained refinement Á max = 1.51 e Å À3 Á min = À1.44 e Å À3 Table 1 Hydrogen-bond geometry (Å , ). Hybrid organic-inorganic compounds are of great interest owing to their ionic, electrical, magnetic and optical properties (Kagan et al., 1999;Raptopoulou et al., 2002). As a continuation of our structural study of such hydrid compounds containing 2-methoxyanilinium cation (Karoui et al., 2013), we report herein the crystal structure of the title compound (I).
The asymmetric unit of (I) contains one 2-methoxyanilinium cation, one-half dianion and one crystalline water molecule ( Fig. 1 2). Bond lengths and angles within the cations and dianions are as expected and comparable with those observed in the related compounds (Benali-Cherif et al., 2007;Karoui et al., 2013;Guelmami et al., 2007;Souissi et al., 2011;Smith et al., 2006;Tudela & Khan, 1991;Chouaib et al., 2013). The phenyl ring is practically planar with the greatest deviation from the six-atoms least squares plane being 0.0156 Å. The torsion angle O1-C1-C2-N1 is 2 (2)° indicating that the N1-C2 and C1-O1 groups deviate from the phenyl ring plane. The methoxy group of the organic cation makes an angle of 0(2)° with the plane of the phenyl ring and is in short intramolecular contact with O1 (N···O =2.824 (14) Å). The benzene ring is regular with C-C-C angles in agreement with the expected sp2 hybridation.
In the crystal, intermolecular O-H···Br, N-H···Br, N-H···O and C-H···Br hydrogen bonds (Table 1) consolidate the packing (Fig. 3), which can be described as consisting of alternating anionic (containing dianions and crystalline water molecules) and cationic layers parallel to ab plane.

Experimental
(C 7 H 10 NO) 2 SnBr 6 ·2H 2 O was prepared by refluxing during 5 h a solution of metallic tin (3 g, 25 mmol) in 40 ml an aqueous solution of hydrobromic acid, HBr 47%. To this solution, 9.5 ml (75 mmol) of a solution of 2-methoxyanilin was added at reflux temperature. After a slow solvent evaporation yellow crystals suitable for X-ray analysis were obtained.
They were washed with diethyl ether and dried over P 2 O 5 .

Refinement
All H atoms were geometrically positioned and treated as riding on their parent atoms, with C-H = 0.93 Å for the phenyl, 0.96 Å for the methyl and N-H= 0.89 Å with U iso (H)= 1.2 U eq (C-phenyl, N) or 1.5 U eq (C-methyl). The water H atoms were located in a difference Fourier map and refined using DFIX restraints (O-H 0.88 (7)

Figure 1
A view of the asymmetric unit of (I) showing the atomic numbering and 50% probability displacement ellipsoids   A portion of the crystal packing showing the hydrogen bonds as red dashed lines.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 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.