1,4-Diazoniabicyclo[2.2.2]octane tetrachloridocadmate(II) monohydrate

The asymmetric unit of the title compound (C6H14N2)[CdCl4]·H2O contained one 1,4-diazabicyclo[2.2.2]octane dication, a tetrahedral CdCl4 2− anion and a lattice water molecule. In the crystal, the solvate water molecule interacts with the cationic and anionic species via N—H⋯O and O—H⋯Cl [O⋯Cl = 3.289 (7) Å] hydrogen-bond interactions, respectively, leading to a layered supramolecular structure extending parallel to (011).

Supporting information for this paper is available from the IUCr electronic archives (Reference: DS2238).

Comment
In recent years, a significant number of organic-inorganic hybrid materials based on metal halide units have been prepared and studied (Lemmerer & Billing, 2012). It has been shown that their structures can vary considerably, ranging from systems based on isolated polyhydra to ones containing extended chains and up to two-or three-dimensional networks (Ben Rhaiem et al., 2013;Samet et al., 2010;Billing & Lemmerer, 2009). Generally, the organic cations contain ammonium groups linked to the anionic framework by hydrogen bonds via halogenous tetrahedral vertices (Sun & Qu, 2005) and (Zhang & Zhu, 2012). In pseudopolymorphic cases, the water molecules can be able to coordinate the charged components strengthening the crystal cohesion as it was observed in (dabcoH 2 )CuCl 4 and (dabcoH 2 )CuCl 4 ·H 2 O (Wei & Willett, 2002). The protonated N2 atom of the organic cation interacts via a simple hydrogen bond with oxygen atom of the water molecule ( Fig. 3 and Tab. 1).

Experimental
The title compound (C 6 H 14 N 2 ) [CdCl 4 ]·H 2 O, (I), was obtained by the reaction of cadmium iodide CdI 2 (0.19 g, 0.5 mmol) with DABCO (1,4-diazabicyclo[2.2.2]octane) (0.112 g, 1 mmol) in aqueous hydrochloric acid solution with pH ranging between 3 and 4. The mixture was stirred for several minutes. Colorless crystals suitable for X-ray diffraction analysis were obtained by slow evaporation at room temperature over 2 weeks.

Refinement
Hydrogen water molecules are omited.  Packing diagram of (I), projected along the a axis.

Figure 2
The asymmetric unit of (I), showing the atom numbering scheme. Displacement ellipsoids are drawn at 50% probability level and H atoms are shown as small spheres of arbitrary radii.   where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 1.58 e Å −3 Δρ min = −1.44 e Å −3 Special details Experimental. Number of psi-scan sets used was 5 Theta correction was applied. Averaged transmission function was used. No Fourier smoothing was applied. 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.