Bis(1,10-phenanthrolin-1-ium) tetrachloridozincate monohydrate

In the crystal structure of the title compound, (C12H9N2)2[ZnCl4]·H2O, the two independent 1,10-phenanthrolinium cations are bridged by the water molecule and the tetrahedral tetrachloridozincate anion via N—H⋯O, O—H⋯Cl and N—H⋯Cl hydrogen bonds, forming chains along [100]. The chains are linked via C—H⋯Cl hydrogen bonds and a number of π–π interactions [centroid–centroid distances vary from 3.5594 (14) to 3.7057 (13) Å], forming a three-dimensional network. In each 1,10-phenanthrolinium cation, there is a short N—H⋯N interaction.


Related literature
For an example of the crystal structure of a hybrid compound combining an organic cation and the tetrachloridozincate anion, see: Dong & Liu (2012). For details of the Cambridge Structural Database, see: Allen (2002).

Comment
As part of an ongoing investigation of the structures of and non-covalent interactions present in self-assembling organic and inorganic hybrid materials prepared by the combination of an organic cation and the tetrachloridozincate anion we synthesized the title compound. There are only a small number of structures of materials containing bis(1,10phenanthrolinium) cations and perhalometallate anions in the Cambridge Structural Database (CSD; V5.35, last update Nov. 2013;Allen, 2002), and none of them involve the tetrachloridozincate anion.
The molecule structure of the title compound is shown in Fig. 1. The asymmetric unit contains one inorganic tetrachloridozincate anion and two 1,10-phenanthrolinium organic cations. The compound crystallized as a monohydrate.
In the crystal, the two independent 1,10-phenanthrolinium cations are bridged by the water molecule and the tetrachloridozinc anion via N-H···O, O-H···Cl and N-H···Cl hydrogen bonds (Table 1 and (Table 1) and a number of π-π interactions forming a threedimensional network.

Experimental
Zinc chloride (136 mg, 1 mmol) was dissolved in 10 mL of water. To this 1,10-phenanthroline (396 mg, 2 mmol) in 20 ml of an EtOH/HCl mixture (1:9 v/v) was added drop wise. The mixture was heated to 323 K for 2-3 hrs and then allowed to stand. On slow evaporation colourless crystals separated out. They were filtered off and recrystallized using acidified water.

Refinement
The NH and water H atoms were located in a difference Fourier map and freely refined. The C bound H atoms were positioned geometrically and allowed to ride on their parent atoms: C-H = 0.93 Å with U iso (H) = 1.2U eq (C).

Figure 1
The molecular structure of the title compound, with the atom labelling. Displacement ellipsoids are drawn at 30% probability level.   Table 1 for details).

Bis(1,10-phenanthrolin-1-ium) tetrachloridozincate monohydrate
Crystal data (C 12 (5) Special details Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles 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.