Tetraammineplatinum(II) dichloride ammonia tetrasolvate

The title compound, [Pt(NH3)4]Cl2·4NH3, was crystallized in liquid ammonia from the salt PtCl2. The platinum cation is coordinated by four ammonia molecules, forming a square-planar complex. The chloride anions are surrounded by nine ammonia molecules, either bound within the platinum complex or solvent molecules. The solvent ammonia molecules are packed in such a way that an extended network of N—H⋯N and N—H⋯Cl hydrogen bonds is formed. The structure is isotypic with [Pd(NH3)4]Cl2·4NH3 [Grassl & Korber (2014). Acta Cryst. E70, i32].

The title compound, [Pt(NH 3 ) 4 ]Cl 2 Á4NH 3 , was crystallized in liquid ammonia from the salt PtCl 2 . The platinum cation is coordinated by four ammonia molecules, forming a squareplanar complex. The chloride anions are surrounded by nine ammonia molecules, either bound within the platinum complex or solvent molecules. The solvent ammonia molecules are packed in such a way that an extended network of N-HÁ Á ÁN and N-HÁ Á ÁCl hydrogen bonds is formed. The structure is isotypic with [Pd(NH 3 ) 4 ]Cl 2 Á4NH 3 [Grassl & Korber (2014). Acta Cryst. E70, i32].
Supporting information for this paper is available from the IUCr electronic archives (Reference: PK2522). The crystal structure of the title compound was determined in the course of investigations regarding the reactivity of carbohydrates towards metal cations in liquid ammonia.
In the crystal structure the platinum cation forms a homoleptic ammine complex with a square-planar coordination geometry. The Pt-N bond lengths are 2.0471 (16) Å and 2.0519 (15) Å, respectively. This is in good accordance with the bond lengths given by Smolentsev et al. (2010). The angles N-Pt-N are 89.24 (6)° and 90.76 (6)°, and within the complex, ammonia ligands opposite to each other have staggered hydrogen atom positions (Fig 1).
The chloride anion shows nine direct contacts to hydrogen atoms of ammonia molecules either bound in the complex or to solvate molecules, forming a network of hydrogen bonds ( Fig. 2 and Fig. 3). The N-H···Cl bond angles range between 154 (2)° and 173 (2) vessel and 40 ml of dry liquid ammonia were condensed. The mixture was stored at 237 K for one week to ensure that all substances were completely dissolved. The flask was then stored at 161 K for five months. After that period, clear colorless crystals of the title compound were found at the bottom of the flask.

Refinement
The crystal structure does not show any features where special refinement methods have to be applied. All hydrogen atoms could be located in difference map and both bond angle/bond length and isotropic displacement parameters were refined.  Crystal structure of the title compound with labeling and displacement ellipsoids drawn at the 50% probability level.

Figure 2
The chloride anion is shown with its surrounding molecules. The predominant bond type is hydrogen bonding. Displacement ellipsoids are drawn at the 50% probability level.  Extended network of hydrogen bonds in the crystal structure. The solvent ammonia molecules are oriented to optimize the hydrogen bond geometry. Displacement ellipsoids are drawn at the 50% probability level. 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.