Bis(di-2-pyridylamine-κ2 N 2,N 2’)platinum(II) dibromide monohydrate

The asymmetric unit of the title compound, [Pt(C10H9N3)2]Br2·H2O, contains two crystallographically independent half-molecules of the cationic PtII complex, two Br− anions and a lattice water molecule; an inversion centre is located at the centroid of each complex. Each PtII ion is four-coordinated in an essentially square-planar environment by four pyridine N atoms derived from the two chelating di-2-pyridylamine (dpa) ligands, and the PtN4 unit is exactly planar. The chelate ring formed by the dpa ligand displays a boat conformation, with dihedral angles between the pyridine rings of 35.9 (2) and 41.0 (2)°. The complex cations, Br− anions and solvent water molecules are linked by O—H⋯Br, N—H⋯Br, C—H⋯O and C—H⋯Br hydrogen bonds, forming a three-dimensional network.

The asymmetric unit of the title compound, [Pt(C 10 H 9 N 3 ) 2 ]-Br 2 ÁH 2 O, contains two crystallographically independent halfmolecules of the cationic Pt II complex, two Br À anions and a lattice water molecule; an inversion centre is located at the centroid of each complex. Each Pt II ion is four-coordinated in an essentially square-planar environment by four pyridine N atoms derived from the two chelating di-2-pyridylamine (dpa) ligands, and the PtN 4 unit is exactly planar. The chelate ring formed by the dpa ligand displays a boat conformation, with dihedral angles between the pyridine rings of 35.9 (2) and 41.0 (2) . The complex cations, Br À anions and solvent water molecules are linked by O-HÁ Á ÁBr, N-HÁ Á ÁBr, C-HÁ Á ÁO and C-HÁ Á ÁBr hydrogen bonds, forming a three-dimensional network.
The asymmetric unit contains two crystallographically independent half-molecules of the cationic Pt II complex, two Branions and a lattice water molecule; an inversion centre is located at the centroid of each complex (Fig. 1). The two complexes are chemically identical, but slightly different in geometry. The Pt II ion in each complex is four-coordinated in an essentially square-planar environment by four pyridine N atoms derived from the two chelating dpa ligands, and the PtN 4 unit is exactly planar. The dpa ligands display a boat conformation with dihedral angles between the least-squares planes of the two pyridine rings of 35.9 (2)° in complex with Pt1 and 41.0 (2)° in complex with Pt2. The Pt-N bond lengths are nearly equivalent [Pt-N: 2.013 (5)-2.030 (5) Å] ( Table 1). The complex cations, Branions and solvent water molecules are linked by intermolecular O-H···Br, N-H···Br, C-H···O and C-H···Br hydrogen bonds, forming a three-dimensional network ( Fig. 2 and Table 2). The complex cations are stacked into columns along the a axis and show a number of intermolecular π-π interactions between the pyridine rings, with a shortest ring centroid-centroid distance of 3.951 (4) Å.

Experimental
To a solution of K 2 PtBr 6 (0.1016 g, 0.135 mmol) in H 2 O (10 ml) and MeOH (10 ml) was added di-2-pyridylamine (0.0479 g, 0.280 mmol) and stirred for 7 h at room temperature. The formed precipitate was separated by filtration and washed with H 2 O and MeOH, and dried at 50 °C, to give an orange powder (0.0450 g). Crystals suitable for X-ray analysis were obtained by slow evaporation from an N,N-dimethylformamide (DMF) solution at 60 °C.

Refinement
Carbon-bound H atoms were positioned geometrically and allowed to ride on their respective parent atoms: C-H = 0.95 Å with U iso (H) = 1.2U eq (C). Nitrogen-and oxygen-bound H atoms were located from the difference Fourier map then

Figure 1
A structure detail of the title compound, with displacement ellipsoids drawn at the 50% probability level for non-H atoms. Unlabelled atoms are generated by the application of the inversion centers.  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.