Dibromido(di-2-pyridylamine-κ2 N 2,N 2′)platinum(II)

The PtII ion in the title complex, [PtBr2(C10H9N3)], is four-coordinated in an essentially square-planar environment by two N atoms from a chelating di-2-pyridylamine (dpa) ligand and two Br− anions. The dpa ligand is not planar, with the dihedral angle between the pyridine rings being 40.8 (2)°. The complex molecules are stacked in columns along [001] through π–π interactions between the pyridine rings [centroid–centroid distances = 3.437 (3) and 3.520 (3) Å]. Intermolecular N—H⋯Br hydrogen bonds connect the molecules into chains running along [010]. Intramolecular C—H⋯Br interactions are also observed.

The Pt II ion in the title complex, [PtBr 2 (C 10 H 9 N 3 )], is fourcoordinated in an essentially square-planar environment by two N atoms from a chelating di-2-pyridylamine (dpa) ligand and two Br À anions. The dpa ligand is not planar, with the dihedral angle between the pyridine rings being 40.8 (2) . The complex molecules are stacked in columns along [001] through interactions between the pyridine rings [centroidcentroid distances = 3.437 (3) and 3.520 (3) Å ]. Intermolecular N-HÁ Á ÁBr hydrogen bonds connect the molecules into chains running along [010]. Intramolecular C-HÁ Á ÁBr interactions are also observed.
The Pt II ion is four-coordinated in an essentially square-planar environment by two N atoms from a chelating dpa ligand and two Branions ( Fig. 1). The Pt-N and Pt-Br bond lengths are nearly equivalent, respectively ( Table 1). The dpa ligand is not planar. The dihedral angle between the least-squares planes of the pyridine rings is 40.8 (2)°. In the crystal, the complex molecules are stacked in columns along [001] through π-π interactions between the pyridine rings [centroidcentroid distances = 3.437 (3) and 3.520 (3) Table 2). Intramolecular C-H···Br hydrogen bonds are also observed.

Experimental
To a solution of K 2 PtBr 4 (0.2326 g, 0.392 mmol) in H 2 O (20 ml) and MeOH (10 ml) was added di-2-pyridylamine (0.0722 g, 0.422 mmol) and stirred for 7 h at room temperature. The formed precipitate was separated by filtration, washed with H 2 O and acetone and dried at 50°C to give a yellow powder (0.1502 g). Crystals suitable for X-ray analysis were obtained by slow evaporation from an acetone solution.

Refinement
C-bound H atoms were positioned geometrically and allowed to ride on their respective parent atoms [C-H = 0.95 Å and U iso (H) = 1.2U eq (C)]. N-bound H atom was located from a difference Fourier map and allowed to ride on its parent atom in the final cycles of refinement, with N-H = 0.92 Å and U iso (H) = 1.5U eq (N). The highest peak (1.41 e Å -3 ) and the deepest hole (-2.22 e Å -3 ) in the difference Fourier map are located 0.73 and 0.79 Å from Pt1 atom, respectively.

Computing details
Data collection: SMART (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008  Molecular structure of the title complex, with displacement ellipsoids 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq