(Di-2-pyridylamine-κ2 N 2,N 2′)diiodidoplatinum(II)

The PtII ion in the title complex, [PtI2(C10H9N3)], is four-coordinated in a distorted square-planar environment defined by the two pyridine N atoms of the chelating di-2-pyridylamine (dpa) ligand and by two I− anions. The dpa ligand is not planar, the dihedral angle between the pyridine rings being 52.8 (3)°. Pairs of complex molecules are assembled through intermolecular N—H⋯I hydrogen bonds, forming a dimer-type species. The complexes are stacked in columns along the b axis and display several intermolecular π–π interactions between the pyridine rings, with a shortest ring centroid–centroid distance of 3.997 (5) Å.

The Pt II ion in the title complex, [PtI 2 (C 10 H 9 N 3 )], is fourcoordinated in a distorted square-planar environment defined by the two pyridine N atoms of the chelating di-2-pyridylamine (dpa) ligand and by two I À anions. The dpa ligand is not planar, the dihedral angle between the pyridine rings being 52.8 (3) . Pairs of complex molecules are assembled through intermolecular N-HÁ Á ÁI hydrogen bonds, forming a dimertype species. The complexes are stacked in columns along the b axis and display several intermolecularinteractions between the pyridine rings, with a shortest ring centroidcentroid distance of 3.997 (5) Å .
Two complex molecules are assembled through intermolecular N-H···I hydrogen bonds, forming a dimer-type species ( Fig. 2 and Table 2). The complexes are stacked in columns along the b axis and display several intermolecular π-π interactions between the pyridine rings, with a shortest ring centroid to centroid distance of 3.997 (5) Å.

Experimental
To a solution of K 2 PtCl 4 (0.2082 g, 0.502 mmol) in H 2 O (20 ml) and MeOH (10 ml) were added KI (0.7022 g, 4.230 mmol) and di-2-pyridylamine (0.0896 g, 0.523 mmol) and stirred for 3 h at room temperature. The formed precipitate was separated by filtration and washed with H 2 O and MeOH, and dried at 373 K, to give a yellow powder (0.2614 g).
Crystals suitable for X-ray analysis were obtained by slow evaporation from a CH 3 CN/acetone solution.

Refinement
Carbon-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)]. The nitrogen-bound H atom was located from Fourier difference maps and then allowed to ride on its parent atom in the final cycles of refinement with N-H = 0.92 Å and U iso (H) = 1.5 U eq (N). The highest peak (1.47 e Å -3 ) and the deepest hole (-1.31 e Å -3 ) in the difference Fourier map are located 0.56 Å and 0.67 Å from the atoms Pt1 and I1, respectively.

Computing details
Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); 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). The molecular structure of the title complex, with displacement ellipsoids drawn at the 50% probability level for all non-H atoms.  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.