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

Kwang Ha

doi:10.1107/S1600536812013062

. 2012 Mar 31;68(Pt 4):m518. doi: 10.1107/S1600536812013062

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

Kwang Ha ^a,^*

PMCID: PMC3343900 PMID: 22589868

Abstract

The asymmetric unit of the title compound, [Pt(C₁₀H₉N₃)₂]Br₂·H₂O, contains two crystallographically independent half-molecules of the cationic Pt^II complex, two Br⁻ 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 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.

Related literature

For the crystal structures of the related Pd^II and Pt^II complexes, see: Živković et al. (2007 ▶); Antonioli et al. (2008 ▶); Guney et al. (2010 ▶).

Experimental

Crystal data

[Pt(C₁₀H₉N₃)₂]Br₂·H₂O
M _r = 715.33
Triclinic,
a = 9.7870 (9) Å
b = 11.059 (1) Å
c = 12.1151 (12) Å
α = 109.448 (2)°
β = 104.538 (2)°
γ = 107.980 (2)°
V = 1080.70 (18) Å³
Z = 2
Mo Kα radiation
μ = 10.21 mm⁻¹
T = 200 K
0.27 × 0.17 × 0.12 mm

Data collection

Bruker SMART 1000 CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2000 ▶) T _min = 0.745, T _max = 1.000
6721 measured reflections
4109 independent reflections
3411 reflections with I > 2σ(I)
R _int = 0.024

Refinement

R[F ² > 2σ(F ²)] = 0.029
wR(F ²) = 0.069
S = 1.05
4109 reflections
274 parameters
H-atom parameters constrained
Δρ_max = 1.43 e Å⁻³
Δρ_min = −1.21 e Å⁻³

Data collection: SMART (Bruker, 2000 ▶); cell refinement: SAINT (Bruker, 2000 ▶); data reduction: SAINT; 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.

Supplementary Material

Crystal structure: contains datablock(s) global. DOI: 10.1107/S1600536812013062/bq2347sup1.cif

e-68-0m518-sup1.cif^{(31.1KB, cif)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected geometric parameters (Å, °).

Pt1—N1	2.013 (5)
Pt1—N3	2.030 (5)
Pt2—N6	2.014 (4)
Pt2—N4	2.024 (4)

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N1—Pt1—N3	87.10 (19)
N6—Pt2—N4	86.65 (17)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1A⋯Br1ⁱ	0.84	2.58	3.399 (6)	166
O1—H1B⋯Br1ⁱⁱ	0.84	2.54	3.374 (5)	171
N2—H2N⋯Br1ⁱⁱⁱ	0.92	2.38	3.289 (4)	171
N5—H5N⋯Br2	0.92	2.35	3.267 (4)	174
C2—H2⋯O1^iv	0.95	2.58	3.302 (8)	133
C11—H11⋯Br2ⁱⁱ	0.95	2.87	3.635 (6)	138
C13—H13⋯Br2^v	0.95	2.76	3.712 (6)	177
C20—H20⋯O1^vi	0.95	2.56	3.464 (8)	160

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) ; (vi) .

Acknowledgments

This work was supported by the Priority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011–0030747).

supplementary crystallographic information

Comment

The title compound, [Pt(dpa)₂]Br₂.H₂O (dpa = di-2-pyridylamine), was unexpected obtained from the reaction of K₂PtBr₆ with dpa. It seems that the Pt^IV ion reduced to the Pt^II ion in the reaction. Crystal structures of the related cationic Pd^II and Pt^II complexes, such as [Pd(dpa)₂](X)₂ (X = Cl or PF₆) (Živković et al., 2007; Antonioli et al., 2008) and [M(dpa)₂](sac)₂ (M = Pd or Pt; sac = saccharinate) (Guney et al., 2010), have been investigated previously.

The asymmetric unit contains two crystallographically independent half-molecules of the cationic Pt^II complex, two Br^- anions 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 PtN₄ 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, Br^- anions 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 K₂PtBr₆ (0.1016 g, 0.135 mmol) in H₂O (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 H₂O 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.