Dibromido(2,3-di-2-pyridyl­pyrazine-κ2 N 1,N 2)platinum(II)

Kwang Ha

doi:10.1107/S1600536811031643

. 2011 Aug 11;67(Pt 9):m1230. doi: 10.1107/S1600536811031643

Dibromido(2,3-di-2-pyridylpyrazine-κ² N ¹,N ²)platinum(II)

Kwang Ha ^a,^*

PMCID: PMC3200673 PMID: 22058856

Abstract

The Pt^II ion in the title complex, [PtBr₂(C₁₄H₁₀N₄)], is four-coordinated in a distorted square-planar environment by two N atoms of a chelating 2,3-di-2-pyridylpyrazine ligand and two bromide anions. In the crystal, the pyridyl ring coordinated to the Pt atom is inclined slightly to its carrier pyrazine ring [dihedral angle = 14.7 (2)°], whereas the uncoordinated pyridyl ring is inclined considerably to the pyrazine ring [dihedral angle = 51.9 (3)°]. The dihedral angle between the two pyridyl rings is 57.7 (3)°. Two complex molecules are assembled through intermolecular C—H⋯N hydrogen bonds, forming a dimer-type species. Intramolecular C—H⋯Br and C—H⋯N hydrogen bonds are also present.

Related literature

For the crystal structure of [PtCl₄(dpp)] (dpp is 2,3-di-2-pyridylpyrazine), see: Delir Kheirollahi Nezhad et al. (2008 ▶).

Experimental

Crystal data

[PtBr₂(C₁₄H₁₀N₄)]
M _r = 589.14
Monoclinic,
a = 8.9084 (11) Å
b = 9.9817 (12) Å
c = 16.727 (2) Å
β = 94.104 (3)°
V = 1483.6 (3) Å³
Z = 4
Mo Kα radiation
μ = 14.84 mm⁻¹
T = 200 K
0.17 × 0.10 × 0.04 mm

Data collection

Bruker SMART 1000 CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T _min = 0.590, T _max = 1.000
10590 measured reflections
3642 independent reflections
2415 reflections with I > 2σ(I)
R _int = 0.060

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.099
S = 1.01
3642 reflections
190 parameters
H-atom parameters constrained
Δρ_max = 3.12 e Å⁻³
Δρ_min = −1.54 e Å⁻³

Data collection: SMART (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); 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, I. DOI: 10.1107/S1600536811031643/hy2455sup1.cif

e-67-m1230-sup1.cif^{(16.6KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811031643/hy2455Isup2.hkl

e-67-m1230-Isup2.hkl^{(178.6KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Pt1—N1	2.020 (6)
Pt1—N3	2.033 (8)
Pt1—Br1	2.4116 (11)
Pt1—Br2	2.4142 (10)

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯N2ⁱ	0.95	2.55	3.396 (11)	148
C4—H4⋯Br1	0.95	2.66	3.289 (9)	124
C6—H6⋯N4	0.95	2.59	3.051 (11)	110
C9—H9⋯Br2	0.95	2.71	3.340 (10)	124

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Symmetry code: (i) Inline graphic .

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 (2010–0029626).

supplementary crystallographic information

Comment

In the title complex, [PtBr₂(dpp)] (dpp is 2,3-di-2-pyridylpyrazine, C₁₄H₁₀N₄), the Pt^II ion is four-coordinated in a distorted square-planar environment by two N atoms from the pyrazine ring and one pyridyl ring of the chelating dpp ligand and two bromide anions (Fig. 1). The coordination mode of the dpp ligand is similar to that of a mononuclear Pt(IV) complex [PtCl₄(dpp)] (Delir Kheirollahi Nezhad et al., 2008).

The main contribution to the distortion of the square-plane is the tight N1—Pt1—N3 chelate angle of 80.4 (3)°, which results in slightly bent trans axes [Br1—Pt1—N3 = 175.09 (18) and Br2—Pt1—N1 = 176.6 (2)°]. The Pt—N and Pt—Br bond lengths are nearly equivalent, respectively (Table 1). In the crystal, the pyridyl ring coordinated to the Pt atom is located slightly inclined to its carrier pyrazine ring, making a dihedral angle of 14.7 (2)°. On the contrary, the uncoordinated pyridyl ring is considerably inclined to the pyrazine ring with a dihedral angle of 51.9 (3)°. The dihedral angle between the two pyridyl rings is 57.7 (3)°. Two complex molecules are assembled through intermolecular C—H···N hydrogen bonds, forming a dimer-type species (Fig. 2 and Table 2). There are also intramolecular C—H···N and C—H···Br hydrogen bonds (Table 2). The complexes stack in columns along the c axis.

Experimental

To a solution of K₂PtBr₄ (0.297 g, 0.500 mmol) in H₂O (20 ml) was added 2,3-di-2-pyridylpyrazine (0.117 g, 0.501 mmol) and stirred for 3 h at room temperature. The formed precipitate was separated by filtration, washed with H₂O and acetone and dried at 50 °C, to give a redbrown powder (0.133 g). Crystals suitable for X-ray analysis were obtained by slow evaporation from an acetone solution.