Dibromido(di-2-pyridyl sulfide-κ2 N,N′)zinc(II)

The molecule of the title compound, [ZnBr2(C10H8N2S)], contains a six-membered chelate ring in a boat conformation in which the Zn atom is coordinated by two Br atoms and by the two pyridyl N atoms of a single di-2-pyridyl sulfide (dps) ligand within a slightly distorted tetrahedron. The dihedral angle between the pyridine rings is 52.7 (1)°. As is usual for this type of complex, the sulfide group does not participate in the zinc coordination.

The molecule of the title compound, [ZnBr 2 (C 10 H 8 N 2 S)], contains a six-membered chelate ring in a boat conformation in which the Zn atom is coordinated by two Br atoms and by the two pyridyl N atoms of a single di-2-pyridyl sulfide (dps) ligand within a slightly distorted tetrahedron. The dihedral angle between the pyridine rings is 52.7 (1) . As is usual for this type of complex, the sulfide group does not participate in the zinc coordination.
In general, dps is a versatile ambidentate ligand that, due to its conformational flexibility, can act in N,N'-bidentate (Tresoldi et al., 1992;Kondo et al., 1995 andNicolò et al., 1996) or bridging (Tresoldi et al., 1991 andTeles et al., 1999) coordination modes toward many metals, resulting in complexes with different stereochemistry. When dps is connected to a metal atom as a chelate ligand, a six-membered ring in boat conformation is formed, differently from its rigid analogues 2,2'-bipyridine that generates a pentacyclic chelate in a planar arragement. In addition, in some cases dps can act as tridentate ligand in a N,N,S-coordination mode involving metal-sulfur interactions (Anderson & Steel, 1998).
In the molecular structure the coordination geometry about the Zn atom is almost tetrahedral with bonds being formed to two Br atoms and the two pyridyl N atoms of a single dps ligand (Fig. 1). These interactions result in the formation of a six-membered chelate ring in a boat conformation. The X-Zn-X angles (X = Br, N) range from 94.7 (1) to 118.38 (2)°, the largest being Br-Zn-Br. The Zn-Br and Zn-N distances are in the range of 2.3504 (6)-2.3527 (5) and 2.055 (3)-2.058 (3) Å. The structural parameters in the bps molecule are quite regular. In particular the C-S bonds of 1.776 (4) Å (S1-C1) and 1.778 (4) Å (S1-C11) are in good agreement with those expected for C(sp 2 )-S bonds (1.77 Å, Tresoldi et al. 1992).

Experimental
ZnBr 2 and 2,2'-bipyridyldisulfide was obtained from Alfa Aesar, methanol was obtained from Fluka. 0.125 mmol (28.1 mg) zinc(II) bromide, 0.0312 mmol (6.87 mg) 2,2'-bipyridyldisulfide and 3 ml of methanol were transfered into a test-tube, which was closed and heated to 110 °C for three days. On cooling colourless block-shaped single crystals of the title compound were obtained.

Refinement
All H atoms were located from the difference Fourier map but were positioned with idealized geometry and were refined isotropically with U eq (H) = 1.2 U eq (C) of the parent atom using a riding model with C-H = 0.97 Å. Geometric parameters (Å, °)