Bis(O-ethyl dithiocarbonato-κ2 S,S′)bis(pyridine-3-carbonitrile-κN 1)nickel(II)

The Ni2+ ion in the title complex, [Ni(C3H5OS2)2(C6H4N2)2], is in a strongly distorted octahedral coordination environment formed by an N2S4 donor set, with the Ni2+ ion located on a centre of inversion. In the crystal, weak C—H⋯S and C—H⋯N interactions are observed.

The Ni 2+ ion in the title complex, [Ni(C 3 H 5 OS 2 ) 2 (C 6 H 4 N 2 ) 2 ], is in a strongly distorted octahedral coordination environment formed by an N 2 S 4 donor set, with the Ni 2+ ion located on a centre of inversion. In the crystal, weak C-HÁ Á ÁS and C-HÁ Á ÁN interactions are observed.
Data collection: CrysAlis PRO (Oxford Diffraction, 2007); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: PLATON (Spek, 2009) and PARST (Nardelli, 1995 Xanthates (O-alkyl/aryl dithiocarbonates) have been known for a long time and many adducts of metal xanthates with different ligands have been prepared and studied in the last several decades. Adducts of transition metal xanthates with N-donor ligands are well represented in the literature, the most extensively studied being those of nickel(II). Nitrogen containing adducts of nickel(II) xanthates are known to adopt a variety of supramolecular assemblies (Tiekink & Haiduc, 2005). The Ni atom in (I) is located on a center of inversion and exists within a trans-N2S4 donor set that defines an approximately octahedral coordination geometry. The chelating xanthate ligand forms essentially equivalent Ni-S bond distances; this equivalence is reflected in the parameters defining the xanthate ligand. The bond angles around the Ni atom are in the range of 73.83 (2) to 180.00 (3)°. The Ni-S bond lengths, Ni1-S1 = 2.4335 (5); Ni1-S2 = 2.4450 (6) Å, are in good agreement with those reported for other Ni-dithiocarbonato complexes (Tiekink & Haiduc, 2005;Dakternieks et al., 2006;Hill & Tiekink, 2007;Hogarth et al., 2009). Molecules in the unit cell are packed together to form well defined layers. While no classical hydrogen bonds are present, the C-H···S and C-H···N hydrogen bonds (Table 1) play important role in stabilizing the crystal structure.

Experimental
The title complex was prepared by stirring the parent nickel(II) ethylxanthate (0.781g,0.0026 mol.) with 3cyanopyridine(0.541g, 0.0052 mol.) in acetone(60 ml) for one hour. Green crystals of (I) were isolated by the slow evaporation of the resulting solution of the complex.

Refinement
All H atoms were positioned geometrically and were treated as riding on their parent C atoms, with C-H distances of 0.93-0.97 Å and with U iso (H) = 1.2Ueq(C) or 1.5Ueq(methylC). Fig. 1. ORTEP view of the molecule with displacement ellipsoids drawn at the 30% probability level. Unlabeled atoms are generated by the symmetry operation -x, 1-y, 1-z.

Figures
supplementary materials sup-2  as those based on F, and R-factors based on ALL data will be even larger.