Crystal structure of diaquabis(2,6-dimethylpyrazine-kappa N)bis(thiocyanato-kappa N)-cobalt(II) 2,5-dimethylpyrazine trisolvate

In the crystal structure of the title compound, [Co(NCS)(2)(C6H8N2)(2)(H2O)(2)]center dot 3C(6)H(8)N(2), the Co-II cation is coordinated by two terminally N -bound thiocyanate anions, two water molecules and two 2,6-dimethylpyrazine ligands, forming a discrete complex with a slightly distorted octahedral N4O2 coordination environment. The asymmetric unit contains one Co-II cation and three halves of 2,5-dimethylpyrazine solvate molecules, all entities being completed by inversion symmetry, as well as one thiocyanate anion, an aqua ligand and a 2,6-dimethylpyrazine ligand, all in general positions. In the crystal, discrete complexes are arranged in a way that cavities are formed where the noncoordinating 2,5dimethylpyrazine molecules are located. The coordination of the latter to the metal is prevented due to the bulky methyl groups in vicinal positions to the N atoms, leading to a preferential coordination through the 2,6-dimethylpyrazine ligands. The complex molecules are linked by O-H center dot center dot center dot N hydrogen bonds between the water H atoms and the N atoms of 2,5-dimethylpyrazine solvent molecules, leading to a layered structure extending parallel to (100).