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

In the crystal structure of the title compound, [Co(NCS)2(C6H8N2)2(H2O)2]·3C6H8N2, the CoII 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 CoII 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 2,5-dimethylpyrazine 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...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).