Crystal structure of di-aqua-bis-(2,6-di-methyl-pyrazine-κN)bis-(thio-cyanato-κN)cobalt(II) 2,5-di-methyl-pyrazine tris-olvate.

Abstract

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).