Crystal structure of di-aqua-bis-(2,6-di-methyl-pyrazine-κN (4))bis-(thio-cyanato-κN)cobalt(II) 2,5-di-methyl-pyrazine monosolvate.

Abstract

In the crystal structure of the title compound, [Co(NCS)2(C6H8N2)2(H2O)2]·C6H8N2, the CoII cation is coordinated by the N atoms of two terminal thio­cyanate anions, the O atoms of two water mol­ecules and two N atoms of two 2,6-di­methyl­pyrazine ligands. The coordination sphere of the resulting discrete complex is that of a slightly distorted octa­hedron. The asymmetric unit comprises a CoII cation and half of a 2,5-di­methyl­pyrazine ligand, both of which are located on centres of inversion, and a water ligand, a 2,6-di­­methyl­pyrazine ligand and one thio­cyanate anion in general positions. In the crystal, the discrete complexes are arranged in such a way that cavities are formed in which the 2,5-di­methyl­pyrazine solvent mol­ecules are located. The coordination of the 2,5-di­methyl­pyrazine mol­ecules to the metal is apparently hindered due to the bulky methyl groups in vicinal positions to the N atoms, leading to a preferential coordination of the 2,6-di­methyl­pyrazine ligands. The discrete complexes are linked by O—H⋯N hydrogen bonds between one water H atom and the non-coordinating N atom of the 2,6-di­methyl­pyrazine ligands. The remaining water H atom is hydrogen bonded to one N atom of the 2,5-di­methyl­pyrazine solvent mol­ecule. This arrangement leads to the formation of a two-dimensional network extending parallel to (010).