Synthesis, crystal structure and thermal properties of bis­(aceto­nitrile-κN)bis­(3-bromo­pyridine-κN)bis­(thio­cyanato-κN)cobalt(II)

Single crystals of the title compound, [Co(NCS)(2)(C(5)H(4)BrN)(2)(C(2)H(3)N)(2)], were obtained by the reaction of Co(NCS)(2) with 3-bromo­pyridine in aceto­nitrile. The Co(II) cations lie on crystallographic inversion centers and are coordinated by two N-bonded thio­cyanate anions, two 3-bromo­pyridine and two aceto­nitrile ligands thereby forming slightly distorted CoN(6) octa­hedra. In the crystal, these complexes are linked by C—H⋯S and C—H⋯N hydrogen bonds into a three-dimensional network. In the direction of the crystallographic b-axis, the complexes are arranged into columns with neighboring 3-bromo­pyridine ligands stacked onto each other, indicating π–π inter­actions. The CN stretching vibration of the thio­cyanate anions is observed at 2066 cm(−1), in agreement with the presence of only N-bonded anionic ligands. TG-DTA measurements reveal that in the first mass loss the aceto­nitrile ligands are removed and that in the second step, half of a 3-bromo­pyridine ligand is lost, leading to the formation of a polymeric compound with the composition [(Co(NCS)(2))(2)(C(5)H(4)BrN)(3)]( n ) already reported in the literature.