Synthesis, crystal structure and properties of bis(isoselenocyanato-κN)tetrakis(4-methoxypyridine-κN)cobalt(II)

Abstract

Reaction of CoCl2·6H2O with KNCSe and 4-methoxypyridine in water led to the formation of the title compound, [Co(NCSe)2(C6H7NO)4] or Co(NCSe)2(4-methoxypyridine)2, which was characterized by single-crystal X-ray diffraction. Its asymmetric unit consists of one crystallographically independent Co cation, two selenocyanate anions and four 4-methoxypyridine coligands in general positions. In the crystal structure, the cobalt cations are sixfold coordinated by two terminal N-bonded selenocyanate anions and four 4-methoxypyridine coligands within a slightly distorted octahedral coordination. Between the complexes, weak C—H...Se interactions are found. IR spectroscopic investigations revealed that the CN stretching vibration of the anionic ligands is observed at 2068 cm−1, which is in agreement with the presence of only terminally coordinated selenocyanate anions. PXRD measurements prove that a pure compound was obtained. Differential thermoanalysis coupled to thermogravimetry (DTA-TG) at different heating rates shows that the TG curves are poorly resolved. PXRD measurements of the residue obtained by a TG measurement prove that an amorphous compound was obtained.