Synthesis and crystal structure of -poly[cobalt(II)-di-μ-chlorido-μ-pyridazine-κ:].

The reaction of cobalt dichloride hexa-hydrate with pyridazine leads to the formation of crystals of the title compound, [CoCl(CHN)]. This compound is isotypic to a number of compounds with other divalent metal ions. Its asymmetric unit consists of a Co atom (site symmetry 2/), a chloride ion (site symmetry ) and a pyridazine mol-ecule (all atoms with site symmetry ). The Co cations are coordinated by four chloride anions and two pyridazine ligands, generating -CoNCl octa-hedra, and are linked into [010] chains by pairs of μ-1,1-bridging chloride anions and bridging pyridazine ligands. In the crystal structure, the pyridazine ligands of neighboring chains are stacked onto each other, indicating π-π inter-actions. Powder X-ray diffraction proves that a pure crystalline phase was obtained. Differential thermonalysis coupled to thermogravimetry (DTA-TG) reveal that decomposition is observed at about 710 K. Magnetic measurements indicate low-temperature metamagnetic behavior as already observed in a related compound.