X-ray crystallographic and physical investigation of tricyanomethanide and dicyanamide complexes of cobalt(II) with imidazole and its methyl derivatives

Summary Reaction of Co^II with N(CN) _inf2 ^sup– or C(CN) _inf3 ^sup– in the presence of imidazole (iz) or its methyl derivatives (2-meiz and 4-meiz) gave eight compounds of Co^II: ligand stoichiometry 12, including two isomeric pairs ( and ) for the complexes Co{C(CN)₃}₂(2-meiz)₂] and Co{C(CN)₃}₂-(4-meiz)₂]. The complexes were studied by electronic and i.r. spectroscopies. For -Co{C(CN)₃}₂(2-meiz)₂] singlecrystal X-ray analysis was performed; its crystal structure consists of one-dimensional chains, formed by C(CN) _inf3 ^sup– anions bridging between the Co^II atoms. The Co^II atom is nearly octahedrally coordinated by two tertiary nitrogens of 2-meiz and four nitrogens of C(CN) _inf3 ^sup– . The spectra of these compounds and of the complexes with iz, as well as that of -Co{C(CN)₃}₂(4-meiz)₂], indicate all these compounds to have basically the same bridging polymeric octahedral structure. However, the spectra indicate distorted tetrahedral structures for the remaining compounds.