M. Hvastijova et al., Cyanamidonitrate-nickel(II) and -cobalt(II) complexes of imidazole ligands: X-ray crystallography and spectroscopic investigation, POLYHEDRON, 19(8), 2000, pp. 1021-1027
New cyanamidonitrate complexes with imidazole (iz) and its methyl derivativ
es (meiz) of the type [M(NO2NCN)(2)L-4] (with M = Ni, L = iz, 1-, 2-, 4-mei
z; M = Co, L = iz, 1-, 4-meiz) and [CoL4] (NO2NCN)(2) (with L = iz, 2-meiz)
have been prepared and characterized by spectroscopic methods. The crystal
structures of [Ni(NO2NCN)(2)(1-meiz)(4)] and [Co(NO2NCN)(2)(iz)(4)] have b
een determined by X-ray crystallography. The metal(II) environment is pract
ically octahedral, composed of four tertiary nitrogens from imidazole ligan
ds and two nitrile nitrogens from cyanamidonitrate groups. According to the
spectral results, similar molecular structures can be assumed for all rema
ining [M(NO2NCN)(2)L-4] compounds. On the other hand, compounds [CoL4] (NO2
NCN)(2) consist of tetrahedral complex cations [CoL4](2+) which are electro
statically attracted with NO2NCN-. An isomeric pair, [Co(NO2NCN)(2)(iz)(4)]
and [Co(iz)(4)](NO2NCN)(2), of octahedral and tetrahedral structure, respe
ctively, were characterized. (C) 2000 Elsevier Science Ltd All rights reser
ved.