Cobalt(III) complexes with a tetraaza macrocyclic ligand and some heterocyclic dithiocarbamates

Four new cobalt(III) complexes of the general formula [Co(Rdtc)cyclam](ClO4)(2), where cyclam and Rdtc(-) refer to 1,4,8,11-tetraazacyclotetradecane and 2-, 3-, 4-methylpiperidine (2-, 3-, 4-wMeepipdtc(-)) or 4-thiomorpholine (Timdtc(-)) dithiocarbamates, respectively, have been prepared. Elemental and thermal analyses, VIS, IR and H-1 and C-13 NMR spectroscopy have been used to characterized them. In the complexes, cobalt is hexa-coordinated in an octahedral geometry of a folded macrocyclic ligand and dithiocarbamates are bound as bidentates. As regards to the influence of the position of the methyl group on the piperidine ring, the nu(C - N) and nu(C - S) values increase in the order 2-Mepipdtc(-) < 3-Mepipdtc(-) < 4-Mepipdtc(-). Furthermore, the position of the methyl substituent also influences the thermal stability of the complexes and the order of stability decreases in the opposite order.