SYNTHESIS AND X-RAY CRYSTAL-STRUCTURE OF THE COBALT(III) COMPLEX OF YL-6-(4-AMINO-2-AZABUTYL)-1-THIA-4-AZACYCLOHEPTANE (ATAC), CIS-[CO(ATAC)CL2]CLO4-1 2H2O/

The crystal structure of cis-[Co(atac)Cl2]ClO4.1./2H2O [atac = l-6-(4- amino-2-azabutyl)-1-thia-4-azacycloheptane] has been determined by X-r ay diffraction methods. The tetradentate ligand atac contains the N3S donor set and is coordinated to cobalt(III) through a secondary amine and a thioether in the cycloheptane ring, and through a pendant primar y amine. The chloro ligands coordinated in a cis arrangement make up t he octahedral environment of the metal ion.