Synthesis, resolution and spectral properties of the cobalt(III) complex of the hexadentate ligand 2,2',2'-[(cyclohexane-1,3,5-triyl)trithio]tris(ethanamine)

The synthesis of a potentially hexadentate ligand 2,2',2''-[(cyclohexane-l,3,5-triyl)trithio]tris(ethanamine) (atch) is described. The ligand forms a hexadentate cobalt(III) complex which has been resolved into its catoptric forms. The (+)520-[Co(atch)]3+ complex displays a strikingly large dichroism in the region of the first ligand field transition in the circular dichroism spectrum with Δε480+ 11.9 mol-1 1. cm-1 and has been assigned the Λ absolute configuration by comparisons of the circular dichroism with those of similar complexes of known absolute configuration. Attempts to cap the complex by using nitromethane and formaldehyde under basic conditions are described.