The synthesis of three
potentially sexadentate optically active sulphur-containing amino acids, 2,9-
diamino-4,7-dithiadecanedioic acid [(R,R)-ebc], 2,ll-diamino-5,8-dithiadodecanedioic
acid [(S,S)- ebhc] and 2,7-di(3'-thiabuty1)-3,6-diazaoctanedioic acid [(S,S)-ebm]
are described. Some metal complexes of the acids with cobalt, nickel and copper
are characterized by spectroscopic measurements. The complex�� (-)589[Co{(S,S)-ebm}] ClO4
is formed stereospecifically and an X-ray structural analysis shows it to have
the Δ-trans(O) configuration.
The c.d. spectrum shows the presence of three bands due to the splitting of the
T1g energy level by the effective C2 symmetry of the
ligand field. Some polymeric cobalt(11) and nickel(11) complexes are also
described. Spectral measurements indicate an octahedral coordination of the
ligands involved. Several copper(11) complexes are also described.
Preparation and Spectroscopic Studies of Cobalt(III) Complexes Containing Optically Active Seven-membered Chelate Ligands