PREPARATION AND CHARACTERIZATION OF DINUCLEAR COBALT(III) COMPLEXES CONTAINING 4 DIFFERENT KINDS OF LIGANDS - GLYCINATO, ETHYLENEDIAMINE, ETHYLENEDIAMINE-N,N'-DIACETATO, AND MU-HYDROXO

Four geometrical isomers of [Co(gly) (en)Co(edda) (mu-OH)2]+ were prepared by treating a solution containing [Co(edda)(OH2)2]+ and [Co(gly)(en)(OH2)2]2+ under basic condition and optically resolved by the chromatographic method. The geometrical structures and absolute configurations of the optically active isomers were assigned on the basis of the NMR, UV, and CD spectral data; the assignments were confirmed based on the spectral data of the mononuclear species which were obtained by the acid hydrolysis of each isomer. Two of the four geometrical isomers are constructed with the a-[Co(edda)(mu-OH)2] and mer(O)-[Co(gly)(en)(mu-OH)2] moieties, and the other two with the beta-[Co(edda)(mu-OH)2] and fac(O)-[Co(gly)(en)(mu-OH)2] moieties, the dinuclear structures being stabilized by the two N-H ... O hydrogen bonds between the amino H on one metal ion and the carboxyl O on the other metal ion in the dinuclear complex ion.