Mixed cobalt(III) complexes with aromatic amino acids and diamines. III. Absolute structure of Lambda-trans(O)-(1,2-diaminoethane-kappa(2)N,N)bis(S-tyrosinato)cobalt(III) chloride tetrahydrate.

The title compound, [Co(C(9)H(10)NO(3))(2)(C(2)H(8)N(2))]Cl.4H(2)O, is one of six possible diastereomers of the (1,2-diaminoethane)bis(S-tyrosinato)cobalt(III) complex. The cobalt(III) ion has an octahedral coordination, with three five-membered chelate rings which have deformed coordination angles and coordinated O atoms in trans positions. In comparison with the previously reported crystal structure of the Delta-C(1)-cis(O) diastereomer [Miodragović et al. (2001). Enantiomer, 6, 299-308], the compound presented in this paper has more planar five-membered aminocarboxylate rings. Complex cations, chloride anions and water molecules of crystallization are linked together by a network of hydrogen bonds. The chloride anions lie approximately between two Co atoms and form hydrogen bonds with all coordinated NH(2) groups. In the crystal structure, there is a weak intermolecular pi...pi interaction between the phenyl rings.