MONO-AND DINUCLEAR COBALT(III) COMPLEXES WITH S-TYROSINE

Abstract

In a direct synthesis, by oxidation of cobalt(II) to cobalt(III) by oxygen in the presence of the lithium salt of S-tyrosine, the following isomers of the tris(S-tyrosinato)cobalt(III) complex were obtained: Δ-(−)₅₈₉-facial, Λ-(+)₅₈₉- and Δ-(-)₅₈₉-meridional, and (⁻)₅₈₉-anti(N)-Δ-cis(N), cis(O)-Δ-cis(N), cis(O)-di-μ-hydroxo-terakis(S-tyrosinato)dico-balt(III). Their composition was established by microanalysis, and their structure by electronic absorption, CD and ¹³C NMR spectra. Finally, it was found that Δ-mer-tris(S-tyrosinato)cobalt(III) described earlier is a mixture of Δ and Δ diastereomers of the complex.

Key Words:

• S-tyrosine
• cobalt(III)
• synthesis
• configuration
• CD spectra
• ¹³C NMR spectra