OPTICALLY ACTIVE BIS(BIQUANIDE)COBALT(III) COMPLEXES CONTAINING AMINO ACIDS

Abstract

Biguanide-amino acid complexes of the type Co(am)(Hbg)³⁺ ₂, where am is the anion of glycine, sarcosine, L-alanine, L-valine, L-isoleucine, or L-proline, have been prepared and resolved. The absorption, circular dichroism (CD) and proton magnetic resonance spectra (for the alanine and valine complexes) are reported. For some salts of some of the complexes of optically active amino acids, one pure optical isomer could be obtained by slow crystallization from from the reaction solution. One optical isomer of the complexes containing optically active amino acids is present in the reaction mixture to a slightly greater extent than the other. The effects of hydroxide ion and heating on equilibration was studied. Assignments of absolute configurations were made from the CD spectra.