Study of the reactions of hexanitrocobaltates(III) with amino acids. VII. Geometrical isomerism and absolute configuration of dinitrobis(aminoacidato)cobaltate(III) ions

Dinitrobis(aminoacidato)cobaltate(III) salts with L-α-aminobutyric acid, aminoisobutyric acid, L-valine, L-norvaline, L-leucine, L-norleucine, and L-isoleucine were prepared and resolved into optical isomers. We report their electronic absorption, circular dichroism and infra-red spectra, and some PMR spectra. The date confirm our earlier assumption of the geometrical isomerism and absolute configuration of analogous ions with glycine, alanine, and β-alanine. The only geometrical isomer found in our preparations is the cis dinitro complex with amino groups trans. The (+)589-optical isomers are assigned the P(C2) absolute configuration