Preparation and Characterization of uns-cis-Trimethylenediamine-N,N′-diacetato Cobalt(III) Complexes with Several l -Amino Acids

Five uns-cis-mer and two uns-cis-fac complexes of (trimethylenediamine-N,N′-diacetato)(l-amino carboxylato)cobalt(III) were prepared, where l-amino carboxylate denotes l-alaninate, l-valinate, l-prolinate, l-hydrogen aspartate, or l-hydrogen glutamate ion. The complexes were separated into the fourteen isomers, Δ-, Λ-uns-cis-mer for the l-alaninato, l-valinato, and textscl-prolinato complexes, and Δ-, Λ-uns-cis-mer and Δ-, Λ-uns-cis-fac for the l-hydrogen aspartato and l-hydrogen glutamato complexes. They were characterized by their proton magnetic resonance, absorption and circular dichroism spectra. Each of the uns-cis-mer and uns-cis-fac isomers showed the characteristic CD behavior in the second absorption band region. The Λ-uns-cis-mer and Δ-uns-cis-fac isomers of the l-aspartato and l-glutamato complexes were stereoselectively formed, the formation ratios of the isomers being estimated spectrophotometrically.