Synthesis and characterization of Δ-cis(N)-trans(O5)-RR sodium bis-((S)-α-alaninato-N-monopropionato)cobaltate(III) isomer

Abstract

Of the 12 possible diastereoisomers only Δ-cis(N)-trans(O5)-(RR)-Na[Co(alamp)2] isomer was isolated. Possible reasons explaining stereospecific coordination of ligand are discussed in terms of steric intra- and interligand interactions arising from the mutual position of -CH3 and N-CH2-CH2- groups. These exclude all isomers with SS or RS configuration of secondary nitrogen atoms. For the determination of the absolute configuration visible absorption, 1H, 13C NMR, circular dichroism and molecular models were employed.