Preparation and Stereochemistry of Cobalt(III) Complexes with Ethylenediamine-N-acetate and 3-Azapentane-1,5-diamine or 3-Methyl-3-azapentane-1,5-diamine

Abstract

Abstract Four geometrical isomers possible in each of [Co(edma)(dien)]2+ and [Co(edma)(mdien)]2+, where edma, dien, and mdien denote ethylenediamine-N-acetate, 3-azapentane-1,5-diamine, and 3-methyl-3-azapentane-1,5-diamine respectively, and facial isomer of [Co(edma)(NH3)3]2+ were prepared and resolved into optically active isomers by a column-chromatographic method. The structural assignments of these geometrical isomers were carried out on the basis of the absorption, 1H NMR, and 13C NMR spectral data. The absolute configurations of the optically active isomers containing facially coordinated edma were determined by 1H NMR measurements of the glycinate-ring methylene (–CHD–) of edma stereospecifically deuterated in a weak basic D2O. The relationship between the absolute configurations and the CD spectral behaviors of these isomers is also discussed.