Complexation of amino sugars with cobalt(III)bis(phenanthroline)

Complexes of Co(III)bis(phenanthroline) with beta-D-mannosamine and alpha-D -galactosamine can be isolated as the triiodide salts. The complex with D-m annosamine has the Delta-configuration at Co(III). Complexation with D-gala ctoamine gives the Delta- in excess over the Lambda- complex, and the Delta -complex can be isolated chromatographically. Complexation involves cis-l-O H and 2-NH2 groups, eq, ax respectively with beta-mannosamine and ax, eq re spectively, with alpha-galactosamine, as with alpha-glucosamine, based on H -1 NMR spectra. Galactosamine complexes in aqueous solution decompose to th e free sugar, but the mannosamine complex is much more stable. (C) 1998 Els evier Science Ltd. All rights reserved.